Flow of single-phase capacitor motor current does not produce a rotating magnetic field, need to take the capacitor is used to split phase, the purpose is to make the two in the winding current to produce nearly 90 ゜ phase difference, in order to produce a rotating magnetic field.
Two identical pulsed magnetic fields are formed in time and space, so that a rotating magnetic field is generated in the air gap between the stator and the rotor. Under the action of the rotating magnetic field, the induction current is generated in the motor rotor, and the interaction between the current and the rotating magnetic field generates the electromagnetic field torque, so that the motor rotates.
In order to make the capacitor motor rotate automatically, we can add a starting winding in the stator, the starting winding and the main winding are 90 degrees different in space, the starting winding should be connected with a suitable capacitor, so that the current and the main winding are approximately 90 degrees different in phase, that is, the so-called phase separation principle. Such TWO CURRENTS 90 DEGREES APART IN TIME FLOWING INTO TWO WINDINGS 90 DEGREES APART IN SPACE WILL GENERATE A ROTATING MAGNETIC FIELD IN SPACE. Under the action of the rotating magnetic field, the rotor can start automatically. After starting, when the speed rises to a certain point, the starting winding will be disconnected by means of a centrifugal switch or other automatic control device installed on the rotor, and only the main winding will work under normal operation. Therefore, the starting winding can be made to work in a short time mode. But there are many times, the starting winding is not disconnected, we call this motor capacitance electric, to change the steering of this motor, can be achieved by changing the position of capacitor series.
Capacitors are designed to generate rotating magnetic fields in a single phase of electricity. If no capacitance is this: the motor after electrify creates two same speed, steering instead of a rotating magnetic field, the two magnetic fields generated by the torque force is zero, so the rotor can rotate, but this is if add a force to it, you can rotate, the external force is clockwise turn clockwise, external force is anticlockwise turn counterclockwise.
Therefore, if you want to automatically turn, you need to add a capacitor. The capacitor is added to the starting winding. The difference is 90 degrees in space, which will generate an additional rotating magnetic field, which is equivalent to the external force. At this time, it will rotate. When the speed reaches a certain speed, the switch of the starting winding will be disconnected by centrifugal force, and then the main winding will act to rotate it.
