1. What is VA (Volt-Amperes)?

VA (volt-amperes) represents apparent power in an AC electrical system, which is the product of the RMS voltage and RMS current. It differs from watts (real power) because it accounts for the phase difference between voltage and current caused by reactive loads.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VA \) — Apparent power in volt-amperes
• \( P \) — Real power in watts
• \( PF \) — Power factor (unitless, between 0 and 1)

Explanation: The power factor represents the ratio of real power to apparent power. For purely resistive loads, PF = 1 and VA = watts.

3. Importance of Power Factor

Details: Power factor indicates how effectively electrical power is converted to useful work. Low power factor means more current is required to deliver the same real power, increasing losses in distribution systems.

4. Using the Calculator

Tips: Enter real power in watts and power factor (typically between 0.7 and 1 for most equipment). Power factor must be between 0.01 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between watts and VA?
A: Watts measure real power (actual work done), while VA measures apparent power (voltage × current). VA is always equal to or greater than watts.

Q2: Why is power factor important?
A: Electrical systems must be sized for VA, not just watts. Low power factor means you need larger wires and equipment to deliver the same real power.

Q3: What are typical power factor values?
A: Resistive loads (heaters, incandescent lights) have PF=1. Motors typically 0.8-0.9. Computers/electronics often 0.6-0.7.

Q4: When is VA more important than watts?
A: For sizing transformers, wiring, and circuit breakers, VA is critical because these components must handle the total current.

Q5: Can power factor be greater than 1?
A: No, power factor ranges from 0 to 1. Values above 1 would violate energy conservation laws.