8.2 POWER FACTOR

The cosine of the phase angle between two electrical quantities such as voltage and current in an AC circuit is known as power factor.

For instance, consider a load supplied by a voltage V and drawing a current of magnitude I, which lags the voltage by an angle ϕ. The phasor diagram of the circuit is given, in Fig. 8.1. The power factor of the circuit is given by,

Power Factor = Cos(ϕ)

The load current I can be resolved into two components.

  1. Horizontal component, I Cos ϕ in phase with the applied voltage V
  2. Vertical component, I Sin ϕ, 90° out of phase with the applied voltage V

The horizontal component, I Cos ϕ is known as active or wattful component and the vertical component, I Sin ϕ is known as the reactive or wattless component. ...

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