Power Analysis
Power Analysis
(OP)
A switchgear/MCC has 2 motors or pumps rated 28.26kW (3-phase) and 13.42KW (1-phase). How do I calculate for the total current in order to size the main circuit breaker or fuse in the main supply to the switchgear?






RE: Power Analysis
Assuming you are in USA or NEC world. If not refer to similar IEC code.
RE: Power Analysis
Basically use this formuala:
for 3 phase:
KVA Rating/(SQRT(3)*Voltage)=Current
For 1 Phase:
KVA/Voltage = Current
For you KVA = KW when using unity power factor. The single phase load is only going to increase the current draw in one phase of your 3phase supply. Add it to the 3-Phase current and size your breaker at about 20%-25% greater than this number.
RE: Power Analysis