How To: Check a Motor Armature for Damaged Windings
Detach the Motor From Its Machine Housing. Remove the DC motor from its machine housing so the rotor can move freely during diagnostics. Depending on the motor type, you’ll either have metric or SAE bolts, so make sure you have the right tools for the job. 3. To test your DC motor, touch the leads of the ohmmeter to the leads of the motor. The meter's screen should indicate a low resistance (somewhere between 10 and 30 ohms), but if it reads an infinite ohms or an open circuit you should rotate the end shaft of the motor.
Electrical Engineering Stack Exchange is a question and answer site for electronics and electrical engineering professionals, students, and enthusiasts. It only takes a minute to sign up. Connect and what causes breast cancer recurrence knowledge within a single location that is structured and easy to search.
We have had some motors start to smoke a couple of times. How can I test the motors we have to find out if they are good? Measure the resistance between the motor terminals and compare it with a known good motor or the datasheet.
If the coils have melted, they will have shorted and you'll see a lower resistance. Or they will have broken altogether, and you'll read infinite resistance. Turn the axle of the motor with your fingers and compare it to a known good motor. A bad motor can sometimes stick, or feel like it's got a lot of friction. Finally, connect a known good motor to a variable voltage power supply. Turn the voltage up slowly from zero, up to the motor's rated voltage. See how the motor behaves. Do the same for the suspect motor.
Compare them. I was on a FTC team for 4 years. What I have learned about the motors, is that when you see the "Magical Smoke", it is actually a resistor inside of the motor, and can be fixed by opening up the motor and replacing the resistor.
These motors are extremely susceptible to burning out when they are over driven. Take care not to use two motors on the same gear set, use the "big" gears with the "little" gears in a high torque situation, or to drive the motors under high torque for a long period of time running into a wall, and keeping the wheels moving. It will not hurt the motors in any way. Once you see smoke, the resistor inside has already been destroyed, and the motor is no longer going to operate like new.
It may not be what you want to hear, but you are better off only using the "smoked" motors for testing components, and replacing the "smoked" motors on your competition robot. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Learn more. How can I test a dc motor? Ask Question. Asked 9 years ago. Active 9 years ago. Viewed 14k times. Improve this question. Jon Jon 33 1 1 gold badge 1 1 silver badge 3 3 bronze badges.
Add a comment. Active Oldest Votes. Improve this answer. Rocketmagnet Rocketmagnet Reid Reid 1, 1 1 gold badge 18 18 silver badges 37 37 bronze badges.
Depending on how long the the motors "smoked", will effect at what percentage the motors will work. There are ways to test the output of the motor, but it is tough and expensive. As I said above, my team and I aired on the side of Caution, and although it cost more money in the long run, our robot functioned well. Sign up or log in Sign up using Google. Sign how to check dc motor using Facebook. Sign up using Email and Password.
Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Non-fungible Talking. Featured on Meta. Stack Overflow for Teams is now free for up to how to play ufc undisputed 2010 ps3 users, forever.
New onboarding for review queues. Related 6. Hot Network Questions. Question feed. Accept all cookies Customize settings.
Jul 14, · DC (direct current) electric motors are used in many applications. Test the meter by touching the two leads together; the meter should read zero ohms or full continuity. Touch the leads of the meter to the two motor leads. The meter should read a . Measure the resistance between the motor terminals and compare it with a known good motor (or the datasheet). If the coils have melted, they will have shorted and you'll see a lower resistance. Or they will have broken altogether, and you'll read infinite resistance. Sep 17, · You can check your continuity with an ohm meter. For brushes/commutator, your best check is visual. A high speed or heavy duty motor can see problems where the rotor conductors are crimped into the comm segments. If the motor is dissasembled and you have a growler available, you can test for shorts within the windings.
The good news is that if your issue is with a DC motor, troubleshooting one is pretty easy. That said, you should know what to do before something goes wrong so you can get back up and running as soon as possible. Use a screwdriver to remove the set screws from the wire connections running between the motor and battery.
If necessary, expose the ends of the wires so you can use them to complete the test circuit. Remove the DC motor from its machine housing so the rotor can move freely during diagnostics.
Set the volt-ohm meter to its ohms setting. Plug the red volt-ohm meter lead into the ohms point, and the black lead into the ground point. Attach the alligator clip leads to each motor power input wires. Touch the two leads together and ensure the volt-ohm meter reads zero ohms. Touch the exposed wires of the motor with the volt-ohm meter leads.
Black goes to black and red goes to red. Now, read the screen and determine the results:. Infinite ohms: This means there is an open circuit and requires further testing. If the meter shows an open circuit, there is a short in the ground. Locate the motor bushings under the plastic end caps on the other side of the driveshaft. Use a screwdriver to remove the bushings and then inspect them. Look for cracks or breaks across the surface of the bushings.
There should be a smooth curve where the bushings sit against the commutator. If you find no defects, the problem is usually the commutator. Remove the two screws that run the length of the motor and take off the rear end cap. Inspect the plates that make up the commutator assembly. You should see an opening between each plate and no broken wires or burnt varnish. Each motor comes with an electrical warranty and has been rebuilt to prime working condition.
Review this GE Table Motor Guide for more information about our offerings or contact us anytime with questions. Prepare the Volt-Ohm Meter for Testing. Now, read the screen and determine the results: 10 to ohms: This is a low resistance range and indicates there is nothing wrong with the motor. Test for a Short in the Ground. Remove and Inspect the Bushings. Remove and Inspect the Commutator.
Posted in Industrial Equipment.