Effects of heat on a motors life 1

[Inky29]

I'm trying to find some information on the effects of heat on a motors longevity. I want to say that someone told me once that for every 10% you lower the motor temperature you can extend the life of the motor by about 10 years. Has anyone else heard that before or am I totally off base here.

 

[jOmega]

See:

http://www.ecmweb.com/ar/electric_hot_issue_motor/

"As a general rule of thumb, insulation life doubles for each 10

°

of unused insulation temperature capability. For example, if you design a motor to have a total temperature of 110

°

C (including ambient, rise, and hot spot allowance), but build it with a Class B (130

°

C) system, an unused capacity of 20

°

C exists. This extra margin raises the expected motor insulation life from 20,000 hr to 80,000 hr."


"Similarly, if a motor's load is less than full capacity, its temperature rise will be lower. This automatically lowers the hot spot temperature and extends motor life. If the motor operates in a lower than 40

°

C ambient temperature, its life will be longer. The degree rule applies to motors operating at {sic: or} above rated temperature; insulation life drops by half for each 10

°

C of overtemperature."


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[Inky29]

Thanks! I knew it was something about 10 but I couldn't remember if it was degrees or percent of the motors running temperature. This has helped me out tremendously.

 

[jbartos]

Suggestion: Visit

http://www.silicavalley.com/archives/Reliability.pdf

for the mathematical relationships often referred to Arhenius relations, curves, aging, etc.