Trouble With in-hub brushless motor

I finally got a good working brushless ESC to test out my motor with, but it does not quite seem to be working properly. In the video below you can see how the motor runs for a few seconds, and then the the ESC cuts out, and the motor stops. I can get the ESC to restart by turning the throttle all the way to 0, then turning it back up, but the ESC behaves the same as before, cutting out a few seconds after the motor starts up. I have a feeling it may be a phase wound backwards, but I want to get some second opinions before I start cutting up my motor.

Other than this, the motor seems to be running nicely (if only for a few seconds). Also note that the motor was designed for 30v (8s) operation, and is only being run on a 4s (15v) battery pack.

So if anyone has suggestions, please put them in the comments below.


2 Responses to “Trouble With in-hub brushless motor”

  1. Shane Says:

    Seems like the controller never gets out of start-up mode and times out. I guess the real question is why.

    You can check the phase polarity by sequentially applying DC voltage at low current to the 3P2 permutations. The rotor should move to six evenly-spaced positions.

    You can also check for soft shorts between phases, if you haven’t already. If it’s drawing a ton of current at low speed the controller might freak out. What’s the current rating on the controller?

  2. ChArLeS Says:

    Yup, I’m going to have to say “stuck in startup mode”. The first thing I would check too is phase-to-phase shorts. Do you have a current reading on it while it’s starting?

    Something else I would also do if the phases check out to be not shorted is actually run it at all 8S. Believe it or not, the motor might actually be generating too little (or not clean enough) BEMF for the controller to catch on. Running a higher voltage, especially if the motor is mild wound anyway, can improve it. I know that RazEr’s motor will not start on anything short of 5S.

    One more thing you can try is to give it a kick start using wound string or just a quick whip from your hand. Engage the throttle a little before, and see if it can catch on then.

    After all of this, if the motor STILL does not start, then it might be incorrect termination or winding direction.

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