Power quality is critical to efficient operation of equipment. One contributing element to power quality is power factor.

Power Factor Correction (PFC) aims to improve power factor and hence power quality, utilising capacitors to offset usually inductive loads, for example motors. PFC systems increase the efficiency of power supply, delivering immediate cost savings on electricity.

When is Power Factor Correction right for you? Are you experiencing…

  1. Motor failure
  2. Electrical or electronic equipment failure
  3. Overheating of transformers, switchgear and cabling
  4. Nuisance tripping of circuit breakers or fuses
  5. Unstable equipment operation
  6. High energy usage and costs

How does Power Factor Correction work?

Power Factor is a measure of how effectively incoming power is used in your electrical system and is defined as the ratio of Real to Apparent (total) power where:

  • Real Power is the power that actually powers the equipment and performs useful, productive work.
  • Reactive Power is required by some equipment (eg. transformers, motors and relays) to produce a magnetic field for operation; however it does not perform any real work.
  • Apparent Power is the vector sum of Real and Reactive Power and corresponds to the total power required to produce the equivalent amount of real power for the load.


Power Factor Correction may be required where a system has a power factor of less than 90% (or 0.9). A poor power factor can contribute to equipment instability and failure, as well as significantly higher than necessary energy costs since it means that more current is required to perform the same amount of work. By optimising and improving the power factor, power quality is improved, reducing the load on the electricity distribution system.

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PFC equipment achieves a decrease in the total amount of electrical demand by using a bank of capacitors to offset an inductive load (or reactors if the load is capacitive).

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What we offer

Captech offer a range of products and services to ensure assess and improve power factor.


Our Power Factor Correction equipment maintenance includes checking that the system is operating at optimum performance levels. We check the following:

  • Electricity load reduction
  • Voltage levels
  • Harmonic content
  • Detailed equipment condition
  • Full functional operation

This level of maintenance is recommended by manufacturers to be undertaken every 6 months, or as required.

A comprehensive report is supplied on completion detailing the works carried out. It includes specific recommendations for consideration.


Captech offer a range of low, medium and high voltage PFC solutions.

1. OPTIVAR – Solid State Switched capacitor banks provide faster operating times by using thyristors instead of contactors for switching. The OPTIVAR system is specifically designed for applications where very fast load fluctuations exist and conventional PFC systems response times are unsuitable. The very high speed switching operation is designed for dynamic power factor compensation.

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