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Power Factor Correction Information

What is power factor correction?

Power factor correction units counter the reactive power generated by industrial electrical equipment.

Reactive power reduces the power factor of an electrical system.

A low power factor increases maximum demand and electricity costs.

Power Factor Correction Triangle - PQIS

Power factor correction units reduce electrical system losses, reactive power and maximum demand.

A power factor above 0.95 will increase system capacity, eliminate reactive charges, and reduce downtime. 

The power factor of a business supply can be checked on the electricity bill. If this is below 0.95 contact PQIS.

A low power factor is caused by inductive electrical load generating reactive power in an electrical system.

Inductive loads are applied to electrical systems by equipment used in all types of manufacturing, industrial and commercial processes. The inductive demand generates the reactive power measured on an electrical system.

The larger the reactive component of the power, without correction, the lower the power factor will be.

A low power factor will increase all the electrical values based around the current, increasing KW losses, heat in the system and electricity costs. A higher maximum demand is achieved and a higher agreed availability with the supplier is required.  In extreme cases the supplier may add 'reactive charges' to the electricity bill.

A system with a low power factor can also suffer faults and a reduced lifespan of motors and similar electrical equipment.

The solution to reduce reactive power in a low voltage electrical system is power factor correction equipment.

Power factor correction units are connected to a low voltage electrical system to react to the inductive loads by switching capacitor banks into circuit. The capacitance near eliminates the reactive power, reducing the current, maximum demand and KW usage of the supply.

The effect of a consistent power factor above 0.98 is reduced electricity costs, increased system capacity and an improved electrical environment for equipment.


Power factor correction equipment is usually installed or integrated with LV switchgear of a site. The annual maintenance of power factor correction equipment is necessary and recommended due to the natural deterioration of capacitor output. The deterioration of power factor correction units is not always obvious, particularly if without modern controllers which indicate equipment faults and low capacitor output.

Included in our annual maintenance service is a full report indicating capacitor output, component operation and equipment condition. With recommendations if applicable for improvement or repair.

If you require our power factor correction annual maintenance service, please complete the form on the contact page for free quotation

PQIS supply power factor correction units and services to companies looking to reduce their carbon footprint and electricity costs.

Businesses operating from new or established premises can benefit from PQIS solutions. Our engineers have worked with all types of industry to deliver power factor correction projects. 

Case studies of our work have been used to produce articles for and other publications which can be seen in the gallery below. 

For information regarding electrical efficiency and energy sustainability visit the 'The Power Quality Forum'.

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