Phase Rotation

Category: science

The chronological sequence in which the voltage waves of a three-phase system reach their peak values.

Phase rotation dictates the directional spin of industrial electric motors. If a three-phase system is wired out of sequence (e.g., A-C-B instead of A-B-C), an industrial air chiller pump or conveyor line will instantly spin backward when energized, risking catastrophic mechanical failure.

Common Examples

• The technician connected a digital phase rotation meter to the new machine disconnect to verify correct clockwise rotation before startup.
• Swapping any two hot legs inside a three-phase distribution cabinet will instantly reverse the downstream system phase rotation balance.