The motorís capacity to perform a physical task is commonly measured in horsepower (hp) and
kilowatts (kW). 1 hp is equivalent to 0.746 kW.
You can cut energy use significantly simply by reducing the speed of an HVAC fan. The energy consumption of fans and pumps varies according to the speed raised to the third power, so small changes in speed can make big changes in energy consumption.
Motor part-loads may be estimated through using input power, amperage, or speed measurements.
Efficient motors tend to operate at a slightly higher full-load speed than standard motors (usually by about 5-10 rpm for 1800 rpm motors.
Maximum efficiency is usually near 75% of rated load.
Thus, a 10-horsepower (hp) motor has an acceptable load range of 5 to 10 hp; peak efficiency is at 7.5 hp.