I am stuck in my research,please tell me a way to make a linear electromagnetic field,other than making an outer core for it please help me
Posted by ajose4 4 years ago | last reply 4 years ago
Hey everyone. I have a question about a linear actuator that I'm putting on my sawmill to control the throttle. On a sawmill you either need to be full throttle or idle. I've already got the actuator mounted and it works great. Now I need a controller for it. I've got a keyless remote from a auto parts store that I would like to use. I also would like to have a hard wired button. The kicker is that I would like to be able to push a button on the remote or the wired button and the actuator go all the way out. And then push the same button and it come all the way in. The actuator has built in limit switches so it will stop on its on either all the way out or in. This may not be feasible for me to do but I was just thinking by using relays it may be. If I can't use just the one button then I'll have to use two. There should be no need for a stop button since the actuator has a limit switch at both ends. Thanks
Asked by papermaker007 7 years ago | last reply 7 years ago
I acquired this mechanism which I would like to modify for ease of use. The original set up uses a linear actuator and a 3 way toggle switch. The linear actuator comes with built in limit switches. The 3-way toggle is not practical as my hands are fully utilised on the work bench. I would like to modify the set-up so that I can use a single foot pedal switch to get this motion. One step on the foot switch and the linear actuator extends to its maximum length. Then another step on the same foot switch and the linear actuator retracts to its maximum. Any help with the circuitry and parts will be greatly appreciated. Thanks in advance. ROY
Asked by anslemroy 3 years ago | last reply 3 years ago
I know how to do servos and such, but the actuator has 5 wires, and i dont know where to put it.
Asked by therobotman 6 years ago | last reply 6 years ago
The question says it all, really. I built up a linear power supply shown below. My unregulated 12V supply can fall as low as 14.7V @ ~ 2-3 A but if I end up being unable to go higher than 9.5V at 3A. Because I'm driving a motor as a load, the current drawn is very dirty. At 10V I see small dips that correlate to dips in the supply voltage when it goes just under 15V. So what can I do to help alleviate this, as I was under the impression that I would see a absolute maximum of 3V of dropout, not a whopping 5V. (p.s. the maximum gate current into the S8050 is 10mA, but currently set to 6.77mA w/ a 10 ohm resistor) p.p.s: MY design uses an LM324, which is really not the best, as it's slow and cannot sink much current. To alleviate the first issue I simply added current mirrors to aid the op amp in sinking current in a simalar fashion as a current source used for an open collector outputs. What op amp should I use instead for better performance? I suspect the LM324 due to it's low slew rate and low GBP may cause poor high frequency rejection (esp. if I choose to use a switching pre-reg) and poor high frequency load regulation (causes poor transient response on the output) Op amps I can choose from: LM324; // slow, from my testing, this one has inputs that work to ground :D LM224; // ditto, but in a weird package LM386; // slow, but from my testing, this one also has inputs that work to ground. LM741; // ancient relics of the past, not rail to rail by any means, sucks IMO. UA1458TC // ancient relics of the past, I don't have much knowledge of them. Inputs do not work to ground. LM318H; // its in a fancy metal case :D TL072CP; // JFET inputs, but I think the output current is limited and the output can't go below the noninverting input. TL2072AC; OP37; // These things can't even give a stable output by themselves! OP27; // ditto LT1007; // have not messed with it much LT1167; LT1191; LT1363; CRAZY fast, 1000V/uS!!! Maybe too fast... LT1360; LT1112;
Asked by -max- 2 years ago | last reply 2 years ago
Hey, I have a robotic project that I have a deadline for. i have everything in place, but i cant think of how to connect the linear actuator up to my Vex Cortex Microcontroller. it has 5 wires, but I cant fit them in any of the outlets. Sincerely, I cant give my name out
Posted by therobotman 6 years ago | last reply 6 years ago
I have a 73 Bronco, I am trying to install a set of step bars onto. I would like to have them mounted on a linear actuator. Is it possible to have them wired to a door jam switch, so they would lower when door is opened, and raise when closed? Every switch I have seen is a toggle, which won't work for my application. Any help would be greatly appreciated! Greg
Asked by greg dill 6 years ago | last reply 6 years ago
Basically, I need a dial that would command this linear actuator https://www.servocity.com/sda24-263 to advance in one inch increments on either a dial or a touchpad or a slider. EvanBrenner@gmail.com or 917 414 5472 Thanks! Evan
Posted by EvanB65 1 year ago | last reply 1 year ago
Hi, I'm not sure if it's appropriate to post this inquiry on instructables but I thought I'd give it a try. Basically, I need a dial that would command this linear actuator https://www.servocity.com/sda24-263 to advance in one inch increments on either a dial or a touchpad or a slider. I'm not an engineer and I don't really have time to build this myself - would anyone be interested in doing this for a fee? If it would help in assessing the project, I now this controller would work https://www.servocity.com/digital-manual-speed-controller However, I need the dial or touch pad to allow for discrete steps and not be sort of vague. Any help would be much appreciated. I'm just not sure where else to turn. Thanks, Evan
Posted by EvanB65 1 year ago
Hello everyone. I'm trying to run a linear actuator with built in limit switches by remote control. I bought the remote from a parts store. The remote was supposed to be used for windows up and down, door locks and other stuff. I would like to be able to use the relays that I already have on hand. I want to be able to push a button on the remote and the actuator go all the way out or in without holding the button down the whole time. Thank for your help.
