Rewinding a DC motor for different voltages

I modified small DC motors, like used in toys and such but now I have one that requires to do it properly.Motor in question runs on 24V and uses about 3.5A under full load.Drives a high pressure water pump on either side of the shaft.The rotor is basically empty with just a few turns of wire and lots of empty space.I assume the same model is used for multiple power configurations by the manufacturer.For the toys my basic approach was to just calculated the number of turns or to count them when removing.From there I get the voltage per turn and can rewind accordingly.So in theory and by blissfully ignoring all higher things involved I could do this motor the same way.Right now I see 10 windings per coil, so with thicker wire I would use 5 to run it on 12V at roughly the same speed.Only problem is that thing then would use around 7.5 to 8A when running under full load and get quite hot.I need the speed to keep the flowrate at the same 7.5L per minute but I also need the power to be able to still get the 120PSI from just 12V.Isn't there any winding trickery that would allow me to reduce the required current a bit without sacrificing on speed or torque?

Topic by Downunder35m   |  last reply


how to design a wind powered water lifting system?

I need to lift water from the higher tank to the lower tank ( against gravity)...i difference between tank a and tank b is 20 cm only

Question by lulu114   |  last reply


4 wheeled Quad-Cycle!

Has anybody made or thought about making an Instructable to make a 4 wheeled bike-like a car? I've seen them on the Internet for $3-4000. Thought it would be interesting because of higher gas prices.

Topic by potofgold   |  last reply


Spain Turning Into Desert as Water Wars Begin

Parts of Spain are feeling the pinch of too many people going after too little water. Some of the land is drying out after water-thirsty resorts and corn farms in the arid land guzzle it all up and leave nothing behind. About the only thriving part is the black market which is charging ever higher prices.Where I live in Oakland we're getting phone calls from the water utility to cut back on water use and are facing higher prices ourselves. People could even face penalties for excessive watering of gardens. Makes me feel OK for letting most of our plants shrivel up and die after all. Water Shortage in Spain

Topic by fungus amungus   |  last reply


custom cellphone battery charger drains out the cellphone battery..why?? Answered

I made a cellphone battery charger from 3 AA batteries.The combination of 3 AA batteries was at a higher potential than the cellphone battery, but when i connected both of them for charging, the potential of 3 AA batteries remained same but the cellphone battery was completely drained.why??If someone could explain maybe??

Question by chatsbk007   |  last reply


[ask] Blinking led advantage

Hi all, i want to ask in order to use less power (voltage, current or watt, i'm confuse about that) to light led. If i power up 100 leds blinking in parallel, blinking one by one, 50 hertz or higher, Am i get kWh (kilo watt hour) lower value instead powering 100 led without blinking...? Thx

Topic by shinjiyuubix   |  last reply


Is it safe to melt polycarbonate? Answered

I'm interested in trying to do something with the dozens of old CD's and DVD's.  I was thinking of trying to melt the polycarbonate and shape it while it's  Pliable. I understand polycarbonate melts at around 150 degrees C, so it's possible to melt in an oven, but is it safe?  Will it release any toxic fumes, or does it only vent at higher temps? Also, will it deform\shrink as it cools, or will it hold it's shape? Thanks!!!

Question by Morgantao   |  last reply


can i use 500 watt juicer and mixer motor for electric bicycle?

On motor specification it is written 500 watt , 50 hz ac motor , but when i plug it in 12 volt dc battery it runs slowly it can stop it with hand but i hope in higher dc volt it will run enough to use in my electric bicyle. it is philips juicer and mixer and grinder purchased from india

Question by Suraj Basnet   |  last reply


AC Pump Motor Not Working? Answered

I have just come across a free pool pump and hope I will be able to get it up and running.  So far I have had absolutely no luck with it.  The run switch seems to work and so I don't think it is the culprit.  I have even tried two newish capacitors which I know work.  When I plug it in it just hums.  It doesn't throw the breaker so I don't think a short is the problem and it isn't bound up as I can turn it easily by hand.  There is also no sign of twitching as the motor attempts to start.  The overpower protection switch seems to be good and shows continuity across all polls.  The motor itself has continuity where I believe it is necessary so I am at a loss for what could be wrong.  The motor says it is good for 115 volts as well as higher but I would prefer not to shove higher voltages through it if not necessary.  Do any of you have ideas on how I could get this up and running as the pump is in excellent condition and will be useful as a runoff booster pump.

Question by jj.inc   |  last reply


Nano-buble_ #tech_#eng_#design_@thermodinamics

Hi, I'm looking for some help to develop a nano-buble bubeling device.(thermodynamics, control logic, sensing, material technology - I touch all this subjects but in content) It will be for a good cause, like humanity, affordability, clean water at affordable costs. Also, electolisys has a higher efficiency in generation if H2o. It might not be the solution but it's still on the books/on the table. Get in touch @: remembereco@gmail.com or post comments on this platform. A great idea! Best wishes, ip

Topic by JagodaN   |  last reply


Wind Powered Quad-Cart

I haven't seen anything this on here so I thought I'd step up. Engineers (or anyone who fancies themselves A DIYer) I found a few days back I little some very interesting Wind Powered Rides...six-or-seven-ways-wind-powers-vehicles OK so we know it CAN be done, but can it be done by a DIYer? OK here's my concept, Design and shape are optional but basic components are such: Take a pair of multi-speed Bicycles, their gearing will be the basic propulsion for this vehicle. Take one of the "bikes" and hook up a prop where the pedals "where" and set the wheel output to be higher then the prop speed, this should take care of the foreward movement once going. Now for the initial starting power (Bike 2), this can either be by petal, or by electric (solar/battery- up to you) But the basis for this whole thing is simple energy transfer, if the moving air over the prop causes the drive wheels to go, and by having them geared higher, the vehicle SHOULD move faster the faster you go ..Right? Can I get some math to back this up? it sounds like it would work.

Topic by Green_Primus   |  last reply


My halfstack squeals. Help pleasee?

So. I have a halfstack. I dont know too much about it but here's what i know: It has a Crate Amp head and a Peavy Cabinet.  when i turn the volume on the front higher that about 2, the amp audibly hums, loud enough that it would make this a poor idea to use on stage. any ideas on why this is happening or how much it'll take to fix it?

Question by PyroMaster007   |  last reply


Solar panel: Shattered glass - epoxy or replace the glass? Answered

Hello, I see many projects/videos about making solar panels or repairing shattered glass on solar panel with things like epoxy. But I have found nothing about chaging the glass of the solar panel. The cost of epoxy  for a repair seems quite high (30$+?) and maybe not always suited long term. Assuming the cost of the glass wasnt much higher, is there something practical stoping a repair by chaging the glass rather than using epoxy? Thank you!

Question by RincewindT   |  last reply


what should I do with 20 1-inch diameter steel balls? Answered

My brother recently gave me 20 1 inch diameter steel balls that he was trying to use to cool down coffee without watering it down (in hindsight, aluminum has a much higher heat density, but that's beside the point). I've had them laying around for a while now, and apart from a big newton's cradle or maybe a huge marble machine, I can't think of anything to do with them. ideas?

Question by codongolev   |  last reply


Cheap Auto Range Multimeter? Answered

As the question states. Anyone know of a good, cheap, auto range DMM? The more features and higher ranges the better. I don't need true RMS, would like capacitance checking ability as I reuse a lot of used electronic components from stuff people throw away, and I always saw auto range as more of a convenience, not a necessity. I would like to spend as little as possible, as I'm sure I'll eventually burn it out on one of those used components, like I did the $20 harbor freight clamp meter I had.

Question by Dochide   |  last reply


How to choose wire gauge for Brushless DC motor?

I'm planning to build a Brushless DC motor, with inrunner perm mag rotor and stator on the outside. How can i determine the proper copper wire gauge for the stator windings? How much current will the motor pull? At first i thought it was just "Power = Voltage * current", so knowing the power and the voltage i should be able to figure the current. However, when the motor is spinning it generates back EMF, which counters the applied voltage and diminishes the current. At no load, the motor should draw no current for an ideal motor, and only a small current in real life to overcome friction and losses. In any case it would be much lower than the nominal current. So, for instance, a 1000w motor at 50v should draw 20A nominal, but in most situations it would be less than that? How much is the starting current, when you have to overcome inertia/tire friction? I know the motor can take higher currents for small amounts of time, before it gets too hot,but how can i determine what will be the "average" current. Is there a rule of thumb that motor designers use?  Also, the amp rating for each AWG seems to vary a lot. Some places list a conservative rating that is used for home wiring. But other places list much higher currents. If the stator is on the outer side and exposed to air, how much current can the copper handle for each AWG? Any insight will be appreciated, thanks.

Question by SlickT   |  last reply


Confused Crocodile

I'm a confused crocodile...I wanted to compete in the 3d money clip challenge and will still design something for it :) . After numerous times of trying to make the software work it just didn't so I'm going to try to use some other CADs that I have. With that being said here lies my confusion about this contest.The prize(s) for the 3d money clip contest is a $100.00 credit for five winners. I went to the website and there's a membership fee and if you aren't a member then the cost of services is higher. Plus, there's an hourly charge for the services and I'm basically confused as to the benefit of a $100.00 voucher/credit. Would that be enough to make a 3d print of the 3d model for the winners of the contest?

Topic by N1K1_1NC.   |  last reply


What's the cheapest way to run all these F15T8 fluorescent tubes?

I have a bunch of F15T8 fluorescent tubes, and I want to make my own light fixture with something like 4-8 of them running at the same time. Doing some research has shown me that I need a ballast. Nearly all of the ballasts I found online for f15t8 were only for 1 or 2 lamps, and I don't really want to buy more than one. Is there any way I can use a ballast rated for a higher watt bulb or something? What happens if you put a F15T8 in a F32T8 ballast? 

Question by conrad141 


New inventor seeks industrial designers......

Hello, I am inventing a new golfing product.  I have a working prototype and I'm filing my patent now.  But I needs some help with improving the design.  I'm not a professional designer but I have some mockups in Sketchup.  I am looking for someone with experience designing commercial products in solid works.   The product is going to be made out of plastic and it's has a few moving parts.  For the most part it is very simple but I want to make it into a higher quality product.  If your are interested in working for me as a consultant, let me know and I will send you an NDA to sign. Thanks, Joe

Topic by dznodes   |  last reply


Can a charger made for 1600mah batteries safely and effectively charge 2500mah batteries? Answered

I have several dead battery packs for my 18v power tools.  Planning to rebuild them and figuring I might as well upgrade their run time while I'm at it.  The original battery packs are 1600mah but I can get 2500mah battery cells that are the same size for about the same price.  1) Will I still be able to charge the higher capacity batteries with the charger that came with the lower capacity ones?  2) Will it charge them to their full 2500mah capacity?  3) Will it be able to detect when they are fully charged?  4) Will it give a false positive and think they are fully charged as soon as they reach the 1600mah of the original battery packs?

