3 Phase Motor Power Calculator

3-Phase Power Formula:

\[ P_{kW} = \frac{V \times I \times PF \times \sqrt{3}}{1000} \]

Power (P_kW): kW

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1. What is a 3 Phase Motor Power Calculator?

Definition: This calculator estimates the power consumption of a three-phase electric motor based on voltage, current, and power factor.

Purpose: It helps electrical engineers, technicians, and maintenance personnel determine motor power requirements and energy consumption.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_{kW} = \frac{V \times I \times PF \times \sqrt{3}}{1000} \]

Where:

\( P_{kW} \) — Power in kilowatts (kW)
\( V \) — Line-to-line voltage (volts)
\( I \) — Current (amps)
\( PF \) — Power factor (0 to 1)
\( \sqrt{3} \) — Constant for 3-phase systems (≈1.732)

Explanation: The formula accounts for all three phases in the system and converts the result to kilowatts.

3. Importance of Power Calculation

Details: Accurate power calculation helps in sizing electrical components, estimating energy costs, and ensuring system efficiency.

4. Using the Calculator

Tips: Enter the line-to-line voltage in volts, current in amps, and power factor (default 0.85). Power factor must be between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing system efficiency (typically 0.8-0.95 for motors).

Q2: Should I use line-to-line or line-to-neutral voltage?
A: Always use line-to-line (phase-to-phase) voltage for this calculation.

Q3: What's a typical power factor for motors?
A: Induction motors typically have 0.85 PF at full load, but this varies with load and motor type.

Q4: How do I measure current for this calculation?
A: Use a clamp meter to measure the current in one phase while the motor is running.

Q5: Can I calculate horsepower from this result?
A: Yes, 1 HP ≈ 0.746 kW, so divide kW by 0.746 to get horsepower.