Question

What is the phase angle and power factor of a pure inductor?

Answer 1

In a **pure inductor**:

### 1. **Phase Angle**:
The current lags behind the voltage by **90 degrees** (or π/2 radians). This is because in an inductor, the voltage across it leads the current due to the nature of inductive reactance. Therefore, the phase angle (ϕ) between the voltage and the current is:

\[
ϕ = 90^\circ \ (\text{or} \ \frac{\pi}{2} \ \text{radians})
\]

### 2. **Power Factor**:
The power factor (PF) is the cosine of the phase angle (ϕ) between the voltage and the current. For a pure inductor:

\[
\text{Power Factor (PF)} = \cos(90^\circ) = 0
\]

Since the power factor is 0, no real power is consumed by a pure inductor. The inductor only stores energy in its magnetic field and then releases it, leading to no net power consumption, and the power oscillates between the source and the inductor (this is called **reactive power**).

Answer 2

In a pure inductor, the phase angle between the voltage and current is 90 degrees. This means that the current lags the voltage by 90 degrees. Consequently, the power factor is 0, because the cosine of 90 degrees is 0. This indicates that a pure inductor does not contribute to real power; it only stores and returns energy to the circuit.