Question by etcmn   |  last reply


Mobility scooter maintenance

I have a Monarch Ryder mobility scooter and I need to occasionally pump up the tyres. The problem is that I live by myself and it is very painful for me to bend down low enough to attach the hose to the tyres in order to pump them up. I have been going to my local garage and they have done it for me so far, but I want to be able to do it myself. I have considered investing in a ramp but I have no way of supporting the top end. I did think of getting solid tyres that never need air, but I've been told that this would make the ride very painful for me as every bump would be amplified. Is there any sort of long hose I could permanently attach to each tyre that I could secure higher up on the scooter when I am not using it? Does anyone have any other ideas? 

Topic by cguide   |  last reply


How to choose the right capacitor for Harbor Freight AC Welder to DC Welder conversion? Answered

I'm watching this series of videos about improving a cheap harbor freight welder. Right now the step is converting the AC to DC. It seems like the guy is just using whatever components he has laying around or that are the cheapest but I want to make sure to get the most power as possible. Here's the AC to DC conversion video:  https://www.youtube.com/watch?v=NoYN4vx1WU8&list;=PLd_DTtq1stJJ4C0qlUnxqBvrfLXLKDyYr&index;=1 Here's a link to the Harbor Freight page with the welder specifications: https://www.youtube.com/watch?v=NoYN4vx1WU8&list;=PLd_DTtq1stJJ4C0qlUnxqBvrfLXLKDyYr&index;=1 It says on the specifications page that the open circuit voltage is 26 volts, does that probably mean that that's the max output voltage at which the welder operates? Anyways, here are my questions: 1.Can a capacitor be fully charged by a lower voltage than it's rated for? For example, the modification in the video uses a 50V capacitor to store charge from the transformer of the welder, which I'm assuming is a 26 volt or less source. Will it still reach it's 46,000 microfarad charge storage potential or does the charge storage potential vary based on the charging voltage? In which case could the capacitor store more charge at a higher voltage, a lower voltage, or wouldn't it make a difference? 2.For the rectifier, assuming the max output of the welder is 120 amps at 26 volts, I am thinking that the guy in the video should have used a rectifier rated for at least 120 amps, probably somewhat more than that to be safe. But instead he is using a rectifier rated only for 100 amps at 1600 volts. That's it. Basically what do you think of the modification. Are those components in the video adequate, the rectifier and the capacitor, or if doing this modification would you have selected different perhaps higher rated components. I have a habit of thinking that I'm too smart to follow instructions exactly and then wondering why things go horribly wrong when projects, recipes, etc. don't turn out.

Question by avocadostains   |  last reply


heating coil advice(resistance wire)

Hi, my name is david. im working on a project, for a device that is roughly .25-.5 inches long. im trying to find the right material resistance wire for the application. the components are submerged in coolant to maintain a low temperature. i wish to have a resistance wire of some kind wrapped around the components to heat them to about 90 degrees as quickly as a possibly can, for only a brief time(fractions of a second) i am using a variable power supply to determine my power needs. im hoping to be able to send a quick "signal" through the resistance wire, and use heat as a sort of input/output system. the internal components will melt at temperatures above 100 degrees.  so regulating the temperatures is key.  now obviously since they will be submerged in coolant, the resistance wire will need to heat to higher temperatures in order to heat the other components. ive been doing some research on nichrome and kanthal wire. but from what ive seen so far, it almost heats up to quickly, to higher temperatures than i require. it is hard for me to do the calculations, since i dont know how many watts/amps etc i will be using.  so to recap: temperature required about 90 degrees. (as quickly as possible, "flash heating" to 90degrees would be great) length is .25-.5 inch (the size will actualy be determined by the resistance wire i would prefer it to be as small as possible but i could make the module larger if i have to) variable power supply to determine my power needs(preferably the lowest possible power usage to conserve battery power) any suggestions on an appropriate material would be appreciated. i dont mind testing out different materials. i just dont want to spend thousands of dollars buying a little bit of everything and testing each one out one at a time. >< some experiments have suggesting silver coated nylon, but requires 20watts and a pretty sizable heating time. the heating coil will most likely have direct contact with the components, unless it is required to provide space between the coil and the components to heat it appropriately. i would prefer direct contact though to make the modules as compact as possible. currently the coolant is being pumped continuously through the whole system, but ive been working on plans for a valve to interupt the flow of the coolant during cycles where the coil is activated, if the need arises to keep the coolant from preventing the resistance wire from heating up appropriately. 

Topic by DavidW433   |  last reply


Is it cheaper to pump water or buy it?

Considering a height difference of say about 15 feet would it likely be cheaper to pump water from a lower elevation (such as a creek or pond) to a higher elevation or would it be cheaper to fill the reservoir with city water which is already under pressure. This is all just theoretical but would the cost of running the pump be more or less than the cost of buying the water?  Of course other factors would play in such as the city water being bacteria and sediment free (in theory) but im ignoring them for now.  Any insight would be appreciated since I have no idea of relative costs for either right now.? Edit: Maybe I made it seem a bit too formal but I am just talking about putting a pump in a lake or creek with a garden hose attached vs turning on a garden hose connected to city water.  Im not trucking it in or anything.  I dont have specifics as said but if the answer depends on specifics then that gives me enough of an answer to know that i will need more research when ready and that its not easily one or the other.  Thanks.

Question by kinderdm   |  last reply


Comparative Environmental Friendliness of Internal Combustion and Electric Vehicles

I would like to know which type of vehicle is more environmentally friendly. Electric and hybrid vehicles are gaining in popularity and they are touted as green, but they clearly require more energy and resources in their manufacture due to their battery packs, rare earth metals and electric motors. On the other hand, traditional internal combustion vehicles require fewer resources to manufacture. However, I imagine that it converts fossil fuels to energy less efficiently than electrics because the conversion process is smaller, unlike in large scale power plants (not sure if this is true). Electric === More resources to create (-) Power Plant (Generates energy efficiently?) (+) -> Power Lines (A: energy loss) (-) -> Motion +,-,- Gas === Fewer Resources to create (+) Combustion Motor (Generates energy inefficiently? B: energy loss) (-) -> Motion +,- I'm pretty terrible at explaining this, but is the energy loss at A or B worse when comparing the two systems? For electrics to be viable, it must offset the higher creation cost. Just wondering which one is actually more "green" when you factor in production (disregard cost of transporting fossil fuels to gas stations and power plants).

Topic by crestind   |  last reply


Archery question: What are the pros/cons to having static limbs Vs Ordinary limbs on an English longbow?

I am looking to build, from scratch, (not even a pre-cut board to start), a 6 foot longbow from Osage Orange wood, and I am looking at different designs. People say that a static tip versus a working tip will improve the speed and silence of the bow. However, different people say that it does not increase the performance of the bow, and will make the possibility of twisting the limbs when stringing it that much higher. Below is a pretty accurate basic shape model of what I want it to look like, but without the scrollwork/external artistic detailing. (Copyright to this image goes to Medieval Collectibles. I do not own this picture.) I love the look of it, and the idea of having a completely silent bow is attractive. But I want a bow that lasts my entire life. Does anyone have info on pros and cons? Also, if ANYONE knows where to get schematics/instructions for building a bow like this, it would be awesome if you could show me where to get them. (Pay close attention to the shape of the tips!)

Question by zelback1   |  last reply


Electronics

Http://www.taskled.com/techbflex.htmlI wonder if anyone can helpI want to make a bike light using CREE leds (*4) and have spotted the bflex (see here - http://www.taskled.com/techbflex.html - I was going to go for the UIB2 version) as it has battery monitoring facilities built into it. You set two voltage values v(low) and v(med). There's a connection on the board V(stat). S is the voltage from the battery.V(stat) = 0 if S is higher than v(med) => State 1V(stat) = 3.3V if S is between V(low) and V(med) => State 2V(stat) = alternates 0 and 3.3V between 0V and V(low) => State 3So I was thinking (of displaying this via 2 LEDs (green and amber))State 1 - green on, amber offState 2 - green off, amber onState 3 - alternating between green and amber.I was hoping to combine the LEDs into one bicolour LED. If anyone has any cunning plans or improvements they'd be appreciated.. whatever it end up with though it mustnt use up too much battery power.

Topic by EXM   |  last reply


capacitor bank questions.

Hello all, this'd be the first post i've ever made, and may be in the wrong place....... edit- i guess it was in the wrong place, since no one replied.... so i'll try here.... i'm tryin to make a cap bank from 30+ flash cameras (possible? possible outputs? how do i calculate that?)  and i have some question/problems. is it possible to take a bank like the above and use as a spot welder?   if so, how would i trigger the spark without the trigger becoming the spark gap?  another possible use i have for it is a rail gun...... theoretically, if counter evidence isn't provided by all of you much more tech inclined ibblers a second concern is that the caps come in at least three different micro farad ratings. would one explode if it's rating is lower than the higher ones?  (the ratings are between 80ish to 150 ish (don't remember)) i rather need the weilder for a possible steampunk project that i just bought a bunch of metal junk for....(knowing me though, i'll never get around to doing it....)

Topic by badideasrus   |  last reply


The save button in deactivated in Acura 15.04.6

I am trying to export a G-Code from Acura I noticed when I loaded the file, starts processing and at some point it stops. I can see the support material did not finish processing and the top portion is not complete.Then I make changes to the settings I increased the height of the layer and reduced the density.In other words is a lighter density overall. If i decrease this a lot, Then the software manages to finish the set up proces and the save button comback active to export Gcode.Seems like the large data of the higer density settings runs out of Disk space to create the cash.Does anyone know how can I fix this problem?I remember when I work in Adobe after effects editing videos, the software ask me to reserve a dedicated folder with an specific disk space just for cash, when this folder is full, the software ask you to empty the temporary cash files to make more disk space for more projects.Does anyone know how i fix the space disk or what ever i need to do to allow the software to finish procesing with higher density?Please helpYou can email me to gamelicruz@gmail.comThanks

Topic by gameli97 


Would you guys like an instructable for this gas powered bicycle?

I was wondering, who would like to see a detailed instructable with step by step instructions, lots of pictures, and parts lists for how to make this powerful motorized bicycle from scratch (without a kit)? The motor is a heavily modified 79cc horizontal stroke predator engine from harbor freight. The bike has a top sustainable speed of about 40mph. It also has enough torque to accelerate uphill, take off from a standing start with no pedal assist, leave Lance Armstrong in the dust, and do wheelies even with my 29" tires. Gearing can be adjusted for higher top speed at the expense of having less acceleration and hill climbing power. (Although in all honesty, I wouldn't gear it to go much more than about 45). Other features include an automatic clutch, the ability to get 170 miles per gallon, allowing you be cooler than all your friends, and costing a fraction of what you'd pay for a vespa. If you want me to make an instructable, comment below! Also tell me whether you might actually build one, or whether you just want to see how I did it.

