How to Install Power Factor Controller

Power factor controllers is a kind of energy saving device in the electrical system. In this topic the author want to to discuss the basic procedure on how to install this device.
These are the steps:

 1. First determine the system voltage in order to know whether a PT or Potential Transformer is needed or not. Sometimes the system voltage such as in low voltage installations like 240 V or 480 V, a PT is not needed since there are PF controller in which its supply rating is at this level. For voltages higher than what was mentioned above, surely a PT is needed unless there are models that has a supply voltage that are compatible at that voltage level.

2. Determine the contact rating of the output relays and choose a magnetic contactor that has similar rating. This magnetic contactors will then control the activation and de-activation of the capacitors during operation.

3. Determine the maximum current of the system so that you can choose the correct ratio of the CT or current transformer. Once the correct rating of the CT has been determined clamp it to the supply mains of the system and connect the the CT to the terminals of the controller.

4. Connect a wire from the terminals of the output relay to the coil of the magnetic contactor. The number of steps of the capacitor controller determines the number of magnetic contactors to be installed.

5. Connect the wires from the supply of the system to the capacitors. A contactor is needed between the the capacitor and the supply of the system because the capacitor is to be energized and de-energized at any time.
6. Put the controller together with the other components in a panel with enough space and proper terminal markings. Read the manufacturers manual for the correct settings of the controller. In the setting you have to choose what is the power factor level you want to maintain. Remember that the controller will operate based on the input, therefore be sure to calculate and analyze the overall condition of the system before adjusting the settings.


  1. In power system networks, protection has to be designed such that protective relays isolate the faulted portion of the network, to prevent equipment damage, injury to operators and to ensure minimum system disruption enabling continuity of service to healthy portion of the network. If you want to more information about Relay Coordination, Please visit Relay Coordination