FP burning out

[Max Lobovsky]

Today we had an FP burn out on us when using it as the winch in our forklift. I'm trying to figure out why it happened and i was wondering if anyone had experience with them burning. Potential causes in this case were

a side-loaded output axle
sawdust, aluminum shavings, or other particles in the motor
stalling

Because the motor has a 70 amp stall current and we had the 40 amp breaker on and because it stalled at most for 2 or 3 seconds before releasing serious smoke, I'm tending to think something got inside. If anyone has any idea, that would be a great help, thanks.