Dingfeng Capacitor--The function of fan capacitors.
Issue Time:2018-05-09

The function of fan capacitors

The capacitor is used to generate phase difference between the current generated by the two coil windings of the single-phase motor, and thus the motor is rotated in one direction.Otherwise, the two winding current phases are the same, and the motor cannot determine which direction to rotate.

Capacitor is using its own characteristics, on the other side of capacitor voltage mutation, but current can also be mutation, and just at the instant of the mutation, lenz's law make the motor coil produces phase is 90 degrees of phase (that is, the motor starting current).

Fan capacitors are mainly used to drive the phase displacement of the main auxiliary winding of the electric fan to 90 degrees, forming a rotating magnetic field so that the fan can be turned. In a simple way, it is the starting function.


The structure of electric fan is generally composed of motor, wind blade, timer, rectifier, capacitor and other accessories. Fan capacitor for non-polar capacitor commonly, generally greater than   250 v voltage, capacity of about 5uf, fans will not be able to start properly without it, because most of the fan is single phase, and directly using a single-phase electric cannot produce enough to start the magnetic field, also won't be able to maintain a good work.So this kind of motor usually has two winding, main winding and auxiliary winding. The main winding is directly incorporated into the circuit, and the auxiliary winding is connected to the circuit through the capacitor, so that the auxiliary winding has an angle difference. And capacitor acts as a phase shift, let a deviation in phase, it is equivalent to the two different phase and phase, the rotor can be started up, and then the main winding magnetic field make it work, continue to promote the auxiliary winding, so that they don't stop because of the external force.