Hi
I have to decide on a circuit breaker for a 22 KW, 3 phase 400V Air compressor.
Load current = P / (1.732 * V *PF) =22000 /(1.732*400*0.8)
= 39.69A
Therefore a 40A Type D CB is used.
These are my questions:
1. Do we have to include the PF if not given in the equipment datasheet for current calculation.
2. Is this the right way to find the size of MCB? i will also be including an overload relay. Is there anything else i need to lookout for?
Thank you in advance for your help.