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Power factor is a measure of how effectively your equipment converts electric current to useful power output, such as heat, light or mechanical motion. Businesses with equipment that cause a low power factor in their alternating current (AC) electricity system are paying for more electricity than they are actually using.
A system of capacitor banks can be installed to correct the wasted power factor, ensuring a building uses all the electricity it pays for.
How it works
Power factor loss is an issue for devices such as motors – torque is created in motors by creating an out-of-phase condition between the electrical and magnetic fields. This is called field excitation and results in inductive, or lagging, power within the electrical circuit. Optimal loads exhibit a power factor of “1” because they use a minimum of current for each unit of power output. Inductive loads, however, require a larger flow of current for a given voltage. In other words, the apparent power use for inductive loads is greater than the real power used. Since energy losses in distribution lines increase with increasing current flow, utility suppliers measure the apparent power used by their customers. This results in many businesses paying 10% to 30% for electricity above what they actually used.
There are many sources of inductive loads – lighting served by ballasts (fluorescent, metal halide, etc.), welding machines, and motors are the major sources. Correcting this lagging power is usually served by adding capacitors in parallel with these loads. Capacitors store power and produce a leading power factor by adding current in the opposite direction of the inductive load; thereby effectively cancelling the current imbalance.
In actual operation, however, varying loads can induce instability in the voltage supply called harmonics. These can be caused by adjustable speed drives or starting and stopping loads which make up the normal operation in any business. Harmonics left unchecked can result in premature equipment failure, uncomfortable “flicker” in the lighting, or unreliable surge protection for delicate and expensive computer and office equipment. A properly corrected power factor system always includes a harmonic sweep and the addition of line filters if necessary.
Benefits
Power Factor Correction
What it isPower factor is a measure of how effectively your equipment converts electric current to useful power output, such as heat, light or mechanical motion. Businesses with equipment that cause a low power factor in their alternating current (AC) electricity system are paying for more electricity than they are actually using.
A system of capacitor banks can be installed to correct the wasted power factor, ensuring a building uses all the electricity it pays for.
How it works
Power factor loss is an issue for devices such as motors – torque is created in motors by creating an out-of-phase condition between the electrical and magnetic fields. This is called field excitation and results in inductive, or lagging, power within the electrical circuit. Optimal loads exhibit a power factor of “1” because they use a minimum of current for each unit of power output. Inductive loads, however, require a larger flow of current for a given voltage. In other words, the apparent power use for inductive loads is greater than the real power used. Since energy losses in distribution lines increase with increasing current flow, utility suppliers measure the apparent power used by their customers. This results in many businesses paying 10% to 30% for electricity above what they actually used.
There are many sources of inductive loads – lighting served by ballasts (fluorescent, metal halide, etc.), welding machines, and motors are the major sources. Correcting this lagging power is usually served by adding capacitors in parallel with these loads. Capacitors store power and produce a leading power factor by adding current in the opposite direction of the inductive load; thereby effectively cancelling the current imbalance.
In actual operation, however, varying loads can induce instability in the voltage supply called harmonics. These can be caused by adjustable speed drives or starting and stopping loads which make up the normal operation in any business. Harmonics left unchecked can result in premature equipment failure, uncomfortable “flicker” in the lighting, or unreliable surge protection for delicate and expensive computer and office equipment. A properly corrected power factor system always includes a harmonic sweep and the addition of line filters if necessary.
Benefits
- Reduce electricity costs from 10% to 30%
- Enhance equipment operation by improving voltage stability
- Reduce line voltage drops to reduce current line losses
- Less wasted energy to line losses improves energy efficiency
- Free up transformer and distribution system capacity
Copyright 2009 NRG Management