Formulas for Determining Amperes, Horsepower, Kilowatts, and KVA (KilovoltAmperes)
To Find  Direct Current  Single Phase  Three Phase 
Amperes when horsepower is known 
HP x 746 E x % EFF 
HP x 746 E x % EFF x PF 
HP x 746 1.73 x E x % EFF x PF 
Amperes when kilowatts is known 
KW x 1000 E 
KW x 1000 E x PF 
KW x 1000 1.73 x E x PF 
Amperes when KVA known 
KVA x 1000 E 
KVA x 1000 1.73 x E 

Kilowatts  I x E 1000 
I x E x PF 1000 
I x E x 1.73 x PF 1000 
KVA (Kilovolt – Amperes)  I x E 1000 
I x E x 1.73 1000 

Horsepower  E x I x %EFF 746 
E x I x %EFF 746 
E x I x %EFFx PF x 1.73 746 
% EFF = Percent Efficiency
OHM’S LAW
For Direct or Single Phase NonInductive Alternating Current.
Let:
I = Ampere Unit of current strength or rate of flow.
E = Volt Unit of electromotive force or electric pressure.
R = Ohm Unit of resistance to flow of current.
W = Watt Unit of power.