Field single-phase motor, instead of turning, just pulsates. Without rotor rotation occurs. Single-phase pulsed fields can be visualized in the form of two rotating fields, rotating at the same speed but in opposite directions. From this it follows that the rotor rotate in any direction almost synchronous speed, if it is given the initial impetus in any one direction or the other. The exact value of the initial velocity of rotation varies from different machines. Speed is above 15 percent synchronous speed, as a rule, is sufficient to cause the rotor speed up the nominal or running speed. In single-phase motor can be done with automatic start, if funds can be provided to give the effect of a magnetic field.
To get the split-phase motor is running, the start winding and start winding included in the electric motor stator. Fig. 7-9 shows the split phase motor with the end cap removed so that you can see on the trigger switch, and the Governor of the mechanism.
Engines of this type is difficult to use with air-conditioning and refrigeration equipment, as it has very low starting torque and not be able to run the compressor, because it presents the load on the engine immediately after starting.
This type of engine, however, very useful in the heating equipment (see Fig. 7-10).