how do you know how many rpms your engine has?

Such as a weedeater.

Question by TSC 7 years ago  |  last reply 7 years ago

is there any way to measure rpms cheaply?

We are making wind turbines in one of my classes and my team is making a tesla turbine as ours. we want a way to measure how fast the disks are spinning. please help.☺

Question by DehLeprechaun 8 years ago  |  last reply 4 years ago

Air Compressor RPM? Answered

I found an old cast iron 50 + year old 2 stage air compressor and I was wondering what RPM's I should run it at.  My dad says it is running much slower than he remembered and it is going 323 RPM's compared to the original gear ratio that would have run at 269 RPM's.  That should be dramatically faster, so could going too fast decrease performance, or something, or is there a reason the original motor may have slowed down? The RPM's are a complete guess based upon the 1725 RPM motor average.  The only reason I had to change pullies was because the original had FLAT BELTS (awesome) from back when people cared and build stuff right.  Now I have a v-belt on it and the compressor pulley wobbles by like 2 inches and the thing is out of line, but these shouldn't be slowing it down. Basically I need to know what RPM's I should be running the compressor at. P.S.  It can double as a vacuum  pump and it uses old fashion check valves!

Question by 6 years ago  |  last reply 6 years ago

RPM of K'nex engines? Answered

Does anyone know the revolutions per minute for the K'nex electric motor (grey one with mains adapter) and the revolutions per minute for the K'nex tethered battery motor (same as standard battery motor I think). Electric one is first picture, battery one is second picture.

Question by The One and Only 9 years ago  |  last reply 9 years ago

RPM/MPH formula

I'm designing an anemometer with Arduino and I need a formula to figure out the speed at which the rotor turns. I have a rotor with three magnets, spaced 71mm apart, triggering a Hall Effect sensor which the Arduino reads and counts. Now I can't seem to figure out a formula to calculate wind speed from this information. Anybody got an Idea (or the answer?)

Topic by smkoberg 8 years ago  |  last reply 8 years ago

50k RPM with DIY Motor?

Has anyone built an electric motor that can reach 30-50k RPM? Would you think it is possible to build one?

Topic by Tyoon 6 years ago  |  last reply 6 years ago

Can a transistor amplify a motor's RPM?

Question by PKTraceur 10 years ago  |  last reply 9 years ago

how to control the rpm of pmdc motor?

Question by vickyraja 5 years ago  |  last reply 5 years ago

What's up with slow rpm motors? Answered

What's the deal with slow rpm motors? I need one for a project and can't seem to find any online. Why not? Am I looking in the wrong place?

Question by noahh 10 years ago  |  last reply 10 years ago

How to find the rotating shaft rpm?

I have used AC motor of 750 rpm... motor then transmit its power to gear box then to shaft... on shaft rope drum is connected to do the required work i-e lifting or lowering of load

Question by waseemhaider.syed 3 years ago  |  last reply 3 years ago

Measure RPM and MPH on motorcylce with Arduino

Hi all, I have an idea for an Arduino based instrument cluster for my cafe racer (1980 xs400). My question is what kind of rotary encoder I should use to measure the rotation from the cables coming from the engine block and front wheel that went to the original cluster (shown in pictures). I want something that won't break at higher RPMs and is more or less water proof. I have an idea of how to code this on the software level as well, but I'm not to experienced with C/C++ so any help there would also be appreciated. The end goal for this part of the cluster is to output the RPM and MPH to respective WS2812B 5050 LED strips, and possibly a small oLED later down the line. If something could be made more clear on this post let me know and I'll try to elaborate. Thanks again

Question by AedanGraves 4 months ago  |  last reply 4 months ago

Stepper motor high speed(rpm)?

I need a high speed (rpm) stepper motor but i don't exactly know where and what to look for. I have recently assembled this project for a laser harp : I have finished everything but the stepper motor parts. The stepper motor I had ( 28BYJ-48 – 5V) had a high torque but was far too slow to split the beams properly. My stepper motor shopping has left me more confused than when i started. Where can I find a quick stepper motor that can run on say 5-24 volts? It seems the stats rarely include speed or rpm. Thank you for any help in the matter.

