I'm asking this because a friend of mine had it happen. He was using an electric (corded) drill to mix some thinset material for ceramic tile. He stopped the drill and set it down on the floor. Moments later it burst into flames. Luckily he was there, and he unplugged it and held it by the cord and tossed it out the window into snow, which made out the flames.
I have seen several power tools begin smoking, some that shot sparks out of the vents by the brushes, and most that died, simply stopped working. But I have never seen any power tools burst into flames.
But this is a good friend and I know he is not making this up. He said it scared the crap out of him, but he reacted quickly and took care of the problem. He also said the house circuit breaker did not trip.
I almost wonder what could ignite inside of a drill motor? I know the wire windings are coated with a shellac or similar coating, which could burn, but everything else is metal which dont burn. He said the flames were shooting out of the vent holes in the plastic case and were starting to melt the plastic, but the case was not yet burning, when it hit the snow outside.
Has anyone else ever had this happen?