Posted by papermaker007 7 years ago | last reply 7 years ago
I need a simple, not powerfull, linear engine. It has to move just like an inch back and forth, chaning directions on its own when it reached the end of his stroke. Even 5mm would be enough movement. I think about of something based on a neodymium magnet in cylinder shape. It has to be as simple as possible, i don't need any control for frequenzi, because if it works.. i can work out more from there on my own. Only thing important, it has to be small, like the lenght of a half pencil and 2cm in diameter would be ok (for the moving part, electronics placed elsewhere don't matter). A normal rotating engine with a shaft doesn't work for the design i have in mind :(
Asked by wupme 9 years ago | last reply 9 years ago
Hi. It's about how are organized threads into forums. Currently forum threads are forked : you can reply to a comment separately, and each of your reply will make a new fork if somebody reply to your new comment ... this makes threads like trees ... Personally, I don't find this system very handy, more particularly when the same thing is being actively discussed in several forks. This system is good for short chats and when commenting instructables, but when it's about debating, it quickly becomes confusing ... For the forums, I'd prefer a system with a linear thread where messages are ordered according to time, and where we have to quote the persons we want to reply to. Several discussion could get "multiplexed" on the same thread, but personally, I find that less confusing as long as there are quotes. What's your preference ?
Posted by chooseausername 11 years ago | last reply 4 months ago
So, my friend and I are building a Coil Gun! Nothing super powerful, but it will punch a nice hole in a cardboard box. Here's the problem; we want to add an ammo counter to it. We were thinking of using an IR LED, a Photo-transistor, and a voltage comparator circuit, kind of like the one here (http://home.cogeco.ca/~rpaisley4/PhotoDetectors.html , first photo, right circuit)) . The circuit would send a pulse when the projectile interrupted the IR beam. Now what? The magazine holds 6 rounds, so maybe 3 green LEDs, 2 yellows and 1 red to count the ammo. We were thinking of maybe using a 4017 counter IC to advance down an LED after each pulse, but doing it this way means only one LED is lit at a time. We would really like it if somehow we could have all the LEDs lit, and after each pulse one would turn off, but I'm unaware of how to do this. Oh yea, we don't have access to a micro-controller, which is why we have this problem. So to recap, we need a circuit that will light 6 LEDs when powered on, then shut off one LED for each pulse received. Is there any way to make a circuit that does this?
Asked by aeronut01 5 years ago | last reply 5 years ago
Arduino comes with a simple program to make an LED fade on or off, however, as far as I can tell, the apparent brightness of the LED does not change linearly with the wpm duty cycle. After some research I found that this is because humans percieve brightness logarithmicly, not linearly. (Also, LEDs don't change brightness linearly with current, but sisnce I'm using PWM, i don't think that comes in to effect.) I found a simple look-up table to correct for this on this page. 255, 180, 128, 90, 64, 45, 32, 23, 16, 12, 8, 6, 4, 3, 2, 1,0 This seems to work very well, but I don't know where this comes from. Does anyong know the ectual equation to get the % duty cycle from the %brightness? I like to abstractise things.
Posted by Vick Jr 8 years ago | last reply 6 years ago
Zener diodes only regulate voltage when it is within its regulation range. in a simple zener regulator, voltage in the resistive load changes as the resistance of the load changes, but this is usually a small change. now, my question is, is it possible to prevent this small change? how?
Asked by codestroy7 7 years ago | last reply 7 years ago
Have two old electric linear screw actuators that work great. I Need a lift table but can't figure out how to put it all together. I don't know what width or type of metal use for the lift or the bolt hinges???. Does it have to be a scissor lift or can I keep the actuators where they are at each end of the bed, wire them to work together and make a lift that way? I need an affordable way of doing this and it only needs to lift to about 500 lbs. from 17 inches off floor to 30 inches off floor. All framing is angle iron but seems heavy duty. Anyone's help if greatly appreciated as I just cannot afford to spend $ 1000. + on an electric massage lift table. The pic is after everything but the motor/actuators were removed. Thanks Deb
Posted by DebMaudie 3 years ago | last reply 3 years ago
Several questions: -Calculate the force of a linear induction motor from the magnetic field/current (aluminum induced surface)? -How does one determine the direction in which is moves considering the magnetic fields are not static and there isn't a second magnet since it is just an aluminum induction surface? -Is there an optimal current frequency for a linear induction motor? -Is there any way to make a single phase Linear induction motor, and avoid using 3 phase current?