Question by TheIronHobo 5 years ago  |  last reply 2 years ago

Reducing speed / RPM of pedestal fan

I have a 400 mm pedestal fan rated for 230V 50Hz AC, 120W with minimum 2200 RPM which uses motor coils winding for speed regulation. Its speed and noise is very much even at lowest setting. I want to reduce its speed even further. I am thinking of three options - one - changing the OEM fitted 3.00 micro-farad 440V capacitor with 1.5 or 2.0 micro-farad 440V capacitor, second - using a capacitance based speed regulator (used with ceiling fans) and the third - using a resistance based speed regulator (least preferred option though). Please tell which option will work fine without doing any harm to motor coil? Any other options are highly welcome.

Question by sharmavk83 11 months ago

Which Low RPM Gear Motor?

I am working on a robot that will have a grabbing claw, of sorts, and I'm not sure what gear motors to use to actuate the claw.  It needs to have significant gripping power, so the gear motor must be low-RPM and high torque.  The two best options I have found so far are these: 1. 12VDC Gear Motor, 7 Rpm 2-7/16" x 1-5/16" Dia. 2.  Tamiya 70110 4-Speed Crank-Axle Gearbox Kit   If I used the Tamiya gearbox, I would also have to buy higher voltage motors, so the cost of the two is approximately equal.  Because of its layout, I think the Tamiya would be easier to use, but I'm worried about stripping the plastic gears.  Also, I have a smaller Tamiya gearbox, and the axle has some play in it and is extremely noisy. The 12V gear motor, on the other hand, appears to be more robust and probably has metal internal gears, but it would make my robot a bit larger. Does anyone have experience with Tamiya gearboxes?  How do they handle high loads?  If anyone has any input on these two choices, or other motors you think would be even better, I'd really appreciate the help.  Thanks!

Topic by ben_k 7 years ago  |  last reply 7 years ago

how do i find the rpm of a rc plane?

Question by RcMaKeR 8 years ago  |  last reply 8 years ago

General question about controlling car engine ??? Answered

Hi ... I would like to ask, how do call the "thing" that control RPM of your engine ??? What I mean ... there is something - kind of small motor, that controls the RPM. When you start your engine and you don't have any gear it holds the RPM on cca 1000 RPM. But in winter (when the engine is cold) it brings the RPM to 1500 ... and then, when the engine becomes warmer, it decreases the RPM. 1. How do you call the part, that controls these RPM ??? 2. Is there any restriction that says what is the maximum RPM that this "small motor" can provide... like it will not make more then 2000RPM ... or you could set it up up to 7000RPM as well ??? Thank you in advance...

Question by zholy 8 years ago  |  last reply 8 years ago

i want to make low rpm less torque 1kw generator or alternator?

Can someone please tell me that how to make 1kw low rpm generator or alternator , please tell me the specs of  generator or alternator which is easy to build and takes low rpm for power generation actually i want to make a generator or alternator which needs less torque and rpm , so please tell me the specs for making low rpm less torque generator or alternator specs like how much magnets do i need shape , quantity , grade of a magnet , rpm of a magnet , torque  , gauge of a copper wire , turns of a copper wire , quantity of copper coils , distance between copper coil and magnets etc ( i want rpm of a 1kw generator or alternator  to be 80 -100 rpm )

Question by MuhammadK19 3 years ago  |  last reply 3 years ago

is the 250 rpm dc motor is good for electric bike??

Is the 8kg-cm and 250 rpm dc motor is good for electric bike??  hi i have a 12v dc geared motor 250 : rpm 8 km-cm : torque is this good for build ebike ??

Question by ShocoM 3 years ago  |  last reply 3 years ago

how much rpm is needed to generate electricity of 3v?

Question by vdrit 5 years ago  |  last reply 5 years ago

Use brushless DC motor (or stepper motor) as RPM sensor?

