给电机通电，它的线圈，会吸收电能，然后激发磁场，用来激发磁场的这部分功率，就是无功功率。显然电机不能没有磁场，也就是说电源线上的电流，部分是用来输送无功功率的。为了减轻线路的负担，若给电机并上电容，由于电容的无功正好和电感互补，电机所需的无功就由电容来承担，进而减小了电源线上的电流，这就是补偿的意义。

 What is the significance of capacitive RPC?

When a motor is energized, its coils absorb electrical energy and then generate a magnetic field. The portion of power used to generate the magnetic field is reactive power. Obviously, a motor cannot operate without a magnetic field, which means part of the current on the power line is used to transmit reactive power. To reduce the load on the line, if a capacitor is connected in parallel with the motor, the reactive power of the capacitor complements that of the inductor exactly. The reactive power required by the motor is then supplied by the capacitor, thereby reducing the current on the power line. This is the significance of compensation.