Topic by TheNecromancer13   |  last reply


Can you insulate the primary coil of a Tesla coil?

Hello,    I am trying to build a tesla coil using a new design relating to a thesis paper I am working on. Due to spacial restraints my primary coil will be close to the secondary coil. I know I have seen others use insulated braided copper wire as their primary. I want to stay with 1/4" copper tubing if at all possible so I wanted to ask what affects it would have if I used heat shrink tubing on the copper tubing. I am aware the higher frequency voltage runs along the skin of the tubing since that is least resistive at that point. A for the power and caps I am using the following: three NSTs of which two are 15kv @ 30 miliamps and one 12kv @ 30 miliamps, 13 CD 2000VDC @ .15nf caps on each 15kv NST and 10 of the same caps on the 12kv NST. The spark gap is static for now.  I want to prevent arching as much as possible in the small space. Any advice is greatly appreciated. Some of the information relating to the thesis paper I cannot release due to a serious concern of being scooped before publication.  Thank you. :)

Topic by XsFacade   |  last reply


Electric Motor Tricycle 6V4.5Ah

I bought a riding toy for my son and it's cool, but it doesn't have enough power sometimes.  It's fast enough in the house, but it gets stuck outside.  The plastic wheels tend to slip on rough surfaces and inclines, but I can address that issue at the wheels/tires to some degree.  However, the battery that came with it is a 6V4.5AH/20HR sealed lead-acid rechargeable battery (It has F1 contacts, so unless I change or adapt the wires/connectors, I think I need to stick with a battery that has these).  The AC-DC adapter has 6V DC 500mA output, but I think I could get a UNIVERSAL AC DC ADAPTER {1.5V 3V 4.5V 6V 9V 12V 500mA} that would work with a new battery. I'm hoping that I can increase the power noticeably but safely.  One constraint is the width of the battery area inside the "engine" compartment.  It fits the present battery (1.75 x 2.75 x 4), but I'll have to mod the compartment to fit a replacement that's more than slightly bigger. I've seen some 12V4.5AH batteries online, but most are larger in every dimension. Am I even on the right track thinking a higher voltage battery is what I need?  Could I use an NiMH or Li battery/batteries instead? What's the easiest, safest, cheapest route for this mod? Thanks, Dan

Topic by danhorowitz   |  last reply


Wall mount a non-VESA monitor?

I have an ASUS ML248H 24" monitor that I want to mount to higher to remove the footprint from my desk and to have a better viewing angle since I usually lean back so I have to look "down," compared to my body position, to look at it at the level of the desk. The problem is that it doesn't have any place to attach an off the shelf wall mount. The only place to attach anything to it is where the base/stand is connected, and it's a funny thing that would be really difficult to replicate (see picture) I've looked through many of the ibles in the subject and nothing seems quite right so any suggestions would be great. The only thing I can think of so far is to use the vertical part of the original stand which would add a couple inches to the depth and act like a lever, multiplying the weight on any thing holding up the monitor, but adds more options for attaching stuff in the form of one vertically oriented bolt hole at the opposite end of the one that attaches the bracket to the monitor, as well as four smaller holes at roughly 30  degrees to horizontal (see pic #2) I was thinking of something like a pipe coming up off the desk or out of the wall but can't figure out how to connect the two pieces so that I can still have swivel and tilt adjustment.

Question by siamonsez   |  last reply


Amatuer experiment Contest! How high can an aquarium airpump pump water? Mini airlift pump.

I believe that many bubble pumps for aquariums can bubble the air about 2ft deep under water.  So if you use the air bubbler as part of an airlift pump, how high can you pump?  Here is a link about airlift pumps http://www.animatedsoftware.com/pumpglos/air_lift.htm (unfortunately the wikipedia airlift pump entry is commercial spam). Anyway, the aquarium air pump I used produces about 2 liters of air per minute (so not so much). So here are the contest rules.  Your airlift pump has maximum submergence of 2 ft.  You must use a T-Joint to introduce the air and you use an appropriate pipe diameter to airlift the water higher. The height pumped is measured from the top of the water in the water reservoir to the top of the airlift pipe and the submergence is measured from the top of the water in the water reservoir to where air enters the T-Joint. So, winner and Instructables world record holder is  the person who pumps water highest under these conditions. I will start with my example. Thats pretty much as high as I will go but if you have a suitable area, I think you might beat me! Competition is ongoing. Best of luck Brian

Topic by gaiatechnician 


Torque to linear thrust through lead screw

Hi,I am trying to figure out maximum linear force I can produce with an electric motor through use of lead screw and nut. I have come up with an equation which seems correct but resulting forces are way higher than my intuition believes is correct.I tackled the problem from the perspective of energies:F' * p = M/r * 2*π*rlinear force * thread pitch = torque / radius [M/r = force at radius] * circumference of lead screwF = 2*π*M/p * (1-k) //k stands for coefficient of friction between lead screw and nut)Radius falls out of equation, which seems fine as force is provided by torque, which is radius agnostic. I used a 7€ stepper for source of torque which can provide 0.42 Nm of torque and a lead screw with 8 mm pitch and 4 mm radius, I assumed 15% losses. My equation tells me that such system can provide 280 N of force, which seems wayyy too much for a cheap motor.I have attached a python code that calculates linear force in case it helpsCan someone tell me if my equation is either correct or flawed?

Topic by ptkrf   |  last reply


How strong is sheet steel? I am thinking of a rugged Kindle Case?

I want to make an extremely strong case for my kindle, the kind of case where I could sit on it and not cause a problem. I'm also worried about the corners of heavy books hitting it right in the middle and breaking it through the case. I have thought about sheet steel, flattened PVC and wood. Wood adds a decent amount of thickness to be rigid enough, and I wouldn't know where to buy thin hardwood planks. PVC I don't believe is all that rigid once it's been turned into flat sheets. Sheet steel is readily and cheaply available on Ebay between 0.18mm (0.007 inches, or 36 gauge) and 1.7mm (0.06 inches, or 15 gauge), and probably higher. I don't care about the weight as much as the thinness and strength/rigidity, so I thought sheet steel might be the best option but I've never worked with it. Suggestions? Edit: I would add some sort of shock protection, ie: neoprene, but it's not dropping that I'm worried about. The design would be two flat pieces sonnected by a fabric "hinge," similar to this: http://www.amazon.com/Marware-Atlas-Kindle-Touch-Cover/dp/B005HSG3L0/ref=sr_1_6?ie=UTF8&qid;=1340375705&sr;=8-6&keywords;=kindle+case I would add raised edges surrounding the Kindle on the "bottom" piece of metal, so that the two pieces wouldn't squeeze the kindle between them when pressure was added.

Question by ballardst   |  last reply


AC MOT Welder Voltage Issue

Hello everyone, I've been working on an arc welder based on instructables like https://www.instructables.com/id/Small-110-volt-arc-welder-NYDG/ but I need some advice. Most tutorials on here suggest two paths to success, either winding two MOTs with as much 10 gauge wire as possible, hoping that the voltage output in series will be close enough to 40V, or using multiple small transformers, also in series. The problem is, all this series stuff really cuts down on the available amperage, so I'm wondering if there's a different way to get high amps and volts simultaneously (obviously without surpassing the available 2400 Watts, energy in = energy out). I think I have a way to make two MOTs which run at low voltage but high amperage also have high voltage. I've made a high frequency circuit to assist in starting an arc, which you can see attached (it works phenomenally, and I've been able to make it run on 1 amp). Since the output on the HF part goes through a torroid at the far right (where it meets the welder's output), would it be possible to wind the torroid with, say, 5:20 turns, to basically take the 120A (10.8V) I get from the parallel-connected MOT transformers and overlay a low-amperage but higher voltage on it, to make arc start/run easier? The welder just won't run at 10.8v, so other than rewinding the secondaries, what about jumping the voltage up a little via the output torroid?

Topic by reakter 


Wireless Power Transmission

Nikola Tesla's grandest vision was the transmission of large amounts of power without wires. His work in this area was abandoned by his contemporaries, and there is still much debate over if it could or could not work. I would like to hear your opinions on this. Do you think it is possible? Would it require only one transmitter, or several, spread across the globe? Would it be safe? Would it be worthwhile? Could Tesla's original spark gap circuit been sufficient to drive it? Or would it be better to use vacuum tubes or solid state setups? Would the operating frequency be very high or very low? Pictured below is how I think Tesla may have done it, based on the information I've seen. It's a bit over-simplified, but to the best of my knowledge, it covers most of what is needed. Please note that, although the transmitter terminals would be at a much higher elevation than pictured, the receiving terminals could stay at a relatively low elevation. This link is to a YouTube video of someone using a small Solid-State Tesla Coil for wireless power transmission: www.youtube.com/watch Edit: I had orriginally imagined that the system would work by capacitive coupling between the Ionosphere and the coils. Afterwards I realized that electrostatic capacitive coupling will decouple after seperation between two plates is greater than 1/2 the wavelength (or, at least in theory), so I personally abandoned the idea. The only problem is that I can't imagine how power would be sent to airplanes. Also, this is a very good read on the subject, from a very interesting site: www.teslaradio.com/pages/wireless_102.htm

Topic by ElectricUmbrella   |  last reply


Anybody want to model "reflux" in the circulatory system? Physical model or computer pipe model!

My wife just had an amazing success when we went down to Newport Beach, California to get venoplasty to relieve many of  her symptoms following a stroke.  http://www.youtube.com/playlist?list=PLkzXlmAwZTZfQ01RnN-8Ip5lUz0HrNWzN  We pay for national medical insurance in Canada and this treatment is not covered.  (Even though it clearly works, )   One road block is that an expert doctor here could not find any evidence of reflux in blood flow to or from the brain.  (Some MS patients have damaged valves in their neck veins).  Now, given that each heart beat raises blood pressure from 1.5 psi to 2.3  psi about once every second and that valves are actuated by the blood flowing backwards, I find the "expert doctor's" results impossible to believe.  I am not totally without knowlege in that area either because I made a low pressure airlift pump this year  that has a much higher lift submergence ratio than the normal ones.  (The airlift in a bucket one). I was told that the maximum  lift to submergence in these things was probably not much more that 10 to 1 but I managed to get over 20 to 1 lift to submergence primarly by reducing reflux.    Also, I observed that the effects of this reflux can extend conciderable distances from the "valve" itself and are different in small tubes than in big tubes.  Therefore it is possible (Likely even) that a damaged valve in a persons jugular will have its primary effect in a capallery somewhere in the brain up to a foot away from the damaged valve.  So if someone made this model, I think it is likely that they can contribute to the rapid advancement of medical science!   Brian White

Topic by gaiatechnician   |  last reply


Getting more power from a quartz clock movement

Using a transistor to boost the output from a quartz clock to drive a larger motor in steps. Is the idea sound what would I need? Having read a couple of instructables on equitorial drives, I found myself wondering why you couldn't just use a quartz clock movement to drive one? They don't produce much torque is the answer to that one. Why not? I took one appart to find out. The gear chain is very flimsy moulded polyethylene, or maybe nylon. the power comes from a tiny armature that makes 1 turn a second in 2 pulses the magnetic pulses are provided by a little cuircit board with the quartz ossilator on it. Here endeth my actual knowledge. My knowledge of electronics is minimal give me a good set of instructions and I can build it (unless its a joule thief but thats a different matter) but don't ask me how it works. My limited understanding of a transistor is if you put a small current or voltage across 2 pins you can get a bigger current or voltage to flow across one of them and the third, something like a relay. I was thinking if I took the out put from the quartz cuircuit that provides the magnetic pulses and used it to trigger a transistor to pulse a higher voltage and current through a small 3 pole motor kicking it around 1 pole per pulse. The motor I have a salvaged and rebuilt in an earlier instructable runs on 3V and draws 0.2A when not under load. the largest motor I have to hand is a big 7 pole one designed to power model planes or cars draws up to 15A on 7.2V the timer cuircuit for that one needed 3 Mosfet's in parralle so I'm guessing thats not possible.

