Damage Neo 550 by misswiring connection to SparkMAX?

Technical
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1

One of the students connected the 3 power wires that go from a SparkMAX to a Neo 550 in random order. The motor did not move when they tried to run it. The students then removed the current limit setting in the SparkMAX and again tried to run the Neo 550 with no motion. They then called me for help and I noticed the messed up wiring between the Neo 550 and the SparkMAX. Once the wiring was fixed, they again tried to run the motor and this time it worked but it smoked.

So the question is, did the wrong wiring cause the motor to later smoke when it was correctly wired or was there some other issue?

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2

I do not know the exact cause, but I also had some Neo 550s smoked on me when they were connected correctly.

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3

We did that to a neo a few years ago. It instantly smoked and did not work after.

4

most brushless motors (i would assume including the 550) can have their 3 power wires connected in any order, and swapping any pair will just change the direction it spins. I doubt thats why it smoked.
My only guess is there was already something wrong with the motor that caused it to smoke.

5

We connected one wrong last year and it did not go well. Even if it would have just spun the wrong direction if open loop, the fact that there is feedback to the controller makes an mis-wiring potentially worse.

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6

Change the NEO and SparkMAX out, they both could be dead and if the SparkMAX isn’t then it could start to kill connected NEOs if it shorted on the sensor port

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7

Yes, if the sensor wires (in the plug-in connector with the very small wires) are out of phase with the large wires for the motor windings, the SPARK MAX can run full power to a phase without turning the motor. This is about the same as a stall condition and can smoke the windings.

If you have a 3-phase AC motor with no sensors or controller, switching the wires around might not do any harm, but that doesn’t apply here.

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8

i see, thanks for clarifying for me. learn something every day

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10

If the Neo 550 was going to get destroyed I would expect it to get destroyed immediately when powered on with the wrong connections. But smoke was not present when it was connected incorrectly. The smoke appeared once the wiring was fixed and it was powered on.

This is why it is a bit of a mystery to me.

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There are many ways to damage components. Even after doing electrical and electronic R&D for decades, I still encounter failure modes that I didn’t know could happen.

12

This is not true for sensored motors. The halls need to be 1:1 with the phase order, so commutation could smoke the motor if it’s miswired.

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