Power Factor Formula

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The power factor of an AC electrical power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit. Check FAQs
PF=VrmsIrmscos(φ)
PF - Power Factor?Vrms - Root Mean Square Voltage?Irms - Root Mean Square Current?φ - Phase Difference?

Power Factor Example

With values
With units
Only example

Here is how the Power Factor equation looks like with Values.

Here is how the Power Factor equation looks like with Units.

Here is how the Power Factor equation looks like.

18.809Edit=7Edit3.8Editcos(45Edit)
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Power Factor Solution

Follow our step by step solution on how to calculate Power Factor?

FIRST Step Consider the formula
PF=VrmsIrmscos(φ)
Next Step Substitute values of Variables
PF=7V3.8Acos(45°)
Next Step Convert Units
PF=7V3.8Acos(0.7854rad)
Next Step Prepare to Evaluate
PF=73.8cos(0.7854)
Next Step Evaluate
PF=18.8090403795649
LAST Step Rounding Answer
PF=18.809

Power Factor Formula Elements

Variables
Functions
Power Factor
The power factor of an AC electrical power system is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit.
Symbol: PF
Measurement: NAUnit: Unitless
Note: Value can be positive or negative.
Root Mean Square Voltage
Root Mean Square Voltage is the square root of the time average of the voltage squared.
Symbol: Vrms
Measurement: Electric PotentialUnit: V
Note: Value should be greater than 0.
Root Mean Square Current
Root Mean Square Current is defined as the root mean square of a given current.
Symbol: Irms
Measurement: Electric CurrentUnit: A
Note: Value should be greater than 0.
Phase Difference
Phase Difference between emf and current. Since in the AC circuits emf and current are always in phase with each other.
Symbol: φ
Measurement: AngleUnit: °
Note: Value can be positive or negative.
cos
Cosine of an angle is the ratio of the side adjacent to the angle to the hypotenuse of the triangle.
Syntax: cos(Angle)

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How to Evaluate Power Factor?

Power Factor evaluator uses Power Factor = Root Mean Square Voltage*Root Mean Square Current*cos(Phase Difference) to evaluate the Power Factor, The Power Factor formula is defined as the ratio of the real power absorbed by the load to the apparent power flowing in the circuit, and is a dimensionless number in the closed interval of −1 to 1. Power Factor is denoted by PF symbol.

How to evaluate Power Factor using this online evaluator? To use this online evaluator for Power Factor, enter Root Mean Square Voltage (Vrms), Root Mean Square Current (Irms) & Phase Difference (φ) and hit the calculate button.

FAQs on Power Factor

What is the formula to find Power Factor?
The formula of Power Factor is expressed as Power Factor = Root Mean Square Voltage*Root Mean Square Current*cos(Phase Difference). Here is an example- 18.80904 = 7*3.8*cos(0.785398163397301).
How to calculate Power Factor?
With Root Mean Square Voltage (Vrms), Root Mean Square Current (Irms) & Phase Difference (φ) we can find Power Factor using the formula - Power Factor = Root Mean Square Voltage*Root Mean Square Current*cos(Phase Difference). This formula also uses Cosine function(s).
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