To change the rotation direction of a three-phase motor, you must change the:

• A. Voltage
• B. Frequency
• C. Current
• D. Phasing

Answer: (D)

Rotation direction in a three-phase motor is set by the sequence of the supplied voltages. The three windings create a rotating magnetic field, and the direction of that field follows the order of the phases. If you swap any two of the three supply lines, the phase sequence reverses, the rotating field rotates the other way, and the motor spins in the opposite direction. Voltage and frequency affect speed and torque but not which way the field rotates. Current reflects load and torque but doesn’t determine direction by itself. So changing the phasing—the phase sequence of the supply—reverses the motor’s rotation.