Asked by amelius 6 years ago | last reply 6 years ago
I'm thinking about making an alarm clock that literally gets me out of bed! The alarm clock would start tilting the bed to one side, untill i either get out of bed, or fall out of bed :) I was thinking of using linear actuators on one side of the bed to do the tilting. Does anyone here have any experience with linear actuators? How strong are they, and where can I buy them cheaply? Any other ideas on how to tilt a bed? Cheers - Chr
Posted by chr 11 years ago | last reply 11 years ago
I am trying to wiring two limit switches onto a linear actuator. One to stop the extend stroke but will allow you to retract the actuator. The other limit switch will stop the retract stroke but allow you to extend the actuator. The actuator is installed on a door I need it to stop on the extend stroke and the retract stroke so it doesn't damage anything. I have an LACT8-500A actuator and the company doesn't make a limit kit for the adctuator.
Posted by youaintwrong 8 years ago | last reply 8 years ago
Im trying to build a circuit in which an input uses linear motion to control a rotating servo. the servo rotates clockwise/counterclockwise, and the input should have 3 inputs. turning the servo clockwise, turning the servo counterclockwise, and a neutral option so the servo doesn't have to always move; the neutral would be between the to rotation inputs. The closest form of an input I've found so far is a sliding potentiometer since it is controlled by linear motion. If there's a better input that can have those 3 inputs i'd love to know.
Asked by explosive_bagels 7 years ago | last reply 7 years ago
This was originally going to be a question on mechanical advantage and tinsnips but I've realised the answer during typing the question. So, my follow-up question is . . . I'm looking to extend the throw of a servo and convert this to a roughly linear motion but still keep the whole mechanism compact. I'd like around a 4 to1 gearing (with corresponding loss of force, of course). Is there a simple linkage I should be looking at to get this?
Asked by AndyGadget 7 years ago | last reply 7 years ago
Hi guys, I have a dmx controller which is connected to two sunstrip lights which I control with my foot during gigs. It means I have to balance on one foot and slide the fader up and down with the other in order to get a swell/strobe effect. Have you any idea how I could hack it to turn the horizontal linear motion of the fader into a vertical motion (basically a pedal I can stamp on it swell like a wah) Any suggestions helpful. Cheers!
Asked by DaveP177 15 days ago | last reply 9 days ago
Hack your Servo V1.00: Make a powerful linear actuator using a standard hobby Servo Provided you have the tools and the servo you can built this for under a couple of bucks. The actuator extends with a rate of about 50mm/min. It is rather slow but very powerful. Watch my video at the end of the post where the small actuator lifts 10kg vertically. Materials List Tools list - hobby servo - standard hobby brass tubing -OD: 4.0mm, ID: 3.4mm -OD: 5.8mm, ID: 4.5mm - standard hobby styrene tubing -OD: 4.8mm, ID: 3.5mm - M4 studding - 2 x M5 washers - 2 x M4 nuts - 5 minute epoxy - cyanoacrylate - grease - multi-strand cables - heat-shrink tubing - standard tools – screwdrivers, scalpel, files etc. - dremmel multi-tool with ceramic abrasive disk, or similar - hand-drill + 4.9mm + 2.5mm drill-bits - M3 tap - M4 tap - soldering iron - glue gun - small vice - small saw - sanding paper (relatively fine) - small flame torch http://www.01mech.com/sites/default/files/images/material_tools.jpg Procedure - I will be giving instructions based on the dimensional parameters of the Hitec HS-300. The procedure remains the same for any type servo. I strongly recommend you read the whole post before you start. So lets make a start, shall we? - Open your hobby servo, remove control electronics, feedback potentiometer and mechanical stop on the servo’s output gear. - Solder new cables on the servo motor’s leads. - Drill two 4.9mm holes on the servo case bottom cover. These should be located longitudinally along the centre line and 9.5 mm from each end (this applies on the Hitec HS-300 and is also true for many standard servos but depending on your servo type there might be differences). The M4 thread will come out from the servo body using one of these two so this hole must be located directly below the centre of rotation of the servo’s output gear. Be very careful since this alignment is very important! If you don’t get it right you might have to use a new servo! The more accurate you are, the longer your servo will endure. http://www.01mech.com/sites/default/files/images/bottomCover_potHead.jpg - Measure the dimensions of the rotating shaft of the potentiometer on the servo’s original electronics – note the geometry in general. The shaft should be flattened right at the tip in order to prevent it from freely-rotating once inserted into the servo’s output gear. - Take the M4 studding (M4 thread) pick one end and by using the dremmel and the abrasive wheel tool, replicate the tip of the servo’s potentiometer on that end. Start by decreasing the diameter of the thread, rotating it steadily by hand against the abrasive disk (normally to 3.5mm in diameter and at least 6mm in length). Try to think of your fingers as the chuck of a slow-turning lathe. Once the diameter of the thread is down to the pot’s shaft diameter, flatten the tip according to the potentiometer’s tip. The idea is that the thread must be inserted in the servo’s output gear in the same way the potentiometer did before. The better the fit the longer your servo will endure. http://www.01mech.com/sites/default/files/images/thread_modofication.jpg - On the flat tip of the M4 thread, screw the two M4 nuts approximately 20mm down its length. Following that, insert