1. What is the Motor Power Formula?

Definition: This formula calculates the actual power output of an electric motor in watts based on voltage, current, efficiency, and power factor.

Purpose: It helps engineers and technicians determine the real power consumption and output of electric motors.

2. How Does the Formula Work?

The formula used is:

Where:

• \( P_w \) — Motor power output (watts)
• \( V \) — Voltage supplied to the motor (volts)
• \( I \) — Current drawn by the motor (amps)
• \( \eta \) — Motor efficiency (0 to 1)
• \( PF \) — Power factor (0 to 1)

Explanation: The formula multiplies voltage and current to get apparent power, then factors in efficiency and power factor to determine real power output.

3. Importance of Motor Power Calculation

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

4. Using the Calculator

Tips: Enter the voltage in volts, current in amps, 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: 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 0.8-0.95).

Q3: Why multiply by both efficiency and power factor?
A: Efficiency accounts for energy losses in the motor, while power factor accounts for reactive power in AC systems.

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

Q5: Can I use this for DC motors?
A: Yes, for DC motors set power factor = 1 (no phase difference in DC).