Power Factor

What is Power Factor?
To understand power factor, visualize a horse pulling a railroad car down a railroad track.
Because the railroad ties are uneven, the horse must pull the car from the side of the track. The horse is pulling the railroad car at an angle to the direction of the car’s travel. The power required to move the car down the track is the working (real) power. The effort of the horse is the total (apparent) power. Because of the angle of the horse’s pull, not all of the horse’s effort is used to move the car down the track. The car will not move sideways; therefore, the sideways pull of the horse is wasted effort or nonworking (reactive) power.

The angle of the horse’s pull is related to power factor, which is defined as the ratio of real (working) power to apparent (total) power. If the horse is led closer to the center of the track, the angle of side pull decreases and the real power approaches the value of the apparent power. Therefore, the ratio of real power to apparent power (the power factor) approaches 1. As the power factor approaches 1, the reactive (nonworking) power approaches 0.

EQUATION:     Power Factor = Real Power / Apparent Power

EXAMPLE:     If Real Power           = 100kW
                   And Apparent Power = 142 kVA
                   Power Factor         = 100 / 142 = 0.70 or 70%

This indicates that only 70% of the current provided by the electrical utility is being used to produce useful work.

What is Power Factor Correction?
As illustrated above PF relates to power quality or efficiency in a power supply system. A PF below 0.9 is low and a PF of 1 (unity) is the optimum.

A major cause for low PF in industry and commerce can be traced to items of electrical equipment that may not be working to full rated capacity. Power Factor (PF) correction helps businesses maximise energy use by reducing waste.  High on the list of suspects are air conditioning compressor motors, machines running on idle mode and dated fluorescent lighting systems. This causes electrical inefficiencies to the incoming power supply system. A low factor can be improved by having a power factor correction unit installed which can improve the hidden running costs of motors and other inductive loads.

Supply Authorities recognise PFC as a well established method of reducing electricity costs and other harmful effects which can usually be corrected with the installation of capacitor banks connected across the incoming power supply mains and/or other sections of the power system.

Energy Savings Strategies

Using power analysis, logging and recording instruments our staff can survey the PF of your power system, provide a brief report and recommend a suitable power factor correction system, especially designed for your installation.
Minimise waste in electricity consumption
Reduce KVA power demand and associated electricity costs
Prevent additional Supply Authority penalty charges where applicable
Recover lost cable capacity enabling the installation of additional equipment
Reduce heat losses in cables and electrical equipment thus increasing life span
Reduce demand on power stations thus reducing Green House Gases

What are the benefits of improving low PF in your industrial or commercial premises:

Further information can be found with our supplier partner links below:

Power Factor Correction and Harmonic Filtering
Power Factor Correction Solutions
NHP - Power Factor

What can Velocity Electrical do for you?

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