the two M5 washers. - Insert the thread inside the servo and adjust the distance of the nuts and washers down the thread such that the servo case bottom cover closes properly and the motor rotates efficiently. Basically, you have to make sure that once the thread and the servo are assembled there is no pressure between the servo case bottom cover and the nut-washer assembly. Similarly, you have to make sure that once the thread and the servo are assembled there is no gap between the servo case bottom cover and the nut-washer assembly. Once again, the better the fit the more your linear actuator will endure. - Once you find the optimum position carefully disassemble the servo, remove the washers from the thread and use a drop of cyanoacrylate on the side of the nut that was in contact with the washers in the assembly. Let the glue to settle for 5 minutes. Unscrew the second nut by 10mm towards the flat end of the thread, and prepare a small epoxy mix. - Put the mix between the two nuts and screw the second nut back in place. Once in place also use some epoxy on the back of the second nut as well. Ideally you should sand all contacting areas before you apply the epoxy glue. Leave to settle for at least 6 hours (even if you use a 5 min epoxy). http://www.01mech.com/sites/default/files/images/copper_thread.jpg - Secure tightly the 4mm diameter brass tube onto a vice by flattening the mounting end and use the M4 tap VERY carefully tapping as deep as possible (at least 15mm). Using the dremmel cut 10mm out of the threaded part of the tube and then verify that the created thread runs along the whole length of the small threaded tube by screwing it onto an M4 screw. Keep the 4mm threaded tube on the screw for handling purposes. Apply a layer of solder on the outside surface. http://www.01mech.com/sites/default/files/images/thread_solder.jpg - Take the 5.8mm diameter brass tube pick one end and try to sand at least 5mm into the tube (on the inside). Mount the brass tubing on the vice without squishing it and apply a thin layer of solder on the inside. - Ignite the flame torch, take the 4mm threaded tube (holding it by the screw) and move it on the soldered end of the 5.8mm diameter brass tube which should still be mounted on the vice. Using the flame torch heat-up both tubes and carefully insert the 4mm threaded tubing inside the 5.8mm tubing until is fully inside. Use a pair of pliers and insert the brass tube by holding the end of the screw that sticks out. Hold the threaded tube levelled inside the 5.8mm tube until the solder settles. If you do not have a flame torch use a candle, your soldering iron and your patience :). Remove the screw. The end result will be the cylinder of your linear actuator. http://www.01mech.com/sites/default/files/images/thread_cylinder.jpg - The cylinder length should be equal to: the actuator’s desired working length (stroke) + length of the 4mm threaded tube which is inside the 5.8mm tube + 10mm for the mounting hinge at the cylinder end. - The thread length should be: the actuator’s desired working length (stroke) + length of threaded tube which is inside the 5.8mm tube + length of the thread which resides inside the servo casing, which is model-dependant. - Take the non-threaded/non-soldered side of the cylinder and drill a 2.5mm hole through, 5mm from the tip. http://www.01mech.com/sites/default/files/images/cylinder_heatShrink.jpg - Cover the entire length of the cylinder with heat-shrinking tube and cut-off any excess bits. The 2.5mm through holes made earlier on the non-threaded side of the cylinder are now covered. Use the drill again to expose them and tap them through, using the M3 tap. Screw a 20mm long M3 studding or simply cut-off the head of a 20mm long M3 screw. This will act as your cylinder mounting hinge. - Take the 4.8mm styrene tubing and M4 tap it 10mm deep. Cut a small ring 5mm in length and screw it in the M4 thread fully, from the side of the nut that was in contact with the washers (long side of the M4 thread). This will act as bushing between the thread and the servo’s case bottom cover. Ideally you should use nylon, copper or metal bushing. http://www.01mech.com/sites/default/files/images/thread_servo.jpg - Secure the motor cables inside the servo casing using a glue-gun and use heat-shrinking tube to cover them. Assemble the servo including the thread, the styrene bushing and the washers. - Screw-on the cylinder and you are good to go! Here is a video of the small actuator lifting 10kg For those of you that have watched my video on the MTR Rover will understand where the idea of hacking the servo came from ;)) Soon we will be posting assembly instructions, code and schematics on how to modify a standard servo to get full PID speed and position control with 10-bit resolution over 360 degrees – continuous ;) I look forward for your comments!
Posted by Antonb 9 years ago | last reply 9 years ago
I'm building a film scanner using a dlsr. Here's a picture of the rig so far: Basically there's a light source, negative stage, negative holder, camera support stage, camera and lens. I put a negative in the negative holder and slide it using a guide such that I can take a bunch of pictures of the negative at 1:1. For example, it takes 25 pictures to cover a 6x7cm negative. The individual files are then combined into one file using stitching software. The system works very well, but it's a bit tedious. I'd like to automate the negative movement using a diy motorized xy stage. Many of the designs I've seen are for much bigger units, such as for a cnc machine, or units that require speedy movement. That's not the case here. Each movement would be only 10-20mm. I'm fairly handy, and I can follow directions/recipes well, but I haven't worked with arduinos or stepper motors before. Any advice or suggestions on a good way to accomplish my goal would be very welcome!
