Running electric motors in high ambient temps

[Hippo41]

I have a situation in which I am required to run small 3-phase motors (0.18KW; 0.37KW and 0.09KW) in an enclosed space at 90 celsius ambient temp.

I understand that the motor efficiency will decrease drastically. We have used Class F insulation motors in the past. The loads are light, and there are very infrequent starts/stops.

Can anyone offer comment on the expected reliability of motors in this environment?

Should we used forced cooling fans to get some airflow over the windings?
Should we specify Class H insulation?

Any advise welcome. Thanks!

Lester Milton
Telford, Shropshire, UK

 

[jbartos]

Suggestion: The H insulation will increase the life expectancy of motors. In some applications, it is possible to develop an external water-cooling system, essentially a water spray, if the motor housing permits is.

 

[Shortstub]

Motors used to drive fans of horizontally mounted fin-fan process heat exchangers, if mounted in the discharge air stream above the fin-fan coils, are in ambients that easily exceed 90 deg ambients.

Class H insulation is the choice all the time!

 

[busbar]

Also, lubricants may need review for the applicaton.

 

[dpc]

You are probably already aware that a standard motor will have to be severely derated for operation at this ambient. So you will need to oversize the motors or purchase motors nameplated for this ambient.

 

[Hippo41]

Thanks for the advice.

Lester Milton
Telford, Shropshire, UK