What is the role of a VFD in pumping systems within BAS?

• A. They control pump speed by adjusting motor frequency.
• B. They generate heat.
• C. They measure energy usage.
• D. They store data.

Answer: (A)

A VFD in pumping systems regulates how fast the pump runs by changing the electrical frequency supplied to the motor. This lets the building automation system dial the pump output to match demand, instead of always running at full speed. Because pump power for many pumps varies roughly with the cube of speed, small reductions in speed yield large energy savings and reduce wear from starts and stops. A VFD also provides smooth acceleration and deceleration, which helps maintain stable pressure and reduce noise. It isn’t meant to generate heat, measure energy, or store data—those tasks are handled by other BAS devices and meters.