Which statement describes the typical use of Variable Frequency Drive motors in building systems?

Which statement describes the typical use of Variable Frequency Drive motors in building systems?

• A. Are typically used on most high efficiency commercial AC systems
• B. Are rarely used in commercial settings
• C. Only apply to DC systems
• D. Do not influence energy efficiency

Answer: (A)

Variable Frequency Drives let you control the speed of an AC motor by adjusting the electrical frequency, so fans, pumps, and similar equipment run only as fast as needed. In commercial buildings, this speed control is widely used in high‑efficiency systems because it delivers meaningful energy savings and better performance. When you slow a fan or pump, the energy it uses drops substantially—power for these loads scales roughly with speed cubed—so even a small reduction in speed can cut electricity use a lot. VFDs also provide smoother operation, reduce inrush and wear, and improve control of airflow or system pressure. They aren’t limited to DC systems, and they do influence energy efficiency.

Variable Frequency Drives let you control the speed of an AC motor by adjusting the electrical frequency, so fans, pumps, and similar equipment run only as fast as needed. In commercial buildings, this speed control is widely used in high‑efficiency systems because it delivers meaningful energy savings and better performance. When you slow a fan or pump, the energy it uses drops substantially—power for these loads scales roughly with speed cubed—so even a small reduction in speed can cut electricity use a lot. VFDs also provide smoother operation, reduce inrush and wear, and improve control of airflow or system pressure. They aren’t limited to DC systems, and they do influence energy efficiency.