1. What is the Electric Motor Power Formula?

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 energy consumption of electric motors.

2. How Does the Formula Work?

The formula 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 Motor Power Calculation

Details: Accurate power calculation ensures proper sizing of electrical systems, energy efficiency analysis, and cost estimation.

4. Using the Calculator

Tips: Enter the motor voltage (V), current (I), efficiency (default 0.9), and power factor (default 0.8). Efficiency and power factor must be between 0 and 1.

5. Frequently Asked Questions (FAQ)

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

Q2: What is power factor?
A: Power factor (PF) is the ratio of real power to apparent power, representing phase difference between voltage and current (typically 0.7-0.95).

Q3: Why not just multiply V × I?
A: V × I gives apparent power (VA). Multiplying by PF and η gives the actual power consumed and mechanical power delivered.

Q4: How do I find motor current?
A: Use a clamp meter or check motor nameplate. For three-phase motors, use the appropriate three-phase power formula.

Q5: Does this work for AC and DC motors?
A: For DC motors, PF=1. For AC motors, include the power factor as shown.