During these same conditions, I installed a fan motor for a homeowner and one hour later it quit. The homeowner was extremely angry with me and went back to check my work and found the motor wired correctly, but scorching hot. I replaced it with another motor and sat there for two hours to babysit the new motor. When I got to my shop that night I chopped the motor in half and as I suspected, the copper windings were not real copper! Talk to your technician and ask him about these and other high quality HVAC products made with YOU the homeowner in mind.