What does a split-phase motor use to develop starting torque?

A split-phase motor develops starting torque primarily through the use of inductance in different windings that are energized at different times. In a split-phase motor, two coils are wound on the stator: the main winding and the auxiliary winding. The auxiliary winding is connected in such a way that it creates a phase shift between the current in the two windings. This phase difference causes the motor to produce a rotating magnetic field, which is essential for starting the motor.

The use of the auxiliary winding in conjunction with the main winding creates electrical characteristics associated with both inductance and resistance, which are used to optimize the starting torque. While capacitors can indeed be involved in certain motor types (like capacitor-start motors), the split-phase motor primarily relies on the differences in inductive reactance between the two windings to achieve the desired torque.

The choice involving capacitive reactance, inductive resistance, or solely inductance would not accurately describe the fundamental operation of a split-phase motor since it mainly exploits the characteristics of inductance and phase shifting to initiate motion.