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odd problem with electric motor

#1
Hi, recently I was flying my plane, and upon landing it, noticed smoke coming out of the left nacelle (2 engine airplane). I immediately unplugged the airplane and once I was able to tear open the bottom of the airplane, learned the ESC had caught on fire. I just now replaced the ESC, figuring the other one was cheap and getting old anyway and when I was testing the motors, saw that the left motor wasn't spinning, just jerking irregularly, and the ESC was getting hot, so I unplugged it and was fiddling around with the connections and prop when I realized theres a weird amount of resistance in the motor. I have no idea why though, it's weird. I now have it mostly disassembled, the bearings seem to be working and the shaft isn't bent, so it seems like some type of magnetic resistance, however this occurs when the motor is completely unplugged, and I can't figure out why. I assume this is the cause of the ESCs getting hot, as it's feeding the motor current but the motor isn't using it because it can't spin. any help is welcome and thanks for your time.
 

Merv

Well-known member
#2
Sounds like you may have some type of foreign matter inside the motor. While you have the motor apart, take a an old toothbrush and clean the magnets.
 

quorneng

Well-known member
#4
If it was the motor that smoked it could have damaged the insulation varnish on the stator windings. If there is now some internal short circuits the motor will feel like the ESC has applied the brake which it does by shorting out a pair of windings!
In this case a new motor is the only solution but in any case you need to find out what caused it to smake in the first place otherwise the replacement will fail in the same way.
 
#5
If it was the motor that smoked it could have damaged the insulation varnish on the stator windings. If there is now some internal short circuits the motor will feel like the ESC has applied the brake which it does by shorting out a pair of windings!
In this case a new motor is the only solution but in any case you need to find out what caused it to smake in the first place otherwise the replacement will fail in the same way.
the ESC was thoroughly burned, but when I plugged the motor in with a new ESC it just kind of buzzed and the new ESC stared to get hot too so I quickly unplugged it. if something did melt inside, is it fixable?
 

FDS

Well-known member
#6
Nope, once the smoke is out that’s it.
I would throw that motor, it’s clearly shorting. A smoke stopper is a good idea that will save you component damage in future.