1. What is the Power Formula?

The power formula P = V × I calculates electrical power from voltage and current. This fundamental equation in electrical engineering represents the rate at which electrical energy is transferred by an electric circuit.

2. How Does the Calculator Work?

The calculator uses the power formula:

Where:

• \( P \) — Power in watts (W)
• \( V \) — Voltage in volts (V)
• \( I \) — Current in amperes (A)

Explanation: This formula calculates the instantaneous electrical power in a DC circuit or the real power in an AC circuit when voltage and current are in phase.

3. Importance of Power Calculation

Details: Calculating motor power is essential for determining energy consumption, sizing electrical components, ensuring proper circuit protection, and evaluating motor efficiency and performance.

4. Using the Calculator

Tips: Enter voltage in volts and current in amperes. Both values must be positive numbers. The calculator will compute the power in watts.

5. Frequently Asked Questions (FAQ)

Q1: Does this formula work for AC circuits?
A: For AC circuits, this formula gives the real power only when voltage and current are in phase. For phase differences, use P = V × I × cos(φ) where φ is the phase angle.

Q2: 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).

Q3: How does motor efficiency affect power calculation?
A: The calculated power is electrical input power. Mechanical output power is less due to efficiency losses from heat, friction, and other factors.

Q4: Can I use this for three-phase systems?
A: For balanced three-phase systems, use P = √3 × V × I × cos(φ), where V is line voltage and I is line current.

Q5: What are typical power values for common motors?
A: Small motors might be 100W-1kW, while industrial motors can range from 1kW to several hundred kW, depending on application.