1. What is the Power Formula for Electric Motors?

Definition: This formula calculates the real power consumption of an electric motor in watts, accounting for voltage, current, efficiency, and power factor.

Purpose: It helps engineers and technicians determine the actual power requirements and consumption of electric motors.

2. How Does the Formula Work?

The formula used is:

Where:

• \( P_w \) — Real power (watts)
• \( V \) — Voltage (volts)
• \( I \) — Current (amps)
• \( \eta \) — Motor efficiency (0-1)
• \( PF \) — Power factor (0-1)

Explanation: The formula multiplies voltage and current (apparent power) by efficiency and power factor to get the actual power consumed.

3. Importance of Power Calculation

Details: Accurate power calculation ensures proper motor sizing, energy efficiency assessment, and electrical system design.

4. Using the Calculator

Tips: Enter the motor's voltage, current, efficiency (default 0.9), and power factor (default 0.85). Efficiency and power factor must be between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is motor efficiency?
A: The ratio of mechanical power output to electrical power input, typically 0.7-0.95 for most motors.

Q2: What is power factor?
A: The ratio of real power to apparent power, representing phase difference between voltage and current (typically 0.8-0.95 for motors).

Q3: Why doesn't the formula just multiply V × I?
A: V × I gives apparent power (VA); multiplying by PF and η gives the actual power consumed and converted to mechanical energy.

Q4: How do I measure motor current?
A: Use a clamp meter to measure current while the motor is operating under normal load.

Q5: Can I use this for three-phase motors?
A: This formula is for single-phase. Three-phase requires multiplying by √3 (1.732).