The auxiliary phase single-phase electric motor is the one with the broadest application. Its mechanical construction is the same as that of three-phase induction motors. Thus, in the stator there are two windings: one of thicker wire with a large number of turns (main or working winding), and one of thinner wire with few turns (auxiliary winding or starting winding).
The main winding stays on for the entire engine run time, but the auxiliary winding only operates during start. This winding is switched off when an automatic device is located, one part of the motor cover and another part of the rotor.
These motors are equipped with capacitor have a more vigorous (start) torque. When it is stationary, the springs cause the centrifugal masses to push the spool over the contacts, closing the starter winding circuit.
There are basically four types of single-phase induction motors with cage rotor (auxiliary phase), according to the auxiliary starting arrangement used: split-phase motor; Motor with capacitor start (capacitor-start); Motor with permanent capacitor (permanent-split); Motor with two capacitors (two-value capacitor).