Why does a single phase ac motor have to be a capacitor to start running?
Plus, the purpose of the capacitance is 90 degrees, the phase lag is not string of a phase winding capacitance, current phase Angle is zero, the other phase winding series capacitor after the phase Angle is 90 degrees, two phase winding to produce electric potential (torque).
A single phase ac motor is required to add capacitors for the official start of the operation: 1, the operation of the single-phase motor winding, can produce pulsating magnetic field, corresponding to the motor stator any electromagnetic fields, can only at this point including polarity changes direction and amplitude changes. That is, it cannot form a rotating magnetic field. In the stator, a starting winding is added, and the starting winding is 90 degrees in space with the main winding. Starting winding concatenated after a suitable capacitance, the equivalent circuit of the winding resistance becomes the inductance and capacitance in series circuit, as long as the capacitance value to meet current phase Angle leading voltage certain Angle, such as 30 degrees; At the same time, the current phase difference between the two windings is 90 degrees if the current of the perceptual running winding is 60 degrees, which is called the division principle. These two differ 90 degrees of electricity flow in time into the two differ 90 degrees of winding on the space, will be produced in the space (two-phase) rotating magnetic field, motor to spin the course
Because only the formation of a rotating magnetic field, a squirrel cage rotor spins, only increase the startup winding, but start winding must pass a capacitance phase shift make start winding current advanced main coil current 90 degrees, the formation of a rotating magnetic field motor to rotate (high power motor start will remove after start capacitance).
Single phase ac motor and capacitor are used to make use of the current advanced characteristic of the capacitor to build the rotating magnetic field and make the motor run.
