I recently upgraded one of the VESCs on my board to a Focbox, and ran one FOCBox and one Ollin VESC without problem for a few months. Then this happened (See Pictures Below).
It occurred when I ran over a thick crushed metal soup can in the road. The motor connected to this vesc locked up and threw me off. I tried turning the board off and just pushing it, but the motor was still locked up, making think the phase wires must have shorted. When I got home, I took apart the FocBox and saw this.
After disconnecting the motor from the focbox it spins fine, so I assume the phase wire was on the damaged focbox. Clearly, one of the fets is completely burned up, the PCB is damaged, and the DRV also looks very damaged.
Now I am trying to piece together what happened.
My theory is: The metal can hit the motor, and cause one of the magnets to break off, and short two of the copper windings in the motor, causing a large amount of current to continuously flow through the fet till it burned it, and the heat generated from that is what damaged the PCB and DRV chip.
Does that sound reasonable? Any other theories as to what may have happened?