Power Factor of a Motor Calculator

Power Factor Formula (3-phase):

\[ PF = \frac{P_w}{V \times I \times \sqrt{3}} \]

Power Factor (PF):

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1. What is Power Factor of a Motor?

Definition: Power factor is the ratio of real power (watts) to apparent power (volt-amps) in an AC electrical system.

Purpose: It measures how effectively electrical power is converted into useful work output in a motor.

2. How Does the Calculator Work?

The calculator uses the formula for 3-phase systems:

\[ PF = \frac{P_w}{V \times I \times \sqrt{3}} \]

Where:

\( PF \) — Power factor (unitless, between 0 and 1)
\( P_w \) — Real power (watts)
\( V \) — Voltage (volts)
\( I \) — Current (amps)

Explanation: The formula compares the actual power being used to perform work against the total power flowing in the system.

3. Importance of Power Factor

Details: A higher power factor (closer to 1) indicates more efficient power usage, reduces energy losses, and may lower electricity costs.

4. Using the Calculator

Tips: Enter the motor's real power in watts, operating voltage, and current draw. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a good power factor for motors?
A: Most industrial motors have power factors 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 system losses.

Q3: How can I improve power factor?
A: Add power factor correction capacitors near inductive loads like motors.

Q4: Does this work for single-phase motors?
A: No, for single-phase use PF = P_w / (V × I) without the √3 factor.

Q5: What causes low power factor?
A: Inductive loads (like motors), underloaded motors, and phase imbalances can all reduce power factor.