It sounds as though the motor is taking too much current. I would disconnect it from the load , slacken/remove any V belts. Try to spin the motor shaft by hand. It should be smooth in rotation, if it feels rough your bearings need to be oiled/replaced.. Try running the motor, if it still trips out then its the motor, if it runs OK, your linisher bearing/belt tension needs to adjusted. Of course that actual trip might have gone faulty and is tripping at too low a current. It would be good to run the motor of another circuit to check this out or measure the motor current.

If the motor has got holes in its case it is likely that dust has bunged up the works and it needs a strip down and clean. If you get this far then the state of the copper windings can be inspected as it is possible that if the windings have got hot enough the varnish insulation might have been damaged causing a short circuit turn and further overheating. The smell of the innards will tell you this immediately you open the casing.

Frank

Exactly these symptoms, occurred with my linisher and not having much of a clue about motors it baffled me for a while. I then carried out a partial dismantling to try and identify any obvious fault and found that a certain amount of metallic dust had accumulated in and around the motor. Five minutes with the hoover and it was working OK and still is.

Mick