Three-phase motors rely on a polyphase system for delivering continuous alternating current. Instead of the single power lead used in single-phase electrical systems, three-phase systems use three power leads. Each power lead is a phased 120 degrees apart from the other two leads, making them perfectly balanced. When each phase of the three-phase system is connected to its proper terminal in the three-phase motor, the motor runs forward, as it was designed. However, if so desired, the motor can be reversed by switching the order of the phases.
Things You'll Need
- Flathead screwdriver
Shut the breaker off that supplies power to the three-phase motor, then lock the breaker with a padlock to prevent the breaker from being turned on while you are working on the motor.
Unscrew and remove the cover of the motor using a flathead screwdriver, and determinate two of the three phases using a flathead screwdriver. It doesn’t matter which two phases are removed: T1, T2 or T3.
Swap the two phases and refasten them using a flathead screwdriver. Reinstall the cover.
Restore the power. The motor now runs in reverse because two of the phases have been swapped.