Posted by pdesmidt 6 years ago | last reply 5 years ago
I want to build a switching Power Supply, without the use of IC's with everything already inside. I only want to use op amps and passive components. Below are my goals on what to achieve. I would like to make this PSU current limited, or at least shut off when the current goes too high. I basically took the concept of the linear voltage regulator and expanded on it, turning it into a 'proof of concept' switchmode supply. Input Voltage range: . . . .7-24 Volts Voltage: . . . . . . . . . . . . . . 5-24 Volts Max Current: . . . . . . . . . .10 Amps Price: . . . . . . . . . . . . . . . . $5 -- $10 Instead of feeding a voltage reference into an op amp, I modulated it with a few components. (A triangle wave generator, and a array of resistors to lower the amplitude and introduce a DC bias.) The DC bias is controlled by the current protection module, which is simply an op-amp that reads the voltage on a small resistor and multiplies it by 5. This finalized current controlled, DC reference biased triangle wave is fed into a comparator, which will then switch a rather large MOSFET on and off at about 200 Hz, with varying PWM, depending on how much 'droop' there is on the output. Here is a rundown of what the components will do: OK, I refined my plan to this general specs: Input Voltage range: . . . .7-24 Volts Voltage: . . . . . . . . . . . . . . 5-12 Volts Max Current: . . . . . . . . . .10 Amps Price: . . . . . . . . . . . . . . . . $5 -- $10 I basically took the concept of the linear voltage regulator and expanded on it, turning it into a 'proof of concept' switchmode supply. I don't want to use any prebuilt chips where you have a magic black box with inductors, capacitors and resistors connected to it. I want this to be entirely raw, basic, cheap parts. Maybe later, I will replace many of the op amps with a single programmable chip (like an Atmega328P) Instead of feeding a voltage reference into an op amp, I modulated it with a few components. (A triangle wave generator, and a array of resistors to lower the amplitude and introduce a DC bias.) The DC bias is controlled by the current protection module, which is simply an op-amp that reads the voltage on a small resistor and multiplies it by 5. This finalized current controlled, DC reference biased triangle wave is fed into a comparator, which will then switch a rather large MOSFET on and off at about 200 Hz, with varying PWM, depending on how much 'droop' there is on the output. Here is a rundown of what the components will do: Green field: This contains a voltage regulator which acts as both a 5V power source and a voltage reference. Not only will this module produce a 5V output, but also produce a triangle wave. Blue field: This module will be fed the triangle wave, decrease it's amplitude, and inject it with a bias voltage, controled by the current limiter (red field). Red field: This basic module simply measures current flowing through a 0.1 Ω resistor, and multiply that reading by a factor of 10, and inert it (the circuitry is probably wrong, and I am not sure how this will work, if it even will do what I want it to Will this work?) Yellow field: The final modulated triangle wave is then fed into the last comparator, which will switch a MOSFET on and off at a fixed frequency of 200Hz. The output of this last comparator is now PWM. As the output voltage sags, the pulse width will increase, and cause the final voltage to stabilize at either the peak value of the triangle wave (with little to no load), or near the bottom end of the wave (with a heavy load) ------------------------------------------------------------------------------------------------------------------------------------ My questions: I try to run this in LTspice simulator but some reason the output of the last comparator is a distorted triangle wave. I think this has to do with my filtering capacitor and MOSFET gate capacitance. Can anyone give suggestions about this design? I'm sure the current limiting function is not going to work as intended until I finalize it's design (I hope I don't need more than 4 op amps altogether, It would be nice to use a single chip I already have) Any suggestions? I might just omit this part entirely, as it is not necessary.
Asked by -max- 5 years ago | last reply 5 years ago
Asked by Rayzor910 8 years ago | last reply 8 years ago
I have a graph, it is not a straight line but a random curve, I want to do linear interpolation of different data set points. I read it here: http://en.wikipedia.org/wiki/Linear_interpolation#Interpolation_of_a_data_set And it says that: "Linear interpolation on a set of data points (x0, y0), (x1, y1), ..., (xn, yn) is defined as the concatenation of linear interpolants between each pair of data points." So. how can I concatenate two or more linear interpolants? And can you please also give an example of it?
Asked by Wisaam 5 years ago | last reply 5 years ago
I got some threaded rods today. They look straight. 16 threads per inch. The tag on one of the shorter ones says 3/8" - 16x36", course threads, zinc plated 1700lb. I was planning to use these for the x,y,z control for a 3d miller/printer. I realize it may be slow. Someone mentioned that the McWire repstrap uses a 4 1/20 (the only part I understand is 20 threads per inch) was really slow, but someone made it work with 2 1/16. I did not really have plans to attempt position verification because I think the resistance vs torque should be minimal for a threaded rod setup. I figure I could get away with just sending it specific pulses for a specific amount of time. Could I have some feedback on this?
