Single-phase induction motors:

At first glance one might assume that it would be impossible for a spinner, which would only create a single phase supply. With the help of an auxiliary stator windings displaced by the main winding, it is possible, however, a second Magnetomotive (MMF) in the auxiliary winding out of phase with the MMF in the main winding, and that is generating sufficient to create the rotating field.

Capacitor-Run Motors:

The necessary phase shift between the main and auxiliary windings can be provided by a high value in series with the auxiliary winding. These motors are often used in household washing machines, refrigerators and shower pumps and can be easily identified by the large electrolytic capacitor, strapped to the motor body. As an alternative to using an external capacitor, the split-step method uses a high resistance auxiliary winding. The difference in the impedance of the two windings is sufficient to create the necessary phase shift between the currents in the two windings.

Shaded pole motors:

The shaded pole motor uses a different, more crude, method of induction of a second stator MMF, in phase with the main MMF in order to create the desired rotating field of a single-phase AC supply. A shorted turn, thick copper, as mentioned, the shading ring is in a slot in the pole-mounted units. Some of the magnetic flux produced by main winding leads to a current in the shading ring, which delayed its own weak stream, and opposes the main flow through the ring, so that the resulting flux through the ring is out of phase with the major river created. Thus, there is a phase difference between one side of the bar and the others. Although inefficient, this method is even sufficient, a spinner.

Features:

Single-phase induction motors are less efficient than multi-phase machines have been developed mainly for domestic use, as most apartments are furnished with single phase electricity. No control of the speed.

Applications:

All types of household appliances and light industrial applications.

Synchronous AC Motors:

The synchronous motor is similar to the induction motor, that means a step machine, is generated in the stator is a spinner, but the rotor is supplied by either permanent magnets or electromagnets built DC-energized via slip rings.

Torque:

The torque depends on the attraction of the rotor magnets to the rotating magnetic poles and not on the relative motion between the windings in the rotor and the rotating magnetic field. Therefore, it can lock rotating on the field. See the Alternative Motor Action. Unlike able-cage induction motors, synchronous motors run and produce torque at synchronous speed. They are hard to be launched at system frequency as the rotating field is too fast, so they need to start at a lower frequency, or they need auxiliary windings or bring a rudimentary cage calmly to the rotor up to synchronous speed. As the motor approaches synchronous speed, it will suddenly snap-in to synchronize.

Pull In Torque:

To achieve the synchronization of the engine torque will be greater than the load torque. The torque developed when the motor is at synchronous speed as the train torque locks. If the load is greater than the train engine torque will not reach synchronous speed.

Pull Out Torque:

As the engine load is increased, the engine torque and the angle of rotation will also increase. However, if the torque angle exceeds 90 degrees, the torque begins to fall, and the engine will lose synchronization and finally stop. The pull out torque is usually 1.5 times the constant torque.

Features:

Synchronism.

Applications:

Fixed-speed applications such as clocks and timers