Phase wire shorted - motor dead, ESC survived

#1

Howdy,

I just recently kissed the pavement. What happened you ask? One of my motors shorted. Well, at first I had a sudden drop of torque and the ESC shut off. After turning it back on - I had no idea what was going on at that moment - I could ride but very stuttery. Something definately wasn’t right. (oh, I’m riding a dual setup with 2 flipsky 4.12 and 2 maytech 6355 190Kv motors via CAN on a 10s4p 30q battery, btw).
I was on my way to University so I been heading straight to the shop to have a closer look at the situation.
Strange to me at first was the fact, that both motors been acting up. Symetrical behavior. After a few seconds of mild throttle they dropped power and gave me FAULT_CODE_ABS_OVER_CURRENT. Since they are connected via CAN my first thought was checking either the master ESC or the motor connected to it.
Some cross checking later I figured this:

IMG_20200214_135104
IMG_20200214_1351042610×4640 4.47 MB

Clearly one phase was overheating.
The cause is this:
InkedIMG_20200214_142443_LI
InkedIMG_20200214_142443_LI4640×2610 2.84 MB

In case you don’t see it - one of the phase wires shorted against the motor housing. Propably due to vibration.
Sucks pretty much since I been riding them only for like 400-500km.

My questions now:
How do I prevent this kind of failure in the future and since I obviously need at least one new motor - which one to pic? APS? Torqueboards? Sealed and water resisting bearings would be a nice upgrade ;D

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#2

Could help if you epoxied them in place when you first get them

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#3

Hmm
meaningful
:thinking:

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#4

ouch, same motors ive got basicly - i did indeed battle harden them, but the area that shorted for you, i did not touch :thinking:

time to whip up some epoxy,

thx for the heads up!

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#5

while that can is open, can you measure the stator lenght ?
wanna compare to the 6374 version

and while im here - if you feel adventurous you could give this a shot:
rewinding a brushless motor

#6

Sure, there you go. 25mm

IMG_20200214_193745
IMG_20200214_1937452610×4640 2.71 MB

I wont put that motor back together :wink: it will be doomed to sit on my desk in disgrace for eternity.

I was actually thinking of rewinding too. Never done it and would like to try. But first things first. Need to get on the street again asap :slight_smile:

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#7

2,5 cm. thats not a lot
now im even more curious how mine measure out :thinking:

ive never done it before either, but that instruction looks somewhat ok to follow, and you can allways ask around here for help if you get stuck

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#8

One week to go and I am done with exams. Gives me 8 full weeks of spare time. I think I just squeeze it between fixing my board and finishing my tankish couch (or couchish tank) :relieved:

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#9

Pot that portion of the stator/windings :wink:

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