Topic by Stan1y 


Ceiling fan generator mod to the max

I stubled upon several mods to convert a standard ceiling fan into a more or less usefull generator.So if you are looking to go this route then I might have some nice improvements that can be implemented.People like these mods for some weird reason, despite the fact that it requires quite a bit of extra work to make them weather proof.However, when it comes to the fundamentals then to me it looks like some folks out there are missing out.On the available power that is...Always the first step for a mod like this is to replace the induction ring with a lot of magnets.Second step usually is to remove a lot of the coils, especially the inner ring.Now, these two stator designs are common for fans with two speeds.Those with three or even reverse might have a different configuration!Lets start on the magnet part:The recommended way of placing the magnets is by creating an air gap as small as possible - makes sense.But then it is always the same amount of magnets as there is coils - and the spacing is also the same as for the coils.In the general generaotr design world this configuration is prefered as it allows for the best performance.If you dare to go a bit further and cosider how the magnets react to the stator configuration then you might want to consider a different option.You see, these two sets of coils for two different speeds mean just one thing:A different amount of poles is created, with the outer ring having more poles than the inner ring of coils.The core is split around the coils, not just to allow the windings to be made but also to provide independent paths for the magnetic field - resulting in the two pole configurations.Amounts differ by diameter, power level, manufacturer and so on.What is always the same is that the inner ring has less coils and that the outer segments of the poles created have even spacings.In the normal mods you see posted these gaps in the core for the outer ring are closed by inserting lamitaed pieces from some old transformer.And you end up with ONE usable coil configuration and ONE power output.The slightly advanced mod uses the inner coil to add some load depending on the speed to prevent spinning out of control in high winds.If you try a normal DC motor with permanent magnets than you will notice the strong binding forces, it is like the rotor sticks in certain places.The better ones use and uneven configuration to reduce this binding effect ;)In my mod the magnets are selected in size to almost be the same length as two stator poles next to each other.This allows for the best induction while still allowing "to experiment".Bringing the magnets and the coils into play...As said an exact match of the number of magnets to either coil ring is not ideal.The prefered option is to go somewhere in between.For example:Outer ring has 18 coils then the inner ring will have 9 coils - exactly half.360° divided by 15 make a nice 24 degress per magnet.But with 12 magnets you get an even 30°, which is far easier to deal with.16 magnets at 22.5° is another option.So, what does that exactly do for us?The bad thing is we get slightly less performance if you only see the standard mod with one coil ring.The good thing we get far lower binding forces and through that the thing will even spin in very light winds.Adding both coil rings with a suitable rectifier however results in a pulsing output of two sine waves.With just the rectifier we get a ripple that is easier to deal with through a capacitor.The extra power available is in the range of about 40% and make more than up for the "reduced" amount of magnets.Going the extra mile once more ;)Having created a much fancier ceiling fan mod now you might wonder if there is not a way to get even more out of it.And there is.For example by utilising a gear system or belt to get a far higher rotational speed on the generator than what the blades would provide, prefably then with quite big blades too and an automatic break for high wind conditions.With the reduced binding forces the generator will be happy to spin at quite high speeds in low winds.Downside is that you will need to build a far more sturdy bearing housing.In return though you get more stability and durability.You can do the math yourself based on the number of poles per ring and magnets to get the output frequency based on the RPM's.Perfect would now be to use a switch mode power supply configuration to directly transform the provided output into a stable DC per ring.And yes, it is possible to use mechanical systems to provide a fixed output speed from the blades to the generator - but way to complex and lossy!Lets do some lame math with no regards to realities:If the original fan would spin at 100 RPM at full speed than we could say our generator should provide the mains voltage at about 100 RPM.Keep in mind we utilise both coil rings and not just the high speed one!Geared and with the blades spinning at 100 RPM we might get as much as 1000V from this little generator....And even with the lower amount of magnets we migh see frequencies above the 500Hz range.The good thing now is that normal iron core transformers can still operate at these frequencies.A bit lossy in the upper range but acceptable for the purpose.Put simple: A 10 or 20:1 transformer per coil ring would provide us with a far more suitable output voltage and much higher amps.If you made it to here than you certainly wonder about other magnet configurations.Checking the stator configuration you will by now realise why I selected the magnet lenght accordingly.The magnets "activate" one coil after the other.The spacing between them means there is always some overlap where the magnets only cover one half of the stator for a coil.This is ok because we don't really have to worry about the resulting messy output.Ideally though you would want to have a magnet activate both coils, the inner and the outer at the same time.What we did though was to make sure that at no time more than ONE magnet fully covers more than ONE coil!It is the best option to cover both coil sets while minimising binding effects and increasing the avialable output.To go the last step you would need to invest a lot of time re-winding all coils :(You don't want to do this unless you have the means and no friends and family that might miss you for a few days....I found a far simpler way to change the coil configuration, although it is not as good a re-winding.So let's go full scale shall we?Ceiling fan reconfiguration!If you take the usual 18 to 9 configuration than one thing jumps to mind reight away: 3-phase power!Cutting the wire that goes from coil to coil might not always be possible and if it is then you need to know how to handle it.Magnet wire can be hard to solder.Burning the coating off results in corroded copper that is even harder to solder.If you are lucky though than a reall hot soldering irong will be able to melt the coating.The flux from the solder will start to cover the wire from the cut and the solder will follow.If not then using some fine sandpaper and time is the other option to remove the coating...Ok, you seperated all coil and have two wire ends per coil?I hope you did not cut off the ones going out to the actual connections to the outside world ;)Properly solder each wire end and take your time to check it is really proper and not just a few spots.Mark or number the coils on the rings!For the inner ring we have 9 but need only 3, so we start at one connection to the outside world and check if this connection is on the outside or inside of the coil.For this example I assume you picked the one that goes to the outside of the coil.Connect the inside wire to the outside wire of coil number 3, assuming we start with 1 here ;)From the inside wire of 3 you go to outside of 6 and the inside is you first new output connection.Do the same with the remaining 6 coils and where needed add the required output wire.It really helps to have wires with three different colors here, one color per new coil set.Note which color corresponds to to the three coils used!!!The outer ring with 18 coils is sightly different here.You see, we want a "flowing" magnetic field that makes best use of the new coil configuration!We can not simply bridge them in any way we feel like without considering how this might affect the electrical side of things.As we now take the approach of a three phase system it makes sense to use a more suitable magnet configuration as well.So before go to the outer ring of coils lets have a look of the best option for the magnets first:The stator packs are evenly spaced in our example and will alow us to use 18 magnets.This provides the best performance with the downside of a higher binding effect, but we need this configuration to get the best possible output.As said at the start I selected magnets that are just shy of being the same length as the corresponding stator segments.In a "free" setup these magnets would now be quite hard to place in a makeshift ring.Even harder in the original casing.A 3D printer certainly helps but some common sense too ;)Wood is easy to work with and if you select the right stuff than making a suitable ring to hold your magnets and attach to the drive system metal parts is not too hard.Bar or brick type magnets can be quite easy be utilised on a wood setup :)The key is that you add Flux Capacitors - sorry couldn't help the reference to Marty....What I mean is to add some magnetic material between the north pole of one magnet and the south pole of the other.Lets say your magnets are 15mm long and have a spacing of 5mm.Then a little plate of 12mm would be next to perfect.This plate needs to connect the magnets on the backside, the side facing away from the coils.Use a dremel tool or what you have to first create slots for the metal strips or bars, then the same for the magnets.Glue in the metal first and once set add the magnet, making sure the always go north to south with their alignment.Ok, and what does this do for us?I hope you are not one of these persons who starts building while reading...What we created now is a shortcut for the magnetic forces.The field between the magnets is severly compromised in terms of being usable for the coils.We do get a much soother run though...I only did that to have some fun and check if you paid attention - sorry :(What we really want is an effect similar to what you see on a loadspeaker magnet that is still in its metal shielding.A ring magnet with one pole on the inside and one on the outside is used here.The shielding provides a path for the magnetic field that is not going through the speaker coil - hence the little air gap for the coil.If we do the same then our efficiency will be going up quite a bit.Take two identical steel parts, like some butter knifes, and prefarbly a force gauge.If you try to pull your magnet at a 90° angle from the blade you will get a certain reading for the required force to lift it off.Most people now think that this would be the max a magnet can hold.So take the other knife and place the magnet between them.If you pull the knife off with the gauge now the reading will be higher than what you get from just the magnet ;)Taking that to our model and keeping the field lines in mind we now know that we could even use slightly longer plates if our magnets happen to be a bit short :)Just place them right behind each magnet !Back to the outer ring of coils....With 18 magnets we get an even system for both coil rings.However we want to make sure that our output waves are syncronised and not at random order.We need to combine two coils to be back on a 9 coil configuration as on the inner ring.The other option is to provide two sets of outputs for outer ring, resulting in 3 3-phase outputs.Both have their pros and cons....But if you check the 18 magnet configuration ina ction over the coils it becomes clear that combining two coils the usual way is possible but also that our inner ring does not get a proper north south action from the magnets!Only the outer coil ring works properly!For the inner ring we never get only a north south combo, instead a lot of mixes.Did I mention to read first? ;)Of course we can only use 9 magnets in our configuration, but at least I did not traick you on their size....You see, we need to account for the fact that the coils are not just evenly spaced but also that all configurations in terms of coils to stator pack are doubles or halfs.Makes a lot more sense if you know how these asyncronous motors work :)With 9 magnets we actually get both inner and outer ring coils activated properly.Plus we now have the benefit that there are always twoouter coils in sync with each other.Means apart from the same way you wired the inner ring you make this addition to the outer ring:"One" outer coil is created by going from one coilinner connection to the outer connection of the second after this, skipping one coil.The resulting output is again just 3 phases but with double the output voltage.The key is to again take notes of how you connect and wire the coils - and the colors used for the output wires!Let me give you an example for the correct order:I we take the number 1 coil on the inner ring