Common Electrical Formulas

Formulas for Determining Amperes, Horsepower, Kilowatts, and KVA (Kilovolt-Amperes)

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 Non-Inductive 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.