3-Phase Motor Power Calculator

3-Phase Power Formula:

\[ P = \sqrt{3} \times V \times I \times PF \times \eta / 1000 \]

Voltage (V):

Current (I):

Power Factor (PF):

(0-1)

Efficiency (η):

(0-1)

Power Output:

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1. What is 3-Phase Motor Power Calculation?

The 3-phase motor power calculation determines the real power output of a three-phase electric motor based on voltage, current, power factor, and efficiency. This is essential for proper motor sizing, electrical system design, and energy efficiency analysis.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

\[ P = \sqrt{3} \times V \times I \times PF \times \eta / 1000 \]

Where:

\( P \) — Power output in kilowatts (kW)
\( V \) — Line-to-line voltage in volts (V)
\( I \) — Current in amperes (A)
\( PF \) — Power factor (unitless, 0-1)
\( \eta \) — Motor efficiency (unitless, 0-1)

Explanation: The formula accounts for all three phases (√3 factor) and converts the result to kilowatts by dividing by 1000.

3. Importance of Power Calculation

Details: Accurate power calculation is crucial for proper motor selection, electrical system design, energy consumption estimation, and determining mechanical load capacity.

4. Using the Calculator

Tips:

Measure voltage between any two phases (line-to-line)
Current should be measured per phase
Typical power factor for motors ranges from 0.8 to 0.95
Motor efficiency typically ranges from 0.85 to 0.95

5. Frequently Asked Questions (FAQ)

Q1: Why divide by 1000 in the formula?
A: The division converts watts to kilowatts (1 kW = 1000 W) for more convenient units in motor power ratings.

Q2: What's the difference between real power and apparent power?
A: Real power (kW) is the actual work output, while apparent power (kVA) includes reactive power. This calculator gives real power.

Q3: How does power factor affect the calculation?
A: Lower power factor means more current is required for the same real power output, reducing system efficiency.

Q4: Can I use this for single-phase motors?
A: No, single-phase motors use a different formula without the √3 factor.

Q5: How accurate are typical motor efficiency values?
A: Modern motors have nameplate efficiency ratings, but actual efficiency varies with load. At full load, actual efficiency is typically within 2% of nameplate.