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Old May 10, 2012, 03:32 AM
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bob_nj's Avatar
Vineland, N.J.
Joined Sep 2003
739 Posts
Question
How to test a motor or speed controller

Either the ESC or the motor on one of my foamies took a dump.
I'll do a search, but in the mean time thought I would ask;

What's the best way to test either the speed controller or the motor to see which
is the culprit?

Thanks
Bob
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Old May 10, 2012, 03:50 AM
We want... Information!
Bruce Abbott's Avatar
Hastings, New Zealand
Joined Jan 2001
5,193 Posts
Substitute. Try the ESC with another motor and/or the motor with another ESC.

You should also check them for physical indications of failure. The motor could have a broken wire, or one of the connectors might be loose or poorly soldered (which usually causes the motor to jerk back and forth but not start up). Check the ESC for the same things, and also for signs of burning. If the ESC smells burnt, then it probably is!
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Old May 10, 2012, 03:52 AM
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I should have mentioned that I don't have extra equipment to substitute.

Thanks for the reply
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Old May 10, 2012, 08:18 AM
Jack
USA, ME, Ellsworth
Joined May 2008
17,219 Posts
What happens when you turn the TX on and then connect the battery to the ESC? Are there any sounds at all?

Don't open the throttle unless you get the normal arming tone, a bad motor can kill a ESC. A bad ESC is less likely to kill a motor though.

Everyone needs a multimeter, they are as cheap as $3 on sale at Harbor Freight. Do you have one?

Jack
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Old May 10, 2012, 08:23 AM
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Vineland, N.J.
Joined Sep 2003
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There is no noise from the motor at power up.

I have a boatload of meters and test equipment.
Just don't know exactly what to test??

Thanks
Bob
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Old May 10, 2012, 11:27 AM
Jack
USA, ME, Ellsworth
Joined May 2008
17,219 Posts
Quote:
Originally Posted by bob_nj View Post
There is no noise from the motor at power up.

I have a boatload of meters and test equipment.
Just don't know exactly what to test??

Thanks
Bob
If you set a multimeter to RX1 and check the three motor leads in pairs (1-2, 1-3, 2-3) you should see a steady, very low resistance there. It will be almost the same as you see with the probes shorted. If any of the reading dance and change or are considerably higher there is a short between the windings.

And if you find a bare spot on the stator for one probe, you can check all three motor leads for shorts to the stator. Either of those kinds of faults can keep the ESC from arming. And if you open the throttle with those kinds of faults you can kill off an ESC. I like to do those tests with the biggest ESC I have around and only open the throttle one click and momentarily to see if it will run.

Beyond those checks, I would try another ESC which I now know you don't have.

If you remove the throttle/BEC lead from the receiver you can check the red and black leads on that to see if the BEC voltage (5-6V) is present. That will give you an idea as to if the BEC power supply is dead and, if it is, there is a good chance that rest of the ESC is totally dead too.

More trouble shooting procedures here too:

"Dry Testing" brushless motors - http://www.wattflyer.com/forums/showthread.php?t=35216

I have never tested the motor leads on an known good ESC and motor with a meter to see what the voltage indications on the motor leads would be. But I'm pretty sure that if the ESC is not arming there would not be anything on those leads.

Jack
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Old May 10, 2012, 11:32 AM
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Vineland, N.J.
Joined Sep 2003
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Thanks for the info!

I'm going to try to make it to a local shop today after work and pick up some stuff to figure this out.

Take care
Bob
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Old May 10, 2012, 11:55 AM
Jack
USA, ME, Ellsworth
Joined May 2008
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The ESC not making any sounds at all kinds of makes me think that the problem is there initially. All of my ESCs do something when you plug them in even if they don't carry on through to the arming stage.

And the noises come from the motor, not the ESC. They sort of "buzz" the windings against each other. So if there is no motor connected and no LED indicators on the ESC, you might not get any indications at all.

Jack
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Old May 10, 2012, 11:58 AM
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Vineland, N.J.
Joined Sep 2003
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The plane and accessories are on the bench.
I'll try to get a good assessment of what's going on and let you know.

Thanks a lot!
Bob
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