1. What is Electric Motor Power Rating?

The electric motor power rating represents the mechanical power output of the motor, typically measured in kilowatts (kW) or horsepower (HP). It's calculated from electrical input parameters considering the motor's efficiency and power factor.

2. How Does the Calculator Work?

The calculator uses the power formula:

Where:

• \( Voltage \) — Line voltage in volts (V)
• \( Current \) — Line current in amperes (A)
• \( Power\ Factor \) — Ratio of real power to apparent power (0-1)
• \( Efficiency \) — Motor efficiency (0-1)

Explanation: The formula converts electrical input power (VA) to mechanical output power (kW) by accounting for power factor (phase difference) and motor efficiency (energy losses).

3. Importance of Power Calculation

Details: Accurate power rating calculation is essential for motor selection, sizing electrical components, energy efficiency analysis, and proper system design.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, power factor (typically 0.8-0.95), and efficiency (typically 0.85-0.95 for most motors). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between kW and HP?
A: 1 HP ≈ 0.746 kW. kW is the SI unit while HP is an imperial unit of power.

Q2: What is a typical power factor for motors?
A: Usually 0.8-0.95 for AC induction motors at full load. Lower at partial loads.

Q3: How do I find motor efficiency?
A: Check motor nameplate or manufacturer specifications. Premium efficiency motors typically have 90-95% efficiency.

Q4: Is this calculation valid for three-phase motors?
A: For three-phase, multiply by √3 (1.732) for line-to-line voltage measurements.

Q5: Why divide by 1000 in the formula?
A: To convert watts to kilowatts (1 kW = 1000 W).