If you have a system using a motor that serves a varying load, an Adjustable Speed Drive (ASD) may benefit you. Examples of such systems are fans that reduce flow for non-design conditions or pumps that use control valves to vary flow. ASDs tailor motor performance to match present conditions.

Advantages include:

• Energy savings
• Improved process flow
• Softer/easier motor starting
• Faster response than valves or dampers

Induction motors account for over 90 percent of the motor horsepower in use today. The frequency of the electrical power running it determines an induction motor’s speed. Sixty cycles per second will run a meter at full speed. An ASD reduces the frequency of the electrical power to the motor, reducing motor speed and saving energy in systems with a varying load.

An ASD varies the electrical frequency to the motor to regulate its speed. They reduce motor speed by converting the standard 60 cycles-per-second, alternating current (AC) electrical power to direct current (DC). The ASD then uses an inverter to convert the DC back to varying frequencies of AC power, which controls the motor speed.

Get more information by downloading our handout in PDF format. You can also learn more about our energy efficiency programs for your state: California | Oregon | Washington  | Wyoming.