When a motor has been overloaded it will display characteristics that enable a repair facility to inform the customer of the problem.  When a motor has been overloaded it is extremely important that the customer be informed because it would normally mean there is a fault in the driven equipment.  If that fault is not repaired then the repaired or replacement motor will also burn out. 

When a motor is overloaded it will experience thermal and dielectric aging.  The defect in the driven equipment will cause high amperage in the winding and the high amperage will cause excessive heat. 

When the winding is examined for cause of failure it will show that every coil of every phase has been overheated leading to multiple turn to turn shorts.  The motors cooling system is designed to maintain a temperature range at a given amperage.  During an overload condition the cooling system cannot maintain that temperature.