Typical Power Factors for Common Electrical Loads

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Power factor is very critical for calculating or measuring the electrical power consumed by an electrical device on an alternating current supply. To be able to determine electrical power on alternating current (AC) systems, you need to know the power factor of the electrical load. Below is listed the  typical power factors for common electrical loads:


Electrical Load Power Factor (CosŐ“) Reactive Demand Factor (TanŐ“)
Transformers (No load condition)
 0.1 - 0.15 9.9 - 6.6
Motor (Full load)
 0.7 - 0.85 1.0 - 0.62
Motor (No load)
 0.15 6.6



Metal Working Apparatuses:

  • Arc Welding
 0.35 - 0.6 2.7 - 1.3

  • Arc Welding  Compensated
 0.7 - 0.8 1.0 - 0.75

  • Resistance Welding
 0.4 - 0.6 2.3 - 1.3

  • Arc Melting Furnance
 0.75 - 0.9 0.9 - 0.5
Fluorescent Lamps:

  • Compensated
 0.9 0.5

  • Uncompensated
 0.4 - 0.6 2.3 - 1.3
Mercury Vapor Lamps
 0.5 1.7
Sodium Vapor Lamps
 0.65 - 0.75 1.2 - 0.9
AC DC Converters
 0.6 - 0.95 1.3 - 0.3
DC Drives
 0.4 - 0.75 2.3 - 0.9
AC Drives
 0.95 - 0.97 0.33 - 0.25
Resistive Load
 1 0


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