The operation of the single-phase motor offers some peculiarities due to its shape, because instead of a concentrated coil, the winding is arranged in grooves to produce a quasi-sinusoidal electromagnetic force. https://www.mrosupply.com/gears-gear-rack/change-gears/2277366_ncs1284_browning/ A single-phase winding will produce identical electromagnetic forces, forward and backward. This produced force causes that the motor does not present / display a conjugate of departure, due to the mutual cancellation of her. When coupled with the main winding current, the current in the auxiliary winding enables a rotating magnetic field to be produced in the stator.
Upon starting the engine, a switch shuts off the auxiliary winding and in these cases the starting torque is still slowed down. As a solution, to create a sufficient torque for certain applications, a series capacitor is used together with the auxiliary winding. The single-phase motor has no rotating field, but rather a pulsating magnetic field. For startup, the motor needs auxiliary means such as auxiliary windings and the use of a capacitor to give rise to a false second phase, allowing the origin of a rotating field and conjugate sufficient to remove it from the rest.