I'm wondering why the steel laminations in a residential bathroom exhaust fan motor got so hot, so hot it slowed down and stoped. Within 5 minutes of running they got to 40 degF above ambient temperature. I compared to a similar motor and it rose to 20 degF in 5 minutes, acceptable, satisfactory.
I compared the resistance and inductive reactance of both motor stators that encircle the laminations. They were essentially the same, 26 ohms resistive, inductive too small to measure using a resistor in series and computing the reactive. I didn't examine the squirrel cage rotors, assuming no fault there. They both run at 3400 RPM per photo tachometer.
Any ideas? See photograph.
I compared the resistance and inductive reactance of both motor stators that encircle the laminations. They were essentially the same, 26 ohms resistive, inductive too small to measure using a resistor in series and computing the reactive. I didn't examine the squirrel cage rotors, assuming no fault there. They both run at 3400 RPM per photo tachometer.
Any ideas? See photograph.
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