then coils number 1 and 18 would be next to it on the outer ring.You want to combine 1 and 3, 2 and 4, 5 and 7,....And you want the resulting three coil packs and wires colores to correspond to the inner coils in the same order!That is true for the always same way of combining coils from the inner to outer connection - or the other way around but never mixed!Ok, we have done the magnets and the coil configuration now properly, no jokes this time!With two simple 3-phase rectifiers we get two DC outputs that can be combined or used seperately.As we end up with roughly double the output voltage on one output but all coils are the same it makes sense to treat them independly.For those who wonder why:If you add a load than one coil system would take a higher loading of it.Meaning while one coil set is stll fine the other will already start to overheat - if the load is too great.So we use two rectifiers with some filtering.In the basic form just a really big electrolytic capacitor of suitable voltage or a full LC filer system with multiple stages.Either way we can now utilise some better DC-DC converters to get going.Considering the equal max watss the coil rings can handle it make sense to include some current limiting.A good converter will provide this option.Both converters can now set to the desiered output or with some added protection diodes and adjusted properly to the same voltage combined for just one DC output.Compared to the standard mod of removing coils and bridgning stator packs the resulting output power in overall Watt will now be about 40-60% higher - depending on the model and quality of parts.Special words of wisdom:Consider the orignal max speed of the fan when used as intendet - see this as a theoretical max output that equals your mains voltage.Just ignore losses and such things - better to be safe than sorry.It becomes clear that it quite possible that your output will be far higher than mains voltage and that you need use transformers for the two 3-phase systems so you can use standard DC-DC converters, which have a max input voltage of around 50V only.This means your converter must be able to handle the higher amps!The fan might have only used 100W or less than 500mA but at high speeds and a ratios of lets say 10 to 1 for the gearing high wind speeds might get it up to over 5 amps on the transformer outputs.Please do the math first for your gear system in relation to the max wind speeds you want to use with your blades!If in doubt use a converter that has some reserves to offer, especially if you aim to charge batteries as quickly as possible.The most vital part however is to ensure that all previously cut wires are isulated properly!!!Magnet wire of the standard kind is good for about 1000V max, so don't drive it higher!Heat shrink with a hot glue liner is prefered but hard to apply in these thight spaces.Since nothing moves consider using long enough wires for your connections so you have enough space to solder without affecting the heat shrink tubes.Liquid insulation or rubber is the last option and should only be used to finalside the heat shrink security measures.Best option once all is confirmed to be working fine would be to make a custom mold and to fully enclose the staotr pack and wires with casting resin or an insulating casting mix.Make sure to keep the output wirese free at the their ends ;)What if I don't want to build a complicated three phase rectifier and just use a single phase system as it was?Firstly chances are your coils are already connected in a three phase configuration, just all in series.But working out a suitable magnet configuration to suit this is much harder if you want to use both sets of coils.In a series configuration like the original you also have to accept the losses from these connected coils.The higher the overall resistance the lower the possible output ;)Main problem however is to get the magnet working properly.The standard 9 or here even 18 magnet configurations still works, especially with the added shielding from behind.But the coils also produce a magnetic field, which grows with the load.Means that an top of all you also have the coils working against the magnets and create even higher losses.Explains why the simple folks prefer not use the inner coil set if they go with a single phase system.So either accept the losses and just use the outer coils or do it fully and get far mor output.And by the way: a 3-phase rectifier modlue is only a few cents more than a standard bridge rectifier ;)Ok, and why do I bother to write all this?People like to tinker but most don't really invent.Following some simple instructions is easy, trying to work it yourself much harder.The reward however is that you actually start to know what you are doing :)And what works for a ceiling fan can be used for these ring style washing machine motors too ;)Anyways...We need to get back our roots.Start thinking for ourself again, work things out instead of just looking them up.If people would be aware that a simple ceiling fan could provide about 3 times the output power of its rated installation value instead of only just about half......Super strong magnets allow real output even without re.winding all coils.And what works here works for other things too.We only learned to use magnets in a striaght way because we can not bend them.But we can bed the magnetic field lines to our advantage!The simple shielding used in this mod is nothing more than a shortcut to enhance the field strenght where it is is needed.By a simple coil modification we basically bet two electrical generators for the price and size of one.Apart from stating how easy it would be to place multiple stators and magnet rings into one generator the magnets itself also allow for even more output.If you ever played with hook magnets or speaker magnets then you know how much stronger they are compared to just the magnet once they seperate after hours of fun for you.Imagine you would replace the single bar magnet with two block magnets that are joined by a magnetic shunt like out simple shielding before.If the magnet blocks now would have a slightly smaller footprint than your individual poles:Imagine you create a hlaf ring shaped magnetic connection between the two blocks that also goes aruond the outer perimeter up to the outside of the magnets surface?I mean the surface facing the stator poles?Damn your imagination is good, yout it right away!Of course we would then have a magnet that allpies its full strength focussed onto each pole of a coil!And of course the resulting field would be far stronger than just using the magnet blocks itself and still significantly higher than just adding a shielding or connection between them.The affect of the next coil coming is also drastically reduced, which in return also increases the efficiency.In terms of numbers:If a fixed neodymium magnet would provide us 100$ field strength as the base point with no shielding (just the magnet blocks alone);A fully shielded and connected system, like in a hook magnet combined with a U-style magnet, would reach above 400% here.....Adding witchcraft to the mix ;)Although I know better I just assume some of you have now a working double-three-phase-ceiling-fan-generator.And that would mean you also have some fans to spare from your long experiments.Modern ignition coils seem to have nothing in common with our ceiling fan or resulting generator.So why do I try to use them anyway?For the ignition only one polarity is prefered so the spark works and travels as intendet.Means the "wasted" energy from the othe half of the pulse seems to be lost.The electronics do a lot here but magnets too ;)The core of the coil has magents at either end, turning it into one long magnet that still has the right properties to act as high voltage transformer system with the coils.The coil appear to be pre-loaded and with the ignition pulse it has to overcome the magnetic field pre-set by the magnets.And when the electrical impulse is off the same magnets also accelerated and increase the resulting fall back impulse - which provides the spark.Unless you have a suitable laser cutter or simlar cutting tech available somehow it will be hard to modify the metal plates of the stator.But if you could...Imagine you could add magnet inside the plates that are inside a coil.The same pre-loading would happen.Does not really help in terms of adding outpur as our rectifier would suffer badly here.It does give ideas though...Shielding works fine for the magnets, same for field shaping.Electromagnets use the same techniques...So why not use some leftlever transformer cores to add more "shortcuts" for the coils?Strips of transformer core sheets added either side of the coils increase their field strenght and result in better output!Three packs either side of the stator pack are usually no problem.Now take your leftovers and do a standard mod.Compare the max output on the same windmill with what you get from my mod(s).The only real magic I used here is that I actually bothered to combine multiple and already used methods to drastically increase the available output of an otherwise utterly useless generator mod ;)Warnings:If you take the above mods serious and to the their extreme than it is imperative to make sure you have safety measures in place!Assume the lowest rating for the magnet wire and if in doubt stick with a max output voltage of 800V.These mods are potentially lethal if you don't follow what is common sense to everyone dealing with high voltages for a living!Most people will start without any gearing or belts and use the wind directly.Even here it is easy to get far higher RPM than what the thing ever did under your ceiling.Without some fixes you will need transformers to reduce the output voltage accordingly.Only other option is to limit the max speed to what your DC-DC converter can handle.Making mistakes with mangets can cost you a lot of time and work, make sure to mark their poles somehow to prevent putting them in wrong.If in doubt then double check!Always keep in mind what the magnet wires and your connections can handle!You don't want any arcs or overheating.Some added electronics to monitor wind speed, rpm's, load and temperature of the coils can turn out vital once you upscale.Before letting your new generator do its thing make sure you tested all to the max!Use a drill or so to speed it up and check the limit regulation for the converters.Measure the actual volts and amps going through your coil sets at assumed max speed and max load.Monitor the coil temp while doing so to ensure nothing is out of limit!You are kidding me here right?A scrap ceiling fan shall provide more output as a wind generator than what was used to spin it as a fan?And of course I need not one but two 3-phse transformers...Pretty clear it is all a fake because nobody could replicate any of it unless limited to what the converters can handle...Didn't I say to think outside normal restraints already?A single phase transformer uses two coils in the most basic configuration.For example one side for 240V and te other for 12V.But some of them are more efficient than other ;)A 3-phase transformer uses 6 coils, two for each phase.And there are plenty of standrad transformer cores out there that would allow us to use this configuration.The worst being the MOT, or microwave oven transformer.Very lossy for a reason but good as an example as these have three core stems ;)Now that you see that you will that a lot more transformers actually allow you to replace the two coils with 6 ;)Ok, but why not use a rectifier first and not use a transformer or two at all?The resulting output voltage will without a gear REDUCTION be much higher than what a cheap DC-DC converter can handle.And at such speeds the effiency would be very bad too.You would need huge capacitors of good quality to deal with the now more impulse like output.And considering the primary side of the transformer does not require anything thicker than the wire on the coils of the fan...Not hard at all to find some suitable tansformers to salvage - or to use some nice ring transformers ;)No kidding around, just facts and possible options you might want to explore.Does that now mean I get free energy?Sure, if you mean you get the free nergy from the energy of the wind at no cost.No if you think a ceiling fan could ever power your house.Internal resistance, size and wire/connection properties set our limits.Not to mention that they are designed to be dirt cheap.If you are in a windy region and assume a realistic 300W minimum output from a 100W fan then adding more stage multiplies this.These fancy upright windmills are not just powerful but also would allow to use one modded fan either end.If big enough and with enough wind force throughout the year you could just add a second or third stage to ech end.With 3 on both ends the resulting output would then be suddenly 1.8kW per windmill....And all from scrap parts with only the costs for the magnets...No wind? Then use water....None of it? Get some greyhounds and build a big hamster wheel :)You get the general idea I hope...

Topic by Downunder35m   |  last reply


Where is the induction kettle or hot water system?

