Which of the following best describes the split-phase motor?

• A. It uses the difference in winding inductance to offset the phases
• B. It uses the difference in supply voltages
• C. It uses a capacitor in parallel with the windings
• D. It runs only on DC

Answer: (A)

Split-phase motors create a rotating magnetic field by using two stator windings fed from the same AC supply, with the windings designed to have different impedances. That difference in winding inductance (and the resulting impedance) causes the currents in the two windings to be out of phase. When their magnetic fields combine, they rotate rather than align in a single direction, which starts the rotor moving. Once running, the starting winding is typically disconnected. This is why the key description is that the phase shift comes from the winding impedances, not from different voltages, capacitors, or DC operation.