Hi all, I'm making an Arduino based digital instrument cluster for my 1980 XS400 motorcycle. all the old tach and speedo instruments are mechanical so I need to convert the spinning cable's rotation to digital RPM. I've tried IR tachs but I can't seem to get them to be accurate enough (the lowest RPM I could get out of them was about 375, which isn't low enough) I'd love to use a more mechanical means of getting the RPM. could I use a 3 phase DC motor to count RPM? if I can, how?

Question by AedanGraves 2 months ago  |  last reply 2 months ago

how to increase rpm of 3v dc motor for making airplane? Answered

Question by balodabazar 8 years ago  |  last reply 2 years ago

ntc thermistor for auto rpm pc fans

I have 470 ohm thermistors and i want to auto control my pc fans ie when the temperature is low the fans are off or low speed,when temperature go high the fans rpm follow there a scematic how to do a pcb?

Question by napoleonis 9 years ago  |  last reply 8 months ago

Variable, low-RPM DC motor setup?

Hey guys, I'm hoping to build a motorized slider system for my DSLR camera. I'm going to build the slide from scratch and probably attach a motor with a pulley system to move the slide, this should give me the option of having the camera climb the slide if it's on a slight angle. I'm not extremely electronically inclined but I understand I will need a low RPM motor and a PWM unit to adjust the speed. I'm thinking RPM between 0.5 & 10 would be ideal. Could I buy one of these ( add a 12v battery and a 12v DC motor and call it a day? If this is the case, should I be aiming for a 10 RPM motor that I can turn the speed down on? Is a 12v battery/motor likely to give me reasonable torque for dragging a DSLR camera up a moderate incline? Battery life shouldn't be an issue as the longer the use the less RPM I'll need. Any thoughts would be much appreciated.

Question by tig5 5 years ago  |  last reply 5 years ago

Will a leak in my muffler cause rpms to increase slightly ?

This happens in neutral as well as when in gear.  Only talking 2-300 rpms in each case.  Will be replacing muffler tomorrow regardless.

Question by BOB J 9 years ago  |  last reply 9 years ago

why machine maximum tortion happened at low rpm?

What caused it happened

Question by ririd 10 years ago  |  last reply 10 years ago

Changing LEDs colours as a car goes up in RPM?

I'm buiding a buggy and would like to build a visual effect when going up through the RPM and have some LEDs in the back change colour as i complete in the night events,    My question is there  away of building a system that  runs off the aultnator as the RPM rises it changes the colours in the light out put

Question by Bazzabushmechanic 6 years ago  |  last reply 6 years ago

How can I limit the RPM of an electric motor by using resistors or trimpots? (cheap/simple way)?

I've done it with a small trimpot that almost ignited by heating. What the problem? The current is to high? To lower the RPM must i lower the current or the voltage? And what exactly do the resistance lower? voltage or current?

Question by vinacarv 9 years ago  |  last reply 9 years ago

which has high rpm and torque, the 3v dc brushed motor or the 12v brushed motor, they are running the same at 6v battery

Is it advisable to use a 12v motor to have high torque and rpm than a 3v motor?they both run at 6v,

Question by antitaengbasuraman 9 years ago  |  last reply 9 years ago

do turbine generators have a maximum rpm or does it just produce more energy the faster it spins?

I am trying to find out if wind turbine generators have a maximum rpm or if they just keep producing energy. if so, my next question would be, does generators maximum output have a maximum rpm. if it spins too fast because the wind is very strong that day, will it affect the turbine and cause it to overheat?

Question by chokeonthis 9 years ago  |  last reply 9 years ago

Speed sensor

I have a 60 tooth ferromagnetic ring gear with a speed sensor attached. Each passing of a tooth creates a pulse in the sensor sending a signal to the ecu for calculation of attained rpms. It calculates the interval between the teeth to obtain the rpms, thus determining when to kick in the rev limiter on my 06 polaris ranger XP 4x4. Is it possible or even practical to eliminate every other tooth to "fool" the sensor into a lower rpm reading, and creating higher rpm levels within the motor?

