Power factor free online calculator

Power factor calculator. Calculate power factor, apparent power, reactive power and correction capacitor's capacitance.

This calculator is for educational purposes.

kW
A
V
Hz
kVA
kVAR
µF

The power factor correction capacitor should be connected in parallel to each phase load.

The power factor calculation does not distinguish between leading and lagging power factors.

The power factor correction calculation assumes inductive load.

Single phase circuit calculation

Power factor calculation:

PF = |cos φ| = 1000 × P(kW) / (V(V) × I(A))

Apparent power calculation:

|S(kVA)| = V(V) × I(A) / 1000

Reactive power calculation:

Q(kVAR) = √(|S(kVA)|2 - P(kW)2)

Power factor correction capacitor's capacitance calculation:

Scorrected (kVA) = P(kW) / PFcorrected

Qcorrected (kVAR) = √(Scorrected (kVA)2 - P(kW)2)

Qc (kVAR) = Q(kVAR) - Qcorrected (kVAR)

C(F) = 1000 × Qc (kVAR) / (2πf(Hz)×V(V)2)

Three phase circuit calculation

For three phase with balanced loads:

Calculation with line to line voltage

Power factor calculation:

PF = |cos φ| = 1000 × P(kW) / (3 × VL-L(V) × I(A))

Apparent power calculation:

|S(kVA)| = 3 × VL-L(V) × I(A) / 1000

Reactive power calculation:

Q(kVAR) = √(|S(kVA)|2 - P(kW)2)

Power factor correction capacitor's capacitance calculation:

Qc (kVAR) = Q(kVAR) - Qcorrected (kVAR)

C(F) = 1000 × Qc (kVAR) / (2πf(Hz)×VL-L(V)2)

Calculation with line to neutral voltage

Power factor calculation:

PF = |cos φ| = 1000 × P(kW) / (3 × VL-N(V) × I(A))

Apparent power calculation:

|S(kVA)| = 3 × VL-N(V) × I(A) / 1000

Reactive power calculation:

Q(kVAR) = √(|S(kVA)|2 - P(kW)2)

Power factor correction capacitor's capacitance calculation:

Qc (kVAR) = Q(kVAR) - Qcorrected (kVAR)

C(F) = 1000 × Qc (kVAR) / (3×2πf(Hz)×VL-N(V)2)

Power factor definition

In electrical engineering, 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, and is a dimensionless number in the closed interval of −1 to 1. A power factor of less than one indicates the voltage and current are not in phase, reducing the average product of the two. Real power is the instantaneous product of voltage and current and represents the capacity of the electricity for performing work. Apparent power is the product of RMS current and voltage. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power may be greater than the real power. A negative power factor occurs when the device (which is normally the load) generates power, which then flows back towards the source.

In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor.

Power-factor correction increases the power factor of a load, improving efficiency for the distribution system to which it is attached. Linear loads with low power factor (such as induction motors) can be corrected with a passive network of capacitors or inductors. Non-linear loads, such as rectifiers, distort the current drawn from the system. In such cases, active or passive power factor correction may be used to counteract the distortion and raise the power factor. The devices for correction of the power factor may be at a central substation, spread out over a distribution system, or built into power-consuming equipment.


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