Study on the Variation of Reactive Power and Power Factor According to the Pole Number of Induction Motor

Induction motor is a typical inductive load and a low power factor. This induction motor has low power factor even when starting, but it also has a low power factor when operating with light load or no load. Induction motors with the same capacity have different power factors depending on the number of poles. In general, when the number of poles is high, the power factor is low, and conversely, when the number of poles is low, the power factor is high. Even with the same number of poles, the power factor drops further when the magnitude of the load on the motor decreases. If the reactive power compensation capacitor installed to compensate for the dropped power factor is higher than the reactive power required for magnetization of the motor, self-excitation may occur. In this study, it was analyzed whether the reactive power of the capacitor installed for power factor correction could provide insufficient reactive power required for magnetization within the range of not causing self-excitation.