1. What is Motor Power Factor?

Definition: Power factor is the ratio of real power (kW) to apparent power (kVA) in an AC motor, representing how effectively electrical power is converted to useful work.

Typical Range: Most AC motors operate with power factors between 0.75 and 0.95, with 1.0 being perfect efficiency.

2. Why Power Factor Matters

Efficiency: Higher power factors indicate more efficient power usage and reduced energy waste.

Cost Impact: Utilities often charge penalties for low power factor (<0.85) as it strains the electrical grid.

3. Power Factor by Motor Type

• Single Phase Motors: 0.75-0.85
• Three Phase Motors: 0.80-0.90
• Induction Motors: 0.75-0.88 (varies with load)
• Synchronous Motors: 0.90-0.95 (can be adjusted)

4. Using This Calculator

Instructions: Select motor type and optionally enter motor horsepower for a more precise estimate.

5. Frequently Asked Questions (FAQ)

Q1: How does load affect power factor?
A: Power factor decreases significantly when motors operate below 75% load.

Q2: Can power factor be improved?
A: Yes, through capacitors, synchronous condensers, or using properly sized motors.

Q3: What's the difference between leading and lagging PF?
A: Lagging (common in motors) means current lags voltage; leading (capacitors) means current leads voltage.

Q4: Why do larger motors have better power factors?
A: They're typically more efficient with lower relative losses and better magnetic circuit design.

Q5: What power factor should I design for?
A: Target ≥0.90 for new installations to avoid utility penalties and reduce system losses.