Posted by nstenzel 6 years ago | last reply 6 years ago
Antique Bicycle Human Sonar The Linear Clock Learn Business Card Throwing DIY Gorilla Pod Make Whimsical Furniture Kids Riding Crane Gourmet Chocolate Truffles Kill Bedbugs With Christmas Lights Instant Limoncello Cardboard Cryptex Vault $3 Xbox Kinect TV Mount Remove Vinyl Tiles With Dry Ice Challenging Bolt Puzzle Build a Printing Press
Posted by randofo 8 years ago
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?
Posted by ptkrf 4 months ago | last reply 4 months ago
Asked by swupuws 8 years ago | last reply 8 months ago
In electronics, one of the things that has been the most confusing to me is the physics behind transformers. I have learned of that stupid formula a while back, where the ratio of turns is proportional to the voltage ratio and inversely proportional to the current, however, I know from reality that it is no where near that straight forward. As far as I can tell, it is a bunch of BS. Anyway, I want to know what the REAL story is, how the AC current going through the transformer is related to the magnetic flux through the core, and how that relates to the output of the secondary. What seems counterintuitive to me is that more windings on the primary should yield to a stronger magnetic field in the core for a given current, which means for magnetic flux (???) which seems like it should yield to more induced current in the secondary. Is the answer related to inductive reactance (more turns = more inductance = more inductive reactance = higher impedance at a given sinusoidal freq. = less current per unit of voltage?) Note: If you have a good physics and calc background and understand it to heart, pls do explain. However, I am currently only nearing the end of calc 2 w/ absolutely no formal education in physics, so I may have some difficulty with wank terms and vocab. (a.k.a. do not try to show off how many terms you know attempting to explain things in the most complicated and technical way possible.) Also, any good tutorials online that go into depth into the topic? ----------------------------------- The reason I want to know these things is that I wasn't to build a good 6A 0-+/-15V dual isolated channel linear power supply with many transformer tabs so I can keep the voltage drop on the pass elements as low as possible at variable output's so huge $$$ heatsinks are not necessary due to lower low power dissipation. (I have mostly figured out the LPS circuitry, but have not found a suitable Xformer online.) I can get the laminated magnetic cores needed relatively cheaply, however if I have to do some custom windings, I want to make sure I do not choose the wrong number of windings for the core. (obviously one turn on the secondary and 5 turns on the primary will pop a breaker @ 60Hz... )
Asked by -max- 3 years ago | last reply 3 years ago
I am trying to design a nice dual-rail lab power supply and need a cheap dual-output, center tapped, 180VA 18V 5A transformer. The outputs are as follows: Primary: 120V Secondary 1: 9V-0-9V, @ 5A max. Secondary 2: 9V-0-9V, @ 5A max. ======================OR==================== Primary 120V Secondary 1: 9V, @ 5A max. Secondary 2: 9V, @ 5A max. Secondary 3: 9V, @ 5A max. Secondary 4: 9V, @ 5A max. I prefer a transformer for the linear regulator over a switching preregulator, because a switching preregulator sort of defeats the whole purpose of making a nice, high precision, low-noise lab instrument. However, I also prefer to have more than just 2 separate 18V outputs, since that means when the output is shorted and constant current mode kicks in for either the positive or negative rail, I will have a voltage drop of 18V, at a maximum current of 5A, and thats over 90W of power dissipation!!! I think that I can deal with that if thats the only solution, since I am planning on using a large CPU active heatsink for cooling, but I prefer if I was not pushing a TO-247 device to it's thermal limits. I have found this: http://www.antekinc.com/as-2218-200va-18v-transformer/ It is affordable, but it seems strangely cheaper than a lot of other toroidal Xformers on the market. Also, the 2 primaries are not center tapped. It is 200VA though! I have never heard of that company, and it seems like the description of it is written in chinglish. They act like the fact that they over-engineered and under-specced it is a feature (to me, thats how all ratings should be, that should be normal and standard, not a feature.). I have also found this: http://www.digikey.com/product-detail/en/36-6/36-6-ND/1984766 It would be perfect, but it is $80!!! Very expensive, Also, I do not think it is a nice toroidal transformer, not that that matters much to be, I just like the professional look of a beefy toroidal transformer inside a power supply. Lastly, I have found this: http://www.mouser.com/ProductDetail/Hammond-Manufacturing/1182G18/?qs=sGAEpiMZZMvwUzoUXIIvySPCJQuQgm7bYNfLdl9rdUYluBT2%2f%252bFqzw%3d%3d It seems to be very similar to the first find, and it is from a reputable distributor. At $70 it is still expensive, and I do not want to spend over $100 for a homemade power supply. I would just get a off-the-shelf solution for that! What about the possibility of modifying a MOT transformer? How many VA or watts can I expect from the output without active cooling? I know they are rated from upwards to 1000W, but I also know they cannot sustain that power output for a long time without overheating and requiring lots of active cooling, and from what I remember, I believe the core is really being pushed into saturation during normal operation, leading to LOTS of power loss in the transformer core, but can they output 180VA continuously and effectively? Approximately how many turns of wire would I need to achieve my requirements, and what gauge wire should I use? I am thinking 20AWG but someone who has done that before would know better than me.