No modern kitchen these days is complete without at least a single induction cooktop.Convient to even place on the table to keep things warm but also nice to have 4 or 6 "hotplates" to cook on that are actually not getting hot at all.When it comes to efficiency induction cooking tops all others as no heat is wasted.Which brings me to the point...A single cooktop goes now often for well under 50 bucks.Although the base might end up slightly higher than a normal kettle I fail to see why we don't have induction kettles in our kitchen.Why wait 12 minutes to have the thing boil if you can do it cheaper and faster?Way more convinient too as there is no pesky contacts and heating elements anymore, no failure due to leaks either...But what really got me wondering is the hot water systems or heating options like prefered in Europe.Here you have a central "boiler" so to say and water circulates through valves into finned radiators, usually located under windows.We have oil filled radiators of this kind as free standing units that are now being phased out because they waste too much energy with their heating elements.Same story for just hot water :(On demand systems are getting more popular now outside Europe but still the common solution is to have a few hundret liters of water in a tank that is kept hot no matter how much of it we use.Be is gas or electric both types have their drawbacks and to get ahead of the corrosion that always kills them we now opt for expensive stainless steel tanks...Using induction it would be very easy to have a fully sealed tank and to actually only heat what needs to be heated without wasting too much energy.The "heating" element could be just a steel plate inside the tank with no connections to the outside.The gap between wall and element doubles to make the water circulate.And changing from a fixed timer to a temperatur control system to turn the induction element on and off is not hard either.Do you have an induction based hot water system, heater or maybe kettle already?Would love to see it...

Topic by Downunder35m   |  last reply


Construction ideas for this concept?

Recently, I have been working on a gas 'vaporizer' that evaporates gas before being fed into an engine. During my short-term experiment, I found that this saves ~70% (+-20% for crudity of measurement.) This works because the vapors will burn more thoroughly and cleanly, leading to higher apparent efficiency. Below is a basic diagram of how the system works. You can see there is a container that is half-full with gas, and a hose goes down with many small holes. As the engine's compression draws a vacuum on the container, air will come up through the holes. As it rises, the gas-air surface area rises dramatically, leading to the vaporization of gas. To further increase the surface area, I also added a felt liner on the inside to allow the gas liquid to rise and evaporate. The final mixture ends up very rich, so to compensate, a 'T' fitting has been added to allow air to mix in with the vapors/fumes. Some valves have also been added to control the air inlet (similar to a 'choke') and the amount fed to the engine (similar to a throttle. In fact, it is possible to use the original throttle or choke as a throttle on the carburetor on my tractor!) The problem is: My original design utilized a plastic folgers coffee can, and the flimsy plastic top was hot glued to a thicker plastic cutout for strength and support. Since most glues will dissolve in gasoline, including hot glue, it could not be used. most did not hold anyway. I also tried JP weld plastic cement and it did not hold at all. I had to trash this build. I did, however, get enough use to run the tractor for several minutes while testing gas use. I found that the tractor used nearly twice as much simply running on gas than the fumes. I did not have the float valve and electric pump hooked up with the prototype. Also the 3/4in housing I used may be a bit constrictive and also seems to get slightly damaged by the gas. It will not be a long-term solution.  So I need to redesign the project, and I am thinking of using a 1-3 gallon bucket that is sealed or a gas tank. I need good almost air-tight seals on everything. I am asking for any ideas related to the construction of this device and any tips you may have.

Question by -max-   |  last reply


Heated print beds - are they overrated gimmicks?

For years now I use my old, trusty Mega Prusa with the bare basics in terms of hardware. But basically every new printer out there comes with heated print beds and most users "upgrade" to one to get better quality prints. So I started to to check the reprap forums and other websites to find out why a heated would be a "must have". Quite a simple task you might think, but not so for someone who prints every material on a cold bed with success... What are the official pro statements for a heated bed? 1. Better bed adhesion of course. 2. Less warping of parts. 3. Far less problems with layer seperation. 4. Better print results. And of course there are a few more but not worth listing them. Why do I think most of the four statements are actually unrelated to using a heated bed? Bed adhesion is a matter of print material and surface of the bed / bed preperation, like tape, glue and such. If you filament peels off a cold bed with no adhesion at all it simply means the surface is either unclean or unsuited for the print material. Warping of parts happens because the material shrinks when it cools down, a heated bed is only able to keep a certain height of the print warm. Higher prints won't have any benefit in terms of better layer adhesion with a heated bed. Same goes for seperating layers. Unlike the common believe a heated bed does not fix this problem - it only masks it! Layers seperate because there is not enough bonging between them. This can be due to insuffient extrusion width, too high print layers, wrong print temperature and of course wrong z-axis stepping and wrong extrusion multiplicator. And how good a print comes out of your printer depends on a good calibration and proper print settings - again a heated bed only masks problems ;) Ok, so heated beds are nonsense, right? Well, wrong again ;) They take a lot of worry out of the daily print life to start with. Especially prints with big foot print will benefit, although PLA should never be a problem on a cold bed. If you print long parts in ABS or even Nylon you can have a hard time forcing the plastic to stay on the bed all around the print. A heated bed, with the right settings of course, can make sure your print keeps the shape until it is high enough so the bottom part won't be affected by shrinking anymore. My opinion on how to get the best results... Manage to print on a cold bed first! Smaller parts don't need a heated bed anyway, so use them to improve on your skills of finding the perfect bed material / coating! You will find that once you have really optimised your printer and settings most parts won't need a heated bed anymore. Once you are really happy with the result of smaller prints on a cold bed try something bigger and pay close attention to any problems on the way. For example a big print might start out perfectly but after about 5-10mm of print height you see the part starts to warp and slowly peels of the print bed - especially long parts or thin areas are affected. The infill also affects how a parts reacts during the cooling, so try the same problem print with solid infill as well as only 15% infill to compare - you can stop the print once the problem is identified, don't waste filament. Now comes the magic of the heated bed... You want the temp as low as possible but still high enough to prevent the warping! Why go low if high would help more?? Simply said: If the bed is too hot the part stays soft for a long time, which can badly affect layer bonding and shape. Imagine you squish the plastic on an already "hard" layer - the plastic is pressed flat to be within the set specs. Now if the the layer is still too hot and soft the plastic will push the lower layer in - which of course will expand outwards. So the layer can actually end up to be lower than it should be - layer will still peel ;) Start with around 50° C for ABS and turn the heat down gradually every 10 layers or 25 if you print really thin layers. If the part still prefers to warp go 10 degrees higher. But again: If the stuff would not stick properly on a cold bed work on that first! How do I print on a cold bed and claim it works fine? To be honest, with a lot of time spent on trying, calibrating and finding the right "magic" to put on the glass to make things stick. Nylon, if the part is big, can still be a frustrating task unless cardboard or Bakelite is used but I still prefer the glass bed. I no longer bother with tapes as it can be costly and I hate changing the entire setup just because I use a different material ;) As said, the main key is a proper calibration of hard- and software! If your prints look messy and you spend as much time cleaning your parts as printing them you know what I mean ;) At the moment my "bed magic" is a clear craft glue with methanol as a solvent, mine is from Aldi but similar products can be found in every craft store. The bed is sanded with 600 grid diamond blocks to be as flat as possible and to provide a bigger surface area for the glue. When mostly printing Nylon is first clean the bed with alcohol and put a layer of plastic primer on it before re-applying the glue. With the right temp settings this glue surface can be reused several times with increasing bond to the part. Once the glue start peeling off the bed it cut the area clean and apply another coat just in the spot. A single bottle of craft glue, diluted down by 20%, lasted now about 3 rolls of filament - not too bad for a 2$ investment LOL Seriously though, squeeky clean your glass bed using alcohol and / or acetone and play with different types of craft glue. You want the stuff that is clear and uses either methanol or ethanol as the solvent, don't bother with water based glues! If the glue sticks well to your part but peels off the bed easily try a layer of plastic primer on the bed first - do this outside! However, if your printer is only capable of using PLA anyway you might not want to bother at all and stick to tape ;)

Topic by Downunder35m 


2008 IgNobel Prizes announced!

The IgNobel Prizes are awarded annually for research which "cannot, or should not, be reproduced"; achievements that "first make people laugh, and then make them think". The prizes are meant in good humour, and many winner pay their own way to attend the ceremonies. Past winners have been known to return to ceremonies in later years to show off their achievements to a receptive audience (this year it was a sword-swallowing doctor).The Japanese team that showed slime moulds can solve mazes sang their acceptance speech.The Winners:NUTRITION PRIZE.Massimiliano Zampini of the University of Trento, Italy and Charles Spence of Oxford University, UK, for electronically modifying the sound of a potato chip to make the person chewing the chip believe it to be crisper and fresher than it really is. They also showed that playing the sound of bacon frying can make ice-cream taste bacony.PEACE PRIZE.The Swiss Federal Ethics Committee on Non-Human Biotechnology (ECNH) and the citizens of Switzerland for adopting the legal principle that plants have dignity.ARCHAEOLOGY PRIZE.Astolfo G. Mello Araujo and Jose Carlos Marcelino of Universidade de Sao Paulo, Brazil, for measuring how the course of history, or at least the contents of an archaeological dig site, can be scrambled by the actions of a live armadillo.BIOLOGY PRIZE.Marie-Christine Cadiergues, Christel Joubert, and Michel Franc of Ecole Nationale Veterinaire de Toulouse, France for discovering that the fleas that live on a dog can jump higher than the fleas that live on a cat.MEDICINE PRIZE.Dan Ariely of Duke University, USA, for demonstrating that high-priced fake medicine is more effective than low-priced fake medicine.COGNITIVE SCIENCE PRIZE.Toshiyuki Nakagaki of Hokkaido University, Japan, Hiroyasu Yamada of Nagoya, Japan, Ryo Kobayashi of Hiroshima University, Atsushi Tero of Presto JST, Akio Ishiguro of Tohoku University, and Agota Toth of the University of Szeged, Hungary, for discovering that slime molds can solve puzzles.ECONOMICS PRIZE.Geoffrey Miller, Joshua Tybur and Brent Jordan of the University of New Mexico, USA, for discovering that a professional lap dancer's ovulatory cycle affects her tip earnings.PHYSICS PRIZE.Dorian Raymer of the Ocean Observatories Initiative at Scripps Institution of Oceanography, USA, and Douglas Smith of the University of California, San Diego, USA, for proving mathematically that heaps of string or hair or almost anything else will inevitably tangle themselves up in knots. Their paper has one of the best genuine research titles I have seen for a long time: Spontaneous Knotting of an Agitated String.JOINT CHEMISTRY PRIZE.Sharee A. Umpierre of the University of Puerto Rico, Joseph A. Hill of The Fertility Centers of New England (USA), Deborah J. Anderson of Boston University School of Medicine and Harvard Medical School (USA), for discovering that Coca-Cola is an effective spermicideJOINT CHEMISTRY PRIZE.Chuang-Ye Hong of Taipei Medical University (Taiwan), C.C. Shieh, P. Wu, and B.N. Chiang (all of Taiwan) for discovering that Coca-Cola is not an effective spermicide.LITERATURE PRIZE.David Sims of Cass Business School. London, UK, for his lovingly written study "You Bastard: A Narrative Exploration of the Experience of Indignation within Organizations."Journal of Improbable ResearchThe site will be hosting video of the ceremony in the next few days.

