1. What is Power Factor for 3 Phase Motor?

Definition: Power factor is the ratio of real power (kW) to apparent power (kVA) in a 3-phase AC electrical system.

Purpose: It measures how effectively electrical power is being used by a motor, with 1.0 being perfect efficiency.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( PF \) — Power factor (unitless, between 0 and 1)
• \( P_{kW} \) — Real power (kilowatts)
• \( V \) — Voltage (volts)
• \( I \) — Current (amps)

Explanation: The formula calculates the ratio of actual power being used to perform work versus the total power being drawn from the electrical system.

3. Importance of Power Factor

Details: A high power factor (close to 1) indicates efficient power usage, while a low power factor means poor utilization of electrical power and may result in higher utility charges.

4. Using the Calculator

Tips: Enter the motor's power rating in kW, operating voltage in volts, and current draw in amps. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a good power factor for motors?
A: Most 3-phase motors have a power factor between 0.85 and 0.95 at full load. Below 0.8 is considered poor.

Q2: Why does power factor matter?
A: Utilities often charge penalties for low power factor because it increases current flow and energy losses in distribution systems.

Q3: How can I improve power factor?
A: Power factor correction capacitors can be installed to reduce reactive power and improve the overall power factor.

Q4: Does power factor change with load?
A: Yes, power factor typically decreases as motor load decreases below its rated capacity.

Q5: What's the difference between leading and lagging power factor?
A: Lagging (most common) means current lags voltage (inductive load). Leading means current leads voltage (capacitive load).