1. What is Motor Efficiency?

Motor efficiency (η) is the ratio of mechanical power output to electrical power input, expressed as a percentage. It measures how effectively a brushless motor converts electrical energy into mechanical energy.

2. How Does the Calculator Work?

The calculator uses the efficiency formula:

Where:

• \( \eta \) — Motor efficiency (percentage)
• \( P_{out} \) — Mechanical output power (watts)
• \( P_{in} \) — Electrical input power (watts)

Explanation: The formula compares the useful power output to the total power consumed, with 100% representing perfect conversion (unattainable in practice).

3. Importance of Efficiency Calculation

Details: Efficiency calculation helps in selecting appropriate motors, estimating energy costs, and optimizing system performance. Higher efficiency means less energy waste as heat.

4. Using the Calculator

Tips: Enter both power values in watts. Output power should be measured at the motor shaft. Input power is the electrical power consumed (voltage × current × power factor).

5. Frequently Asked Questions (FAQ)

Q1: What is typical brushless motor efficiency?
A: Quality brushless motors typically achieve 80-95% efficiency under optimal operating conditions.

Q2: Why can't efficiency be 100%?
A: Losses occur due to resistance (I²R), friction, windage, and magnetic losses in the motor.

Q3: How does load affect efficiency?
A: Motors are most efficient at 70-90% of rated load. Efficiency drops significantly at very light or overload conditions.

Q4: Should I measure input power as DC or AC?
A: For brushless DC motors, measure DC input power before the controller for most accurate results.

Q5: How does temperature affect efficiency?
A: Higher temperatures increase resistance and typically decrease efficiency by 1-2% per 10°C rise.