elevation (above sea level) and motor service factor

[PEDRO ESCOVILLA]

one of our inspectors is studying a mike holt prep book for E2 Commercial inspectors test, and there is a comment regarding elevation and derating of motor service factor, can anyone shed some light on this? how does it apply, where and when would we use it. book say " "operation at a higher elevation may require derating a motors service factor. For instance, a motor with a 1.15 service factor at an elevation of 3300 feet or below is derated to a service factorof1.0 at 9000 ft unless the nameplate states that it was designed for a specific elevation". i never heard of this, don't doubt it, but help!plz thank you:jawdrop:

 

[Smart $]

Not a direct code issue. You can find plenty of info on the internet about it though...

http://www.google.com/search?source...,cf.osb&fp=7205d478fc85225b&biw=1083&bih=1131

 

[ActionDave]

Yep, motors have to be derated at altitude. I was told that thinner air doesn't dissipate heat as well.
We have had to do the same for transformers and generators.