Lots of electric motors these days use a bi-metal thermal overload switch in them, When heated the two metals expand at different rates, and this breaks the circuit when things become too hot. It is possible that there is a build-up of debris in the motor housing and particilarly near this switch, preventing things from breathing and staying cool. It is also possible that the switch has become weak, and releases too quickly. If it were mine, I'd try cleaning things up if I could before anything else.
Good luck,
Jeff
Good luck,
Jeff