Topic by hiatt65 12 years ago  |  last reply 12 years ago

do bigger wheels wih same rpm make a rc car faster or slower? Answered


Question by albf1 9 years ago  |  last reply 9 years ago

How can I calculate the RPM of a motor running at less than Maximum voltage? Answered

I'm working on a project that needs a certain RPM of motor. I am looking at motors from I will be running these motors at ~5v. Is there an equation I can use to calculate this sort of thing?

Question by sblaptopman 7 years ago  |  last reply 7 years ago



Question by RAGHUL NM 4 years ago  |  last reply 4 years ago

DC motor regulation

I am planning to build a small gearbox that depends on a steady rpm from a 3V dc motor. I understand that the output rpms will change in correlation to the fluctuation of input power. My question is, if I used a regulator to regulate the input voltage from 5V to 3V, will that keep the motor rpms steady?

Topic by Tman179 1 year ago  |  last reply 1 year ago

flywheel pulley size?

I need to know what size compressor flywheel pulley to use for a 3450 rpm motor compressor 1500 rpm dia. 13 3/4"

Question by block1102 5 years ago  |  last reply 5 years ago

Difference between 12V & 6V dc gear motor of same rpm?

Difference between 12V & 6V dc gear motor of same rpm?

Question by akshaykumar12 1 year ago  |  last reply 1 year ago

DC motor with 30nm torque and more than 3000 RPM

Hi I need DC motor with 30nm torque and more than 3000 RPM how to build this or form where I can buy this in India please guide me on this also tell me what should be battery specifications to run this for 100km with the total load of 250kg?

Question by BhuvanS6 1 year ago  |  last reply 1 year ago

Arduino calculation error... Or operator error?

Below is a tachometer program that was patched together... Using a hall effect for the sensor. For some odd reason when the calculation is done for interrupts per second something goes wrong... When set at 30*1000 I get what seems to be a good RPM number... But when changed to 60*1000 the RPM jumps to 20-50k... Not sure what is going on... If someone would be so kind and have a look at the program and see if I am missing something... It would be appreciated.. int ledPin = 11; volatile byte rpmcount; unsigned int rpm; unsigned long timeold; #include LiquidCrystal lcd(8, 13, 9, 4, 5, 6, 7); void rpm_fun() {   rpmcount++; } void setup() {   lcd.begin(16, 2);   attachInterrupt(0, rpm_fun, FALLING);   pinMode(ledPin, OUTPUT);   rpmcount = 0;   rpm = 0;   timeold = 0; } void loop() {   delay(1000);   detachInterrupt(0);   rpm = 60 * 1000 / (millis() - timeold) * rpmcount;   timeold = millis();   rpmcount = 0;   lcd.clear();   lcd.print("Rotary Head RPM:");   lcd.setCursor(6, 1);   lcd.print(rpm);   if (rpm > 100)   {     digitalWrite(ledPin, HIGH);   }   else   {     digitalWrite (ledPin, LOW);   }   attachInterrupt(0, rpm_fun, FALLING);

Question by fracture123 3 years ago  |  last reply 3 years ago

Slow down a DC motor?

Here is another basic electronics question for all of you: What is the easiest way to slow down the RPM of a small DC motor? Much appreciated!

Question by brandegor 9 years ago  |  last reply 3 years ago

Arduino LDR tachometer (RPM counter)- not sensitive enough ?!?

