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.