Saving energy by using adjustable speed drives

An adjustable speed drive often uses less energy than an alternative fixed speed mode of operation. Fans and pumps are the most common energy saving applications. When a fan is driven by a fixed speed motor, the airflow may sometimes be higher than it needs to be. Airflow can be regulated by using a damper to restrict the flow, but it is more efficient to regulate the airflow by regulating the speed of the motor. It follows from the affinity laws that reducing fan speed to 50% results in a power consumption drop to 12.1%