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First, I need to declare my comments are not an expert opinion. Well, they are free of charge, anyways.

I suggest ensuring the measurement is reliable before proceeding with any further action. For general motors, a skin temperature of 100 C (212 F) is on the high side, without knowing further details. The winding temperature is expected to be higher, assuming the source of heat is not external. What is the ambient temperature during the time the motor was inspected?

If I were you, I'll refer to the datasheet to find out the winding insulation class and the max temperature recommended by the manufacturer. Part of the datasheet is the temp raise which could vary (40-60 C).

I'm not sure but I hope you can stop the motor as a precautionary action while you explore the case to avoid any damage.

Regards- Ali M. Al-Shurafa


This may be a good resource for your concerns about allowable temp and temp rise on motors

NEMA Insulation Classes (

From my experience with thermal images, it is just as important to understand the expected thermal "profile" (vs. the IR temperatures you are indicating).  Problem is....the image provided is not ideal. It seems to only show part of the motor.

It appears to show highest heating in the center part of the motor (stator) which is normal (vs. higher temps at the bearing locations).  I will "assume" you have taken into account estimated emissivity value?

Can you compare with similar motor?

Many other things we can get into but lets start simple


Jim P


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