Arducopter 3DR-B 880kv motor setup - one motor will not spin - Discussions

Hi there, my Arducopter/APM2 build has been coming along nicely and I think I am almost at the finish line. I am working on configuring my ESCs and am having a problem with one of my motors. I was able to configure my ESCs using automatic (I think) and when I plug in the LiPo all the ESCs beep rapidly for a while and then eventually, one by one, stop beeping and am able to arm the motors and make the rotors turn. If I arm while one ESC is still beeping that motor will not work, that was expected for me.

However, my issue is that even when all ESCs are silent and I have armed the motors (red light solid), I throttle up and all the motors move except for when. It makes the very anemic attempt at spinning and spins back and worth very little (maybe about 60 or 80 degrees in each direction) until what I assume is the ESC cutoff kicks in and it stops moving all together. All of this is happening while the other 3 motors are spinning fine and responding to throttle. When I stop the motors the one that isn't working is hot to the touch, much warmer than the other 3 motors that were actually spinning.

I know it isn't the binding issue with the 880kv's because I have widened my holes significantly before I ever even ran the motors.

Could it be that the motor is toasted? How could that have happened? Will configuring the ESCs individually help me? I can provide more info, or video of the partial spinning if need be. Somebody please help me, I'M SO CLOSE!!

Very simple, you are "single phasing" the bad motor. They are 3 phase motors, and the ESC senses via back emf where the motor is in rotation. One of the bullet connectors or wires to the motor is not making connection.The ESC attempts to run the motor, but senses the problem and shuts down. Again, this is a motor to ESC problem. We know 2 wires are good, it gets hot so there must be a path, but the third wire is broken.

Could be the wire in the motor, the bullet or at a rare case, the ESC, but being you upgraded the motors (that what it sounds like you did), then either the motor is bad or the bullet soldering job was bad. You can disconnect the wires and ohm out. They should all short to each other. If one is open, then that's the bad wire. In other words, there are 3 wires and any combination should be very low resistance (the motor is only a couple of turn of heavy wire).

Replies

Arunabha Bhattacharya September 9, 2012 at 10:02am

I'm having a similar issue. I setup my JDrones Arducopter in plus config with the APM2 board. Levelled it and started up in stabilize mode. I ran it through two batteries in stabilize mode. It was flying perfectly well, just ouling a bit to the left.Yesterday, I landed it after a flight, and when I tried powering up for takeoff, the left motor, ie, motor no 2, wouldn't spin up. The motor's working fine, I cross checked it with the other ESCs one by one. All the ESCs are fine, except that one. Do I have to replace my ESC now? Or can it be fixed?

What could be a plausible explanation for this sudden malfunction? There was no noise, nothing. I just landed, powered down, and when I tried taking off, it stopped working?
Calum Barnes August 11, 2012 at 8:51pm

Thank you! That would make sense, is there good way to figure out which one it is? Thanks for your help, I will look at the connectors now.
Vernon Barry August 11, 2012 at 8:35pm

Very simple, you are "single phasing" the bad motor. They are 3 phase motors, and the ESC senses via back emf where the motor is in rotation. One of the bullet connectors or wires to the motor is not making connection.The ESC attempts to run the motor, but senses the problem and shuts down. Again, this is a motor to ESC problem. We know 2 wires are good, it gets hot so there must be a path, but the third wire is broken.

Could be the wire in the motor, the bullet or at a rare case, the ESC, but being you upgraded the motors (that what it sounds like you did), then either the motor is bad or the bullet soldering job was bad. You can disconnect the wires and ohm out. They should all short to each other. If one is open, then that's the bad wire. In other words, there are 3 wires and any combination should be very low resistance (the motor is only a couple of turn of heavy wire).

This reply was deleted.