Asked by -max- 4 years ago | last reply 4 years ago
I'm looking to build a circuit that slows the voltage spike sent to an electric motor. Something that would progressively apply power and progressively power down.It's for a linear turntable. The tone-arm is belt-driven by an electric motor. The issue is, the motor moves so suddenly that it creates an audible 'thump' in the speakers from the quick movement. Would a capacitor in parallel do this?
Asked by CST10 6 years ago | last reply 6 years ago
I'm trying to build a Led Constant Current driver for my led grow plants but I'm stuck on where i would solder the 10k linear potentiomter on the LM317 By the way this is what I'm using 10k linear pot 1kohms fix resister 2.2ohms resister LM317 can someone please draw in color code where i would solder the 10k Pot wires to the LM317 please really appreciate it thank you
Asked by lex76 3 years ago | last reply 3 years ago
I am trying to make a DIY CNC machine, using linear rails and the expert advice in the many awesome instructables out there on this topic. I hit my first roadblock, and I need some help/advice please... The 16mm steel tubes I ordered for the sliding rails wouldn't fit in the 16mm linear slide bearings SCS16LUU that I ordered, they are ever so slightly too big. With a lot of force I could get the rail in the bearing, but it wouldn't slide without extreme force - certainly not the smooth sliding motion it's supposed to be! I've probably ruined the bearings by forcing it in, but I'm not worried about that so much right now (I have spare bearings). I broke out the digital callipers, and the rail diameter measured 16.3mm - that's .3mm more than expected, and more than can fit in the 16.0mm bearings. So now I need to reduce the steel rails by 0.3mm. I have only hand tools at my disposal, and no experience accurately reducing steel rod diameter. I guess another alternative is increasing the slide bearing diameter, but these are sealed bearing units and difficult to get at. Does anyone have any ideas ? Would it be easier to order new steel? Please let me know any thoughts on this, I'm desperate here. Thanks in advance,
Asked by srah1 4 years ago | last reply 4 years ago
I'm looking for someone to help me build an Arduino linear measurement project. I need to measure less than 6" stroke with some accurate repeatability. I'm willing to pay for the programming and any parts I might need. Email me if you are interested in working on this with any questions you have... firstname.lastname@example.org Thanks,
Posted by rpmlou 1 year ago
I want same speed with load and without load? plz ans this question.
Asked by AbdulH63 2 years ago | last reply 2 years ago
Recently I have attempting to design a proper dual-rail power supply that will allow me to set a voltage as low as +-1V up to +-30V in 0.1V increments at (hopefully) 3 significant digits (at least for the lower voltage settings). Anyway, this supply is also going to be current limited to up to 5A,again, it can be set to just about anything. I plan on using an Arduino micro-controller to set the output. In order to do this, I plan on using the analogWrite functions, or better yet, a legit DAC. There will be 4 outputs from the Arduino that will set the power supply output by applying a 0-5V voltage on the input of the 2 current limits and 2 voltage sets. (one for the negative rail, one for the positive). However, I have kept running into the same problem: how do I plan on driving this linear power supply with up to 200W*? My first idea was to use a a MOT, due to their high-power capabilities, and re wind the secondary with the right number of turns to achieve this output. However, I have heard that these transformers are not optimal for continuous running due to their poor and cheap design. (losses are very high). My second idea was to search around for a 250VA transformer. However, even until now, the VA rating confuses me. How does VA compare to W? I know this has something to due with reactive power, real power, and apparent power. However, I have no intuition of any of these 'powers.' How would I go about calculating the correct size transformer for the job, also, I am going to assume this linear power supply has the properties of a resistive load, since it is rectified and smoothed with a filter capacitor, so practically nothing should react with the AC power. (unless there is something more to the full-bridge rectifier setup I am considering.) This is when I came across unwound toroidal cores found on eBay for $25, the perfect price range! However, this has raised more questions! to start off, beyond turns ratio, I do not know now many turns I need for the AC side of things. I know intuitively and from experience, mains-frequency transformers do not work with only one (or even few) winding(s). I think this has to do with saturation, but I'm no expert by any means. and the inductive reactance of the transformer's primary. How do I calculate losses, inductance, and other important parameters of a homemade transformer like this? Things get very nasty when I look back at rewinding an old transformer. Now I have all these questions about inductive reactance, power, currents, magnetic flux and saturation, but also, about determining the original power rating of something like a very old small welding transformer or one from a large 10A car-battery charger. Is it possible to approximate the power by measuring the dimensions of the core? How close will this approximation be? After getting frustrated with this, I considered alternative approaches. What if I purchased 2 ~20V ~6A SMPS (switch mode power supplies) connected them in series, and connect