1. What is Electric Motor Power Calculation?

The electric motor power calculation determines the real power (in kW) consumed by a three-phase AC motor based on voltage, current, and power factor. This is essential for sizing motors, calculating energy consumption, and electrical system design.

2. How Does the Calculator Work?

The calculator uses the three-phase power formula:

Where:

• \( P \) — Power in kilowatts (kW)
• \( V \) — Line-to-line voltage in volts (V)
• \( I \) — Current in amperes (A)
• \( PF \) — Power factor (unitless, 0-1)
• \( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

Explanation: The formula accounts for the phase relationship in three-phase systems and converts the result to kilowatts by dividing by 1000.

3. Importance of Power Calculation

Details: Accurate power calculation is crucial for proper motor selection, energy efficiency analysis, electrical system design, and determining operating costs.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts, current in amps, and power factor (typically 0.8-0.95 for motors). All values must be positive (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 0.8-0.95 for motors).

Q2: Why use √3 in the calculation?
A: The √3 factor accounts for the phase difference in three-phase systems, converting line-to-line voltage to phase voltage.

Q3: Can this be used for single-phase motors?
A: No, single-phase motors use P = V × I × PF / 1000 (without the √3 factor).

Q4: What's typical power factor for motors?
A: Induction motors typically have PF of 0.85 at full load, lower at partial loads. Synchronous motors can achieve PF of 1.0.

Q5: How does voltage affect power?
A: Power is directly proportional to voltage. A 10% voltage drop results in about 10% power reduction (assuming current remains constant).