Are there any physical signs when a brushless motor packs up? - RC Groups
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Jun 17, 2011, 12:23 PM
Yo Mamas toy boy
CaptainCarling's Avatar

Are there any physical signs when a brushless motor packs up?

I suspect my motor has given up as the ESC has smoked.
Long story, but ive had the motor off and there doesnt appear to be anything wrong with it
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Jun 17, 2011, 12:54 PM
Cranky old fart
Balr14's Avatar
Depending on the heli, the ESC is often the weakest link. Many helis, especially with belt or shaft driven tails, come with an ESC that can't handle the load. It's pretty common to use a separate BEC for the tail and gyro, to reduce the load on the ESC.
Jun 17, 2011, 07:27 PM
dont play with rc anymore
micronut's Avatar
Not really. Sometimes the coils will be blackened, but usually no way to tell.

Best to rewind or replace.
Jun 18, 2011, 03:32 AM
Yo Mamas toy boy
CaptainCarling's Avatar
Thanks guys
Jun 18, 2011, 04:14 AM
Registered User
The usual reason for the esc to smoke, is a broken coil due to heat, this transfers the load to the remaining coils. Higher current, means higher temperature and most esc are quite sensitive things... In a normal outrunner, wired in star or delta all the trailing wires of the motor are common. The quick way to check if your coils are sound is to continuity check between all the connecting leads of your motor. No continuity...bad motor...

Jun 18, 2011, 05:48 AM
Yo Mamas toy boy
CaptainCarling's Avatar
There seems to be continuity, but there is a small amount of play in the bearings (pinion end)
Jun 18, 2011, 12:45 PM
Zippy Puffer
2Doggs's Avatar

Beware of screeching!

I've not had any ESC's fail yet, touch wood, but I've had a motor fail. First of all, it started to run quite noisily, and it turned out that the bearings were spinning in their housings. When I took off the motor can, I could see that the play that had developed had been enough to cause the magnets to rub on the stator, and there was quite a bit of magnet dust in the can. I got a bit more life out of the motor by using threadlock to fix the outer races in the housings, but I could also see that the motor shaft was also worn down a bit where it had been spinning in the front bearing. I bodged that with more threadlock.

After a few more flights, the motor failed - the shaft broke off at the front bearing, causing me to do my first and only auto to date with my 450.

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