1. What is AC Real Power?

AC real power (also known as active power) is the actual power consumed by electrical equipment to perform useful work. In AC circuits, it differs from apparent power due to the phase difference between voltage and current caused by reactive components.

2. How Does the Calculator Work?

The calculator uses the AC real power formula:

Where:

• \( P \) — Real power in watts (W)
• \( V \) — Voltage in volts (V)
• \( I \) — Current in amperes (A)
• \( PF \) — Power factor (dimensionless, 0-1)

Explanation: The power factor accounts for the phase difference between voltage and current in AC circuits. A power factor of 1 indicates purely resistive load, while lower values indicate reactive components.

3. Importance of Power Factor

Details: Power factor is crucial in AC power systems because it affects the efficiency of power transmission and distribution. Low power factor results in higher current for the same real power, increasing energy losses and requiring larger conductors.

4. Using the Calculator

Tips: Enter voltage in volts, current in amperes, and power factor as a decimal between 0 and 1. All values must be positive, with power factor ranging from 0 to 1 inclusive.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between real power and apparent power?
A: Real power (P) is the actual power consumed, measured in watts. Apparent power (S) is the product of voltage and current, measured in volt-amperes (VA). The ratio P/S is the power factor.

Q2: What causes low power factor?
A: Low power factor is typically caused by inductive loads like motors, transformers, and fluorescent lighting that create phase shift between voltage and current.

Q3: How can power factor be improved?
A: Power factor can be improved by adding capacitors in parallel with inductive loads, using synchronous motors, or employing power factor correction equipment.

Q4: What is a typical power factor value?
A: Residential power factors are typically 0.85-0.95, industrial facilities range from 0.70-0.90, and purely resistive loads have a power factor of 1.0.

Q5: Why do utilities charge for low power factor?
A: Utilities often impose penalties for low power factor because it increases transmission losses and requires larger infrastructure to deliver the same real power.