We’ve created a quick reference guide for common electrical power equations related to fractional horsepower motors.
Power – AC Circuits
Efficiency = (746 x Output HP) / Input Watts
Three-Phase Kilowatts = (Volts x Amperes x Power Factor x 1.732) / 1000
Three-Phase Volt-Amperes = Volts x Amperes x 1.732
Three-Phase Amperes = (746 x HP) / (1.732 x Volts x Efficiency x Power Factor)
Three-Phase Power Factor = Input Watts / (Volts x Amperes x Power Factor x 1.732)
Three-Phase HP = (Volts x Amperes x Efficiency x Power Factor x 1.732) / 746
Single-Phase Kilowatts = (Volts x Amperes x Power Factor) / 1000
Single-Phase Amperes = (746 x HP) / (Volts x Efficiency x Power Factor)
Single-Phase Efficiency = (746 x HP) / (Volts x Amperes x Power Factor)
Single-Phase Power Factor = Input Watts / (Volts x Amperes)
Single-Phase HP = (Volts x Amperes x Efficiency x Power Factor) / 746
Power – DC Circuits
Watts = Volts x Amperes
Amperes = Watts / Volts
Horsepower = (Volts x Amperes x Efficiency) / 746
Speed – AC Machinery
Synchronous RPM = (Hertz x 120) / Poles
Percent Slip = ((Synchronous RPM – Full Load RPM) / Synchronous RPM) x 100
