Winding Temp

[Feg]

Hi Guys

We have a 250kw 1465 rpm 400v 3ph IP55 motor working on a pump application in an amb of 28 deg indoors. This motor has rtd's fitted and is giving a reading of 80 deg C. Can anyone tell me if this is ok at that temp and how can this be worked out.

The motors are rated class F

Thanks

 

[Clyde38]

Should be fine.

Go to

http://www.motorsanddrives.com/cowern/motorterms4.html

for information.

 

[Skogsgurra]

Sounds perfectly normal.

Class F can be taken a lot higher. From top of head, I think it is 155 C maximum (hot spot). But not recommended. Your bearings tend to lose grease if motor temperature gets too high. But windings can take it.

I would not start bothering before around 110 C - and that would be for bearings mostly.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[aolalde]

I agree with the posts above.
Total temperature of 80 °C, at 28 °C ambient means 52 °C Temperature Rise, due to the losses generated under motor load.
Modern motors have around 80°C temperature rise over 40°C ambient for a total operating temperature of 120°C, with insulation class 130°C (B) or 155 °C (F).
Your motor is working very cool, may be the load is too low.

 

[Skogsgurra]

Yes, probably.

Gunnar Englund

http://www.gke.org

--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...