Topic by Kiteman   |  last reply


Very old shielding materials and techniques for permanent magnets and resulting possibilities

Forromagnetic meterials are not just called that for no reason.It comes from ferrous - iron.Iron has the highest permeability at normal temperatures.That means a magnet is attracted to it very strongly.We utilise this for transformer cores, the stuff inside a relay and the moving latch of the relay itself.Like current from an electrical system magnetic fields like to take the easiest route possible.Air is a very bad medium, so any iron close by will be prefered even if it is at a slight distance.You can check with a magnet, a steel bar and some iron shavings - please cover the are with plate first ;)Slightly less known is the option to also guide and extend the magnetic field this way.If you check how far the magnetic field of a magnet reaches and note that distance,then you can add some steel bars or rods at the poles - the field will extend through the metal.The most powerful example of this are the shielded magnets used for hooks or speakers.Except for a tiny area the entire magnetic flux goes through the metal.So in this lefover area the magnetic flux density will my many times greater than what the magnet alone would be able to.What most people don't know is that magnets also interact with other magnets in terms of their fields changing and distorting.The Halbach Array is a good example of this.Seen as a single magnet the array would have one weak and one strong side instead of even strenght for both.Wherever magnetic fields change a conductor can produce electricity or current.This in return causes an electromagnetic field that opposes the one from the magnets.Just drop a magnet through a copper or aluminium pipe ;)Since these distortions are widely unknow to the hobby tinkerer mistakes can happen ;)In the early days of exploring science some people already knew about shielding.And they also knew that certain metals have certain properties.Where it is quite hard to create a good coil from steel wire, copper works fine as it is not magnetic.What would then a copper shielding do?If you have two moving magnets with only a tiny gap then the resulting field distortions are quite huge.A copper shield around the magnet like a pipe would then react to these changes and also create a megnetic field that works in relation to the enclosed magnet.In simple terms it means the shield would let the magnet appear weaker or stronger depending on the field change.A quite old document I found gave some hints on how people thought in different directions back then.It was in regards to the design of a magnet motor by the way.Here various magnets were shielded in tube made of a copper-bismuth-alumium alloy.These tubes were then electrically connected so it created a single loop conductor.The claim was that the resulting electromagnetic field of this ring would drive the fields of the enclosed magnets sideways out of alignment.Like bending straight pastic tubes sideways.This "pulsating" would always happen when the magnetic binding forces reach max and so basically drastically weaken this binding effect.Another document talks about a "magnetised brass rod".A holes of the rod diameter is drilled through a block magnet.Not from north to south but through the middle where the flux is greatest.The claim here was that if that rod rotates fast enough a very low voltage with a very high current will be generated.Sounds easy and interesting enough that I might have to test one myself one day.The best one however is what I consider a hoax or being as good as Starlite.Someone back in 1908 claimed to have created a material the reflects magnetic fields.In lame man's terms it would be like an insulator around some electrical wire.The claim and some pics showed it, was that no magnetic field can pass the material.Or to be correct only a tiny fraction of what would be possible through air.A small magnet inside a longer tube of this material would create almost the same attraction to steel at the tubes ends as on the magnet itself.Measurements showed the field strength would be almost equal to a long mangnet of the same field strength.Imagine guiding the field of a big and powerful magnet through a tube around some corners or other magnets and then end in just a tiny hole for the entire flux...Too bad he never shared his secret formula to anyone knows to mankind.Isolation...Imagine you have an array of changing magnetic fields and quite strong magnets.Then you might face the problem that your focus on the "working" end neglected the other end of the magnet (stack).Providing some iron core material will keep thes field lines contained and away from interfering with your setup ;)But it also allows to use te otherwise unused end of your magnets more directly.For example by guiding to another magnet to affect its field strenght ;)Placing a sheet or steel between two magnets in a setup provides a "shared pole" so to say.If you have a north and south pole on a rotor at a distance of 5mm then a sheet of steel between will drastically weaken the strenght and reach of this combined field.It is like pulling the arch between the magnets down to make it more flat.And at and an angle the resulting field will also be slightly angled ;)Capping...When I first encounter this many years ago I couldn't really make sense of it.Quite complex..If you check the magnetic field lines with iron filings or similar then you notice how they go in a rounded manner from pole to pole.This is because the single field lines are of equal polarity and will dirve apart like opposing magnets.By capping the ends of a magnet you provide a short.Instead of diverting out like mad they will follow the cap and create very intersting magnetic field in return.If both poles are capped it is like pressing the magnet flat but without having a field on top of the oles - only aorund the center part.For this the thickness much must match what is required for the flux density.As a rule of thumb: if the end is still very magnetic then it is not enough material tickness ;)Interacting fields in a tube...This one is quite old too and seemed to have found no usable inventions apart from simple magnetic spring replacement systems.But it gave me some clues about Tesla "earthquake machine" ;)If you place a magnet in a tube and at it's ends magnets with opposing fields to the one inside then you can fix this magnet in place.Push one magnet deeper and the distance from the inner magnet to the other end will shrink the same amount.In this old paper two coils were around the pipe with the inner magnet between them.In this gap and at about the same width as the magnets length another coil was placed.Violent shaking would then create electrical energy at much higher level then modern shaker torches.In return an AC current on the outer coils would cause the inner magnet to move back and forth to create electricity in the center coil.According to the paper possible uses include: core less transformer, measuring minute changes in AC voltages, providing free power from a running motor...The last one had me stumbled for a very long time.Until I considered a different configuration.The whole thing is basically a linear DC motor - with correct timing of course.And in some motors we use permanent magnets.I am starting to wonder what would happen if we would design a rotor magnet like this?The running motor would be subject to constant field changes that affect the rotor.And a normal motor is always "even".By using four magnets instead of one we can push the field really flat.This means the area where the coil would operate (about 1/5 of the magnets area) will have a much stronger field.The resulting torque should be higher by about 25% !!Even a simple two coil model setup should show a significant increase in performance here.Timing is critical here but I tried some calculations based on 8 poles and the required "on times" for the coils.In a standard motor configuration with a single rotor magnet the coil is active for about 12° of the rotation.With a 4 magnet configuration this "on time" can be reduced to under 8° of the rotation to get the same amount of torque.An energy reduction of about 4% if you neglect losses and only think in time.If you think in terms like impulse energy then we are talking of about 15% !Shorter on time but still much higher flux density overall than for the long standard timings.Going the long run now:If you check how most DC motors work then you realise soon that for most one rule seems to followed.Only use one coild pair at a time.This is quite contradictive if you consider the geometry and options.A dual commutator would allow to use a second coil pair with a field OPPOSING the magnets instead of being attracted to it.After all: on you bike you pedal with both legs and not just one...And if you do it professionally then yu do the same as I suggested for the motor - you use the up pull of your legs as well.Doing it brushless only requires amodified h-bridge desing to drive the second coil pair at the right timing.Some will now say that it requires twice the energy, I say that for the same motor size your get twice the torque!Just imagine what that means in possible weight reduction for a motor - or its size to deliver the same torque at the same power levels when a normal motor is used ;)The more poles the more complicate the precise timing but no big deal really with modern electronics.Can it be improved even further?I though long and hard about that one until I considered EMF.A DC motor produces a lot of it when the elecromagnetic field collapses in the the coils.We do not utilise this energy...There is a tiny delay until the released energy levels are at max.My theory is that it should be possible to divert this energy into another coil set.If that coil is not the next active but still within a strong enough field area then the EMF would actually add to the drive of the motor.Only downside is that according to my calculations at least 16 poles would be required to get an optimum result.Way above of what I can create in my little garage :(In theory it should then be possible to reach about 98% efficiency for the motor....

Topic by Downunder35m   |  last reply


Solar - PV versus Solar Oven with Peltier

I was browsing the site as I am often wont to do, and spent quite some time revisiting old 'ibles covering various solar projects, almost all of which are heat related. I understand from general consensus that PV (photo voltaic) solar systems are very inefficient and one of the worst ways to harvest solar energy (when considering the cost of construction and the energy transfer capacity, etc.) Almost everyone who knows what they are doing suggest that the best (and easiest) way to harvest solar energy is to collect the heat - be it to heat air or water, cook food, or other such purposes.Now, I have recently been fascinated by a discovery relatively new to me, peltier units. These devices, for those who don't know, can work in one of three ways. They can harvest and/or produce either heat, cold, or electricity.Basically, if an electric current is run through a unit, it produces heat on one side and an equal amount of 'cold' on the other. Yes I know you can't produce cold - but for the layman, that is what we call it.Or, if one side is heated while the other side is cooled, the unit produces an amount of electricity from the difference in temperatures. One example I have seen and plan to make use of is in vehicles - if you place one or more of these on your exhaust manifold, or any other location where the engine produces waste heat, and airflow can reach it to cool the other side, you generate electricity from the waste heat energy that would otherwise just be . . . well, wasted.But it occurred to me today, if you had a unit attached in the middle of a solar collector, focusing sunlight on one side of the peltier unit, and isolate the other side of the unit in some cooling medium (perhaps even just air with a heat sink of some sort - more likely a cooling liquid though), how effective would this be at harvesting solar energy (heat) into electricity?Actually, I have been using the more common name of peltier, but I believe that for this application a seebeck unit (which is nearly the same, but different) would be required. As I understand it, Peltier units are used more as coolers and are almost always constructed with Bismuth Telluride (Bi2Te3) and used around room temperature and below; while Seebeck units are good for power generators are often constructed of PbTe or, SiGe as well as Bi2Te3 and are used at much higher temperatures.From http://en.wikipedia.org/wiki/Thermoelectric_effect :The effect is that a voltage, the thermoelectric EMF, is created in the presence of a temperature difference between two different metals or semiconductors. This causes a continuous current to flow in the conductors if they form a complete loop. The voltage created is of the order of several microvolts per degree difference.((more info can be found at the referenced wiki page on formulae etc.))Just curious on if this would ever be a decent way to harvest solar energy into electricity. I have also thought up using a thermal siphon solar heating system in which the liquid flows past one or more water wheels which power a small (and obviously slow) generator - but at that point I believe it would be so inefficient and limited in use as to just have absolutely no practical application. The peltier unit (used as a seebeck unit) would probably do better, but I am not certain, which is why I post the question.

Topic by karossii   |  last reply


Did you see a UFO or not?

