1. What is AC Power Calculation?

The AC power calculation determines the real power in an alternating current circuit, accounting for voltage, current, and the power factor which represents the phase difference between voltage and current.

2. How Does the Calculator Work?

The calculator uses the AC power formula:

For three-phase systems, the formula becomes:

Where:

• \( P \) — Real 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 Factor

Details: Power factor represents the efficiency of power usage in an AC circuit. A PF of 1 means all power is real power (productive work), while lower values indicate reactive power (energy stored and returned to the system).

4. Using the Calculator

Tips: Enter voltage in volts, current in amperes, and power factor (typically between 0.8-1 for most equipment). Select single-phase or three-phase system.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between real, apparent, and reactive power?
A: Real power (W) does actual work, apparent power (VA) is the product of V×I, and reactive power (VAR) is the non-working power caused by phase shift.

Q2: Why is power factor important?
A: Low power factor means more current is needed for the same real power, increasing energy losses and potentially causing utility penalties.

Q3: What are typical power factor values?
A: Resistive loads (heaters, incandescent lights) have PF=1. Motors typically 0.8-0.9. Electronic power supplies often 0.6-0.7 without correction.

Q4: How does three-phase power differ from single-phase?
A: Three-phase provides more consistent power delivery and is more efficient for large loads, common in industrial settings.

Q5: Can this calculator be used for DC circuits?
A: For DC, simply use P=V×I (power factor is always 1 in pure DC circuits).