Small drives that control three-phase motors can be supplied with which power configurations?

Small drives that control three-phase motors can be supplied with which power configurations?

• A. Either 3Ø or 1Ø
• B. 3Ø
• C. 1Ø
• D. Neither 3Ø nor 1Ø

Answer: (A)

Small drives that control three-phase motors are designed to accept either 3-phase or single-phase input. These drives, such as VFDs, have an input stage that rectifies the AC to a DC link and then inverts it back to three‑phase AC for the motor. When powered from a single-phase supply, the drive can still produce a three-phase output, but it’s typically derated, meaning it may deliver less horsepower than with a full 3-phase input. With a proper 3-phase supply, the drive can deliver its full rated output. So the flexible configuration is that these drives can be fed by either three-phase or single-phase power.

Small drives that control three-phase motors are designed to accept either 3-phase or single-phase input. These drives, such as VFDs, have an input stage that rectifies the AC to a DC link and then inverts it back to three‑phase AC for the motor. When powered from a single-phase supply, the drive can still produce a three-phase output, but it’s typically derated, meaning it may deliver less horsepower than with a full 3-phase input. With a proper 3-phase supply, the drive can deliver its full rated output. So the flexible configuration is that these drives can be fed by either three-phase or single-phase power.