In motor starting terminology, what electrical effect does the starting capacitor produce between windings?

• A. Phase shift
• B. Voltage boost
• C. Current limit
• D. Heat generation

Answer: (A)

The starting capacitor’s role is to create a phase shift between the currents in the main (run) winding and the auxiliary (start) winding. By making the start winding current lag or lead by about 90 degrees relative to the run winding, a rotating magnetic field is produced, which generates the starting torque that gets the motor turning. After startup, the capacitor is removed from the circuit so it’s not continuously energized. This isn’t about boosting voltage, limiting current, or heating; the key effect is establishing the proper phase relationship to create a rotating field.