1. What is Electrical Power?

Electrical power (measured in watts) is the rate at which electrical energy is transferred by an electric circuit. In AC circuits, the actual power consumed depends on both the voltage/current and the power factor.

2. How Does the Calculator Work?

The calculator uses the power formula:

For three-phase systems, the formula becomes:

Where:

• \( P \) — Power in watts (W)
• \( V \) — Voltage in volts (V)
• \( I \) — Current in amperes (A)
• \( PF \) — Power factor (unitless, between 0 and 1)
• \( \sqrt{3} \) — Approximately 1.732 (three-phase multiplier)

3. Importance of Power Calculation

Details: Accurate power calculation is essential for circuit design, electrical system sizing, energy consumption estimation, and equipment selection.

4. Using the Calculator

Tips: Enter voltage in volts, current in amperes, and power factor (1 for purely resistive loads). Select single-phase or three-phase system. All values must be valid (voltage > 0, current > 0, 0 ≤ PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted into useful work (typically 0.8-1 for most equipment).

Q2: Why multiply by √3 for three-phase?
A: In balanced three-phase systems, the total power is the sum of power in all three phases, which mathematically simplifies to √3 × line voltage × line current × PF.

Q3: What's typical power factor for different loads?
A: Resistive loads (heaters, incandescent lights) have PF=1. Motors typically 0.8-0.9. Electronic devices often 0.6-0.7.

Q4: How does power factor affect electrical bills?
A: Many utilities charge commercial customers for low power factor since it increases current requirements without delivering more useful power.

Q5: Can this calculator be used for DC circuits?
A: Yes, for DC just set PF=1 (DC has no power factor) and use single-phase option.