Load calc for a DC motor with armature and field current

[jaraujo1]

I need to calculate KVA for a 100HP DC motor, with the following characteristics:
Armature:148 amps@500VDC
Field:2.38amps@300VDC
Base speed: 1750 RPM
I have not been able to find information on how the armature and field current/votage interact to figure out the KVA. Any information will be appreciated.

Juan

 

[coulter]

Normally one does not see the terms "kva" and "DC" in the same thought.

The short answer is pretty simplistic:
Armature is 148A X 500V = 74,000va = 74kva = 74kw
Field is 2.38A X 300V = 714va = .741kva = .741kw

And you likely already knew this.

So, I'm guessing you are more interested in the power required for the two power supplies you will have to have - one for the field and one for the armature.

For that, I would suggest checking the power supplies nameplate data for input power - or call the mfg. Thjere are no rules of thumb I know of.

carl

 

[rootboy]

Unless you are going to design your own DC drive, or unless you are installing this motor somewhere that still has 500VDC available, I would just select a 100hp drive from your favorite local supplier.

Or am I missing something? (not being sarcastic, just wondering).