Ladies & Gentlemans  ... I would like to ask you, what I'm doing wrong, in this RPM counter ??? As mentioned in my previous questions, I 've got an ARDUINO and I started with my first part - of my project. To count RPM / or speed. I'm using a LDR (light dependant resistor) and green laser as light source. The scheme is like this: + 5V ------- LDR -------------Analog pin 1                                     \                                       \--------resistor (220kOhm) --------- GND The code for this project looks like this : int LDR=1; // LDR is on analog port 1 int val=0; // this is the value, I get from the LRD void sextup(){  Serial.begin(9600); } void loop() {  val = analogRead(LDR); // read the value getting from LDR Serial.println(val); if (val<1018) {delay(4000);} } To explain the value 1018 in the IF condition ... when pointed the laser on the LDR,I get value from 1019-1020. So my idea was, when the value decrease just by one or more ... let me know, that the laser beam has been interrupt. But I realised, that I can cross the laser beam very quickly, and the LDR/Arduino will not notice it. I really don't know, where I'm going wrong. My few suggestions are : 1. wrong method - to use LDR ... should I use something else ??? 2. wrong RESISTOR value ??? ... should I change to different value to make it more sensitive ??? (I tried 2 different values = 220kOhm, 46kOhm ... that's what my voltmeter said :) ... but with both of them I have the same result ) 3. should I use different code ??? Any ideas ??? Thank you in advance for your answers. Zholy

Question by zholy 9 years ago  |  last reply 9 years ago

How do I calculate the RPM of a electric vacuum motor?

I have a Johnson 12amp 120v 60Hz vacuum motor that I scrounged out of an out of commission vacuum cleaner and was curious of its RPM's to see how it would have to be geared to fit my project needs. If anyone out there can help me please speak up.

Question by greensmith7 9 years ago  |  last reply 6 years ago

What is the power of a battery required to run a motor of 2750 rpm motor?

Pls tell me the power of a battery with which a motor of 2750 rpm motor runs? What exactly will be the weight of that battery?

Question by karthiknune 2 years ago  |  last reply 2 years ago

can ducted propeller produce twice lift compared to opened propeller ?

Can ducted propeller produce twice lift compared to opened propeller ? for example if there is an opened propeller with low rpm producing some amount of lift. If we ducted that opened propeller and provide same rpm and power as opened propeller to it will it produce twice lift compared to opened propeller with same rpm and power ?

Question by MuhammadK19 2 years ago  |  last reply 2 years ago

i want small size 3000 rpm motor capable of running with a battery?

What size of battery is required for it  capacity of battery  what could be possible max weight of battery

Question by somfire 6 years ago  |  last reply 6 years ago

Need a Motor for ASTM testing: 1-5 RPM, ~150 lb in of torque. Any ideas?

I need a motor with low speed and high torque as described above. Thinking about using a 12V power supply but I'm flexible there. I've tried gear motors but I can't find any with the characteristics I need. The application: motor needs to turn a screw that is fixed until the screw fails. After I have the motor I need I'm gonna have to find some way to graph the torque vs. speed curve. Can't spend a fortune but willing to spend up to $100 because it's time critical. Summary: Needed RPM: 1-5 RPM Torque: 150 lb in Cost <=$100 Thank you so much for any suggestions!

Question by nkay3 6 years ago  |  last reply 6 years ago

how do you build a rpm meter and what is it called? Answered

Iv been tring to design a time mechine for a few months now and the best solution to this problem that i could find was gravitational time dialation this is the thery inwich gravity slows time down inside the gravitational field. to do this i decide to build a big centrofuge with a power full motor but to do this i will need a rpm meter to mesure the angular velocty of the centrofuge but the bad part about this is i dont know where to buy 1 so i ducided to build 1 but i need 1 that feed data into a laptop through a usb port 

Question by lj123456 9 years ago  |  last reply 9 years ago

How many RPM does it take to reverse the process of a 1.5V DC Motor? Answered

I excavated a toy train and pulled out a 1.5V DC Motor. I have not found a use for its motion, so I was thinking of reversing the process and creating a hand crank flashlight. But should I hand crank? How many RPM would it take to generate its standard voltage? Thank you for your answers.

Question by DELETED_explosionist 8 years ago  |  last reply 8 years ago

how can I make a dc motor spin with less rpm's to get started?

I took a DC motor from a electric mower and want to use it for a wind generator. But I need it to spin with less starting rpm's. How can I do this? I guess what I am trying to say is I need it to start moving in about 3-5 mph winds vs's 13-15 mph winds.

Question by swat420 9 years ago  |  last reply 9 years ago