I could not sleep so I went for a little bike ride to get some fresh air and burn unwanted kalories. To my surprise one really bright "star" began to move and because it was night my conclusion was a plane at low altitude or making a turn. After a while however it looked more like this "light" is still coming towards me and if you know planes this would mean it should have crashed already - which it did not. But it definately came closer and once almost over me I also realise it does not move in a straight line, more in a slight zick-zack movement. Biggest surprise was the shape I could make out, definately no plane that I know of! To me it looked like a cigar shape which was much wider in diameter on one end. Can't say front or back as the flight patter did not incate anything like this. Any directional changes happened without the shape changing direction, if it moved to the right than without turning - it just "slided" while the long shape kept pointing in the same direction as before. Took about 10 pics on my phone but even after checking on the computer there is only black on a black background, not even a single star visible :( Just to get me right here - I do believe in other planets out there having intelligent live but I do not think intelligent "creatures" from outer space would come to visit us. The term UFO means unidentified flying object and nothing else was there that I saw - just something that makes no sense in terms of following known laws of physics flying through the night sky. Would not even bother to write about it if any of what I saw would make sense to me. There was no sound, which was really strange. IMHO the craft was at an altitude between 1000 and 3000m not higher. It also seemed the light I thought came from a plane was coming directly from the fuselage or hull and not a lamp, looked like the outer surface was glowing. But seeing something moving quite fast over your head with no sound at all is just weird.... The zick zack movement was strange too but when the craft took off to disappear into the night it was like instand accelleration. Within an instand the light went really bright and was gone over the horizon - never seen anything move that fast! I know there are lots of secret military aircrafts out there, same for people playing with drones but this was much bigger, would say at least 400m long. Even if the altitude would have been much lower in reality than what I thought it would have been huge - and totally silent. Spent the last hour or so checking some videos on Youtube but nothing really matched what I saw. So my question(s): Did you ever see something moving with impossible speeds, making impossible turns or accelerating like no tomorrow in the sky? And if so: Did it look like an oversized cigar, bigger on one end and with a "glowing body"? Do you know of any prototype craft being the size of at least two Airbusses in lenght that can fly without making any noise at all? Disclaimer: I do realise what sort of "crap" I am writing here. I also acknowledge that I don't know everything that can fly. I do not think that I saw an UFO in terms of being "out of this world". Yes, I know my level of insanity ;) I do not claim to have seen or being abducted by aliens either ;) And no, I have neither been blind drunk nor on drugs when I saw this ;)

Topic by Downunder35m   |  last reply


A little magnet experiment for everyone!

Some people just love to play with magnets and have a lot of them.If you are just like that and like to tinker a bit then I might have something for you.What magnets you use for the following experiment does not really matter but you should have 20 or 30 of identical properties.Can be disk magnets, block magnets or cubes, just not spheres ;)If you have a 3D printer you use it to make it fancy but a peice of wood, acrylic or such and a drill will do for round magnets.For cubes or flat packs you can make retaining walls on a flat surface.The experiment goes like this:I assume you already tried ways to combine your magnets to make them stronger, like stacking them up.But there is another way to really increase how strong they are combined.Start with one magnet at the center.Then like a ring add more magnets around it but with the oppisite side up.The created mounting solution is to prevent them flipping up and together, you want them as close as possible though.Add another ring and change the direction of the field again.Try this magnet, once all magnets are secured and compare the holding strenght to any other combo you tried so far.It will be much higher for the same amount of magnets.If you want to prevent the use of glue then try to create your mounting system with a really flat but strong enough bottom - this will then be the contact surface.Slightly reduced strength but you can re-use magnet with ease.But if you want to get a really strong one you need cube magnets.Like before you want to create some sort of grid, this time we go for a square.Start with cube in the center, facing north up.Leave enough space in your construction to add 8 more cubes around it - like on the face of a rubik's cube.Leave them empty for now !Add nother row, this time 16 to keep the square.Of course these one go with the south side facing up!Again one empty of 48 and then one last one with north side up with 196 magnets.Ok, to be fair, you wouldn't be able to pull it off a metal surface unless you used really tiny cubes, so if in doubt then go for just to 48 and leave the enter one out for now.Should be quite intense but similar to what any other shaped magnet would have done.Time to fill the voids!Add the cubes in the spce between the magnets so the north and south side face the magnets next to it!So basically sideways but in the correct orientation.You can then also add the center piece - try either orientation for that one ;)What happened now is that you forced the magnetic field lines to go up instead od for trying to go the easiest and shortest way to the next magnet.And "up" is where our magnetic surface would be, which provides the now overdue shortcut for the magnetic fields.Be amased how much stronger this version is and how much even 3x3x3 cubes would accomplish.With 10x10x10mm N52 magnets you might be able to use them support our wieght if you pull straight dwon from a horizontal surface...Ok, kidding, not just might, unless you are really big...One 10x10x10 might hold about 6kg.Stacked up a bit more but having 20 or stcked up would not be much stronger than 10.Even just 25 magnets with one in the center, one row of sideways orientated and one row with opposing field to the center one would be hard to remove from a steel surface.If we go with the imagined 6kg per magnet we could assume to get 25 x 6 = 150kg of holding power.Check you single magnet first then compare to the square of 25 ;)Consider using some plastic between magnet and surface so you can at least slide or pry it off if you have to.You can also combine magnets or a new one that has one side appear much stronger than the other.Meaning that for example on the north side it could hold 20kg while on the south side only 5.

Topic by Downunder35m 


The "truth" about climate change - a little story

Global warming, climate change, jelly fish attacks, changed ocean currents...We all know the highlights from the news but what is the real deal behind all of this?It can't be denied that burning fossil fuels with no regrets has an impact on our globe.CO2 and other gasses or elements have been trapped for thausands of years.We release them all into our atmosphere and while doing so keep adding more harmful stuff.So, of course it is easy to say that if we would have nver used our fossile fuels to this extent then our world would be unharmed and a happy place throughout.Even if we would ignore the impossible task of making it where we are right now without having used any fossile fuels: How much would it be different?If we trust the offical climate data that has been collected then it clearly shows a rise in so called climate changing emissions since our industrial revolution started.Be it data from the ice, core drillings or just sample taken from old canyons - the results are all the same.Since the late 1800's there is a steady rise in emissions, CO2 and all the other things we don't really want in our air.And for good reasons all these green advocates try their best to stop us from doing more harm.Since the 80's we started to actually care more, better engines, catalytic converters, cleaning mechanisms for our industiral waste and chimneys.But did it make any change or difference?About 40 years now some countries try hard to do it right, so this must show up somewhere?!Well it does not.You see countries like the US never really cared about climate or the enviroment if there was a cheaper and easier option.Just check how long it took them to even acknowledge that our climate is changing due to our interference...Then there is China and as we have seen with the olympics they literally have to shut down production so you can see for more than a few km...But the same is true for so many other countries.Like everwhere else the industrial revolutions comes sooner or later and as always the cheapest way is done first and for far too long.And with the delay in reactions and consequences it is now certain that the worst is yet to come.Of course there is also another side to the entire story - nature itself.We destroy it where we can to safisfy our need for being cheap.Ever wondered where all this cheap furniture is coming from?Or all the wood used throughout the world?Rainforests are disappearing, flora and fauna is destroyed.In most cases with a lot of fires as it is still the easiest way to clean up when done.Now add the vulcanic eruptions that increased over the past 20 odd years around the world.And if you dare all the bushfires or natural causes.Combined this causes a higher impact than all our burning of fossile fuels - and it adds to the mix.And this brings us back in time.Taking the records of climete conditions all the way back to before the dinosaurs showed us that we had periods of much higher temperatures than what we might see soon.CO2 level at some periods were so high that the earth literally was a green house.So why did we humans amke it anyway onto this earth if chance were so bad?Species adjust, evolve or go extinct, new ones appear...Well, unless you are a croc or so and really don't care about Darvin and evolution ;)Does that mean we are on the way to become a new species?Sadly no, because we are the cause of all our problems.We now use technology and science to adjust nature and the enviroment to our needs.It gets too hot? Well add an airconditioner, will you!?The ground water is too contaminted to drink? Well, why do you think we invented bottled water?!You need room for new homes? Don't mind the flood planes, just drain them and build, there was no flood in over 30 years...See, even if we would go fully green and honur nature around the world from today on.Even if we try to clean up the mess we already created.The effects of what we did over the last 40 or more years are still in progress and far from over.Like a good stew it keep cooking until it is ready to serve.But strenght comes in numbers!Like a virus we keep multiplying even in areas with very limited ressources.After all, we just import what we need..Natural selection is being eliminated so pharma companies can make a living too.From just over 40 years our "natural" life expectency increased now to well into the 80's.You are not fertile? No problem we have means to fertilise your eggs with the sperm from hubby!Already suffering badly from diabetes, asthma or other chronical illness? No problem, have some kids anyway.And just to top it always make sure to avoid natural foods in favour for processed and artificial ingredients.In nature the weak, the sick, the old, the malformed and incapable are a food source.We took this food source away, keet them around, care for them and make sure really everyone has the same chance in life.In life - but not in nature anymore!Social evolution meant that natural selection was no longer a requirement to ensure a strong "tribe" or hunting party.We compensated the drain on ressources and all pharma companies are still very grateful for this.No this is no weird rant on humanity or the idea of some mad person, it is just the naked reality we like to ignore.A horse breeder will not accept a weak and constanlty sick horse for his breeding stock.A broken leg, like for a cow usually just means the animal is put down.Some dog breeders still prefer to cull a few pups just because the color pattern is not nice enough or the ears are too short.Even if you just breed fish you o through all sorts of troubles to ensure you have the best genes available in your tanks.You think this is already going to far with the ideas, I know :(But we have real world examples highlighting the results of the exact opposite: Inbreeding and ignoring the defects in genes and health.The british royal family destroyed the italian and russin monarchies the same was the spanish and protugise, even impacted on the french.In times when there was no clue about genetic defects or deseases that can be dormant in females but very active in males, the british royalty simply kept providing tainted bloodlines to the other royal familes.No offsprings that are male and of good health meant the end of their monarchies.The british survived by allowing the common folk to join the blue blood lines and now it is common in all the monachrchies left in the world.Remove the carries, provide fresh genes to get a better diversity.Really no offence, but just look at Charles and Camilla ;)Jokes aside: the story of the european monarchies shows what happens if things go too wrong.From hunters a gatherers that either kept healthy or died out we eveloved to having a gene pool that is full of nasty surprises.Again no offence meant in any way or to any person!If we compare our world with a big aquarium than it might have eveloved like this:Once there was a bowl full of plants, guppies and lots of other fish and creatures living on each other.Over time the guppies learnt when the feeding times are and made sure they get most of the food.Slowly the other psecies had not enough room and food anymore, only the hunter had a good linving with the huge supply of guppies.Then the guppies managed to reduce the dangers from all predators around and started to really take off.Soon every guppy had only conerns about having a good life and enough food.The waste got more and more, the sick and ill too.The last hunter able to fight them died off as he too suffered from the wasten the changed enviroment and gnetic defects transfered.Now there is little plants left, guppies everywhere, crap everywhere and even those guppies only living a few months still manages to find a partner to ensure their tainted gene pool spreads into the general population.We have no tank owner getting the balance right again, removing the sick and weak, we humans just keep going strong and if the crap pile gets too high we put grass and houses on top of it....We humans don't like to be compared with fish, a virus or any other lower being for that matter.These hings just don't affect or concern us.And anyone who dares to do so anyway has a long list of nasty words thrown at them.Is it because we humans can't tolerate the truth?Or is because deep inside we all know but refuse to think about it?

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