One day at a time, the insulation on the wires to the motor got softer and oilier.

Over the years it broke down gradually until one day, the voltage began shorting to the motor housing.

Slowly and imperciptably at first perhaps, but finally and suddenly,

the motor overheated. The fan belt was not well aligned with the motor shaft either, adding heat and wear to the system.

A new motor purchased at Grainger was swapped in and realigned with squirrel cage fan.