Motor overheated, is it safe to use?

Hi everyone, I built a pretty reliable (twin) jet-board but just an hour ago while attempting to measure thrust in my pool, one of my SSS 56104 motors overheated and smoked from the back (barely visible amount of smoke), cooling sleeve/jacket was either leaking or clogged with debris, I had to pour a gallon of water over it to cool it down and after all it’s still running fine.
I opened up the case, bearings are fine, windings seem fine, no apparent rubbing on the stator, and it doesn’t smell bad, I’m afraid that the windings are now at higher risk of short.

What do you think I should do now?

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Hi Eden,

Do you have a LC meter? If so you can measure the “resistance” of each pole and see if its still okay.

If the motor is going to shorten, it might/will burn your ESC too!

I personally woud not trust it anymore.

Do you have any pictures of your jet-board? I would love to see it :slight_smile:


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I’ve burned a 56104 to the point of the windings turning black, and it still works fine to this day, although it has been retired. It was in a sealed pod so can’t comment on how much smoke it put out but I would imagine a fair bit!

I would keep using it like nothing happened.

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It’s a risk to use it, if there was smoke then winding varnish will at the minimum be more brittle so there’s a higher risk for shorts in the future

I’d do these decision steps:
Do an isolation test between the phase wires and the stator, screws and axle with a proper isolation tester like megger or fluke at higher voltage =>250V.

Do a kV test: measure each phase-phase wire combination voltage when motor is driven as a generator with a drill press or even cordless drill. Voltages out should be roughly the same at the same rpm.

If any of these tests are NOK, replace it.

If these are OK then depending on:
Is your esc a lot more expensive than your motor?
Is your motor within your budget to replace?

If both these are true then i’d anyway replace it. You can always rewind the motor as a winter project :slightly_smiling_face:


My 2 cents - fill with corosion x and plough on until she goes


thing is that most likely it will take the esc with it when it goes… but it depends on if you’re in the mood to do things right or to take a risk :grin:


That would only be measurable if the motor is not connected in star.