Reactive power capacitors compensation principle: In the AC circuit, the load from the power supply of electric power, there are two; one is active, one is reactive power.

    Active power is maintained electrical equipment required for the normal operation of electric power, that is, converting electrical energy into other forms of energy (mechanical energy, light, heat) of electrical power.

    Reactive power is relatively abstract, it is used in a switched circuit of electric and magnetic fields, magnetic fields and used to establish and maintain the electrical power in electrical equipment. It is not external work, but transformed into other forms of energy. Where there solenoid electrical equipment, to create a magnetic field, it must consume reactive power. Reactive power is by no means useless power, it has proved very useful. Motor needs to establish and maintain a rotating magnetic field, the rotor is rotated so as to drive the mechanical movement, the motor rotor magnetic field is achieved by reactive power from the power establishment. Transformers also require reactive power, in order to make the primary winding of the transformer produces a magnetic field, a voltage is induced in the secondary winding. Therefore, no reactive power, the motor does not rotate, the transformer can not swing, AC contactor does not energize.