To reverse the rotation of a split-phase motor, which action is effective?

• A. Reversing the two connections to the starting relay
• B. Reversing the connections to the starting capacitor
• C. Interchanging the starting winding leads
• D. Reversing the plug in the electrical supply outlet

Answer: (C)

The direction of rotation in a split-phase motor is set by the relative phase of current in the main winding and the starting winding. The starting winding must be out of phase with the main winding to create a rotating magnetic field that defines the motor’s spin direction. Interchanging the leads of the starting winding swaps the current flow in that winding relative to the main winding, which reverses the phase relationship and makes the rotor turn the opposite way. The other actions don’t reliably change this phase relationship: altering the starting relay connections may not flip the winding’s polarity, reversing capacitor leads doesn’t change the non-polarized capacitor’s effect in a way that reverses direction, and reversing the plug in the outlet doesn’t affect the windings’ phase relationship.