Amperes on the Electrical Contractor's Test
An Ampere is a measurement of current and it is represented by the letter A.
To calculate Amperes in Direct Current systems, use:
Amperes = Horsepower x 745.7 / Volts x Efficiency
I = HP x 745.7 / V x Eff
I = HP x 745.7 / V x Eff
or
Amperes = KW x 1000 / Volts
I = KW x 1000 / V
I = KW x 1000 / V
To calculate amperes on single-phase, use:
Amperes = Watts / Volts x Power factor
I = P / V x Pf
I = P / V x Pf
Amperes = Horsepower x 745.7 / Volts
I = HP x 745.7 / V
I = HP x 745.7 / V
or
Amperes Kilowatts x 1000 / Volts x Power factor
I = KW x 1000 / V x Pf
I = KW x 1000 / V x Pf
To find Amperes on three-phase, use:
Amperes = Watts / Volts x Power factor x 1.73
I = P / V x Pf x 1.73
I = P / V x Pf x 1.73
or
Amperes = Horsepower x 745.7 / Volts x Efficiency x Power factor x 1.73
I = HP x 745.7 / V x Efficiency x Pf x 1.73
I = HP x 745.7 / V x Efficiency x Pf x 1.73
or
Amperes = Kilowatts x 1000 / Volts x Power factor x 1.73
I = KW x 1000 / V x Pf x 1.73
I = KW x 1000 / V x Pf x 1.73