the center tap of my linear supply to the joining point between the 2 SWPS's? Would this be unstable and be bad for the SMPS if a load was connected between the 'outputs' of this new center tapped supply? Would any sort of balancing be required? Also, a bigger problem includes how this will be connected to my linear PSU design. With a low voltage @ high currents, I would be wasting a LOT of power, power that has to be dissipated away from the transistors. This heat can approach 200W, which is company unreasonable! Anyway, I would them have to either a switching preregulator, or modify the SMPS's so the voltage can be controlled easily and varied between, say, 3V to 20V. absolute accuracy is not required, close enough, and rest of my PSU should handle it. This becomes seemingly impractical too, and many other considerations need to be made. What should I do? what are the calculations and factors I need to know? i do not have an LCR meter to measure inductance, so trial and error is out. Does anyone here have experience at this? Help would be greatly appreciated! *The 200W figure was calculated by taking 40V, (What I believe would be a safe to allow some slack for +-5V voltage drop across my 2 shunts and transistors) and multiplying it to 5A of current for the maximum power output. ------------------------------------------------------------------------------------------------------------------- I have added an image of my current design, and I have modularized it the best I could. The YELLOW is all my current power-management circuitry. Currently just a transformer with many taps, going to a currently-undesigned switch box that will change the voltage on the output, which is then rectified and enters a filtering capacitor, finally entering the circuit. The GREEN field is the voltage set. It is the most major part of the PID feedback loop, along with the ORANGE field. It works simply by feeding a voltage to the positive of a op amp configured as a comparator, and with negative feedback from the output. It then outputs a signal to the transistor, turning it either more ON, or more OFF depending on how the output voltage compares to the +Vset. The negative portion is largely the same, but the input voltage needs to be inverted so the output voltage is set negative properly. I was not able to use less than 2 op amps for this portion, unfortunately. The ORANGE field is current set. It works by measuring the voltage drop across the shunt resistor, and outputting a unity voltage that is referenced to ground, instead of to the positive rail. (It took me forever to finalize and perfect that!!!) Anyway, this voltage is then fed into a op-amp configured as a comparator to drive the transistor. The BLUE field is my switching regulation topology, which is controlled by both the ORANGE and GREEN fields. Do you like my use of diodes as a super-simple voltage or current selection switch? the op amp that outputs a lower voltage is the one that gets 'listened to' by the transistors. This way, current and voltage mode enable properly. This does add a small problem when it comes to powering the op amps, all of them have to be powered off of slightly higher voltages to swing the full range due to the voltage drops of those diodes. In the PINK field is simply a single-transistor solution to a constant current load. This allows the regulator to be regulated even at very low voltage set levels. This is why I am able to achieve a +-0.5V on the output (at least within LTspice) Finally, and most unimportantly, the light PURPLE fields have a simple ultra high-gain difference amplifiers that will detect if the output current and current set are the same, and turn On or OFF the respective LEDs. The green LEDs are voltage-mode indicators, and the red LEDs are to show when current-limiting mode comes on.
Asked by -max- 4 years ago | last reply 4 years ago
Ok I'm experimenting with tops and linear transformers for therapeutic effect these seem to be the best combo so far could some aproximate what kind of signal is being out put with a step up linear transformer 4:1 and does it just feel good to me and disruptive to telecommunication it doesn't interfere with wifi
Asked by wiccakingkamui 5 years ago | last reply 5 years ago
I am going to build a small linear accelerator like the one rutherford used to bounce alpha particles off of a sheet of gold foil. Actually that is exactly what I am going to make. The only thing is that I am not sure how I would generate the electrostatic field. Would a van de graaff generator work, or would I need something different? if I do need something different how would I make it?
Asked by Higgs Boson 7 years ago | last reply 6 years ago
Contact me if you are interested in any of the rigs listed. Amps and Repeaters , Icom IC-PW1 Linear amplifier, HF+6m 1kW solid-state Kenwood TS 2000 Kenwood TS 990s Elecraft K3 Elecraft KX-3 FlexRadio 5000a FlexRadio 6300 Icom IC 7800 Icom IC 756 Pro III Icom IC 7000 Acom 2000a Icom PW-1 Email :email@example.com Pictures and price available on request. (73)
Posted by BECKONX 3 years ago | last reply 3 years ago
I am building a stewart platform as part of a larger assembly to accuratly position an object in all six degrees (transition in x,y,z) and rotation about each of these (pitch, yaw, roll). I plan to use an arduino board and 6 firgelli linear actuators. Any help on how to go about programming this would be a great help, or if anyone knows of any open source code so that I do not have to do the reverse kinematics as Im not strong enough in math to do so. ive attached a pic screenshot of my design. thanks
Posted by habbi_88 6 years ago | last reply 2 years ago