Intertherm model P853A5 older style

Question

Intertherm model P853A5 older style AC unit fan will not start to rotate when thermostat control set to cool.I have a feeling that it might be the electric motor. I removed the screen and rotated the fan manually looking for a bearing problem but found the fan rotated smoothly without any problems.When I set the unit to cool I obsereved the fan motor trying to turn and then it stopped aplost like it could not handle the load of the fan.