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Motor Breaker Sizing...

Motor Breaker Sizing...

Motor Breaker Sizing...

(OP)
Quick question.  Can I put a 40A Breaker on a 20HP rated Inverter driving a 20HP fan motor???  The Inverter is an Allen Bradely 1336 Plus 2 model.

Also, is RWU90 #10 wire OK?

RE: Motor Breaker Sizing...

What voltage?

(#10 AWG cannot be used with a 40A breaker)

RE: Motor Breaker Sizing...

(OP)
OK sorry.  you're right. #10 is only good for 30 A. I have 32.5 FLA. so I need #8 wire.  I will fuse at 30A (TD) and my breaker can be sized up to 60 A according to CE Code.  I think I figured it out... I asked question before trying to find answer myself.

RE: Motor Breaker Sizing...

Suggestion:
1. The circuit length is normally given a consideration for allowable voltage drop.
2. 32.5 FLA x 1.25 = 40.625 A. Therefore, the conductor next size is appropriate, e.g. #6AWG @60°C, 55A.
3. Check with the manufacturer for the recommended protection for the drive.

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