3-Phase Motor Power Calculator

3-Phase Motor Power Formula:

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

Voltage (V):

Current (I):

Power Factor (PF):

(0-1)

Efficiency (η):

(0-1)

Power Output (P):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is 3-Phase Motor Power Calculation?

The 3-phase motor power calculation determines the actual power output of an electric motor based on electrical measurements. It accounts for voltage, current, power factor, and motor efficiency to provide accurate power consumption data.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

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

Where:

\( P \) — Power output (kW)
\( V \) — Line voltage (volts)
\( I \) — Line current (amperes)
\( PF \) — Power factor (0-1)
\( \eta \) — Motor efficiency (0-1)
\( \sqrt{3} \) — Constant for 3-phase systems
1000 — Conversion factor to kilowatts

Explanation: The formula calculates real power by accounting for both the apparent power (V×I) and the power factor (cosine of phase angle between voltage and current), then adjusts for motor efficiency.

3. Importance of Power Calculation

Details: Accurate power calculation is essential for motor sizing, energy consumption analysis, electrical system design, and determining operating costs.

4. Using the Calculator

Tips:

Measure voltage between any two phases (line-to-line voltage)
Measure current in one phase conductor
Typical power factor for motors ranges from 0.8 to 0.95
Motor efficiency typically ranges from 0.85 to 0.95 for standard efficiency motors

5. Frequently Asked Questions (FAQ)

Q1: Why use √3 in the formula?
A: The √3 factor accounts for the phase difference in 3-phase systems, converting line-to-line measurements to per-phase values.

Q2: What's the difference between real and apparent power?
A: Apparent power (kVA) is voltage × current, while real power (kW) is what actually does work, reduced by power factor.

Q3: How does power factor affect motor operation?
A: Lower power factor means more current is needed for the same real power, increasing losses and reducing system capacity.

Q4: When should I measure motor parameters?
A: Measure under normal operating load conditions, not at no-load or locked-rotor conditions.

Q5: How accurate is this calculation?
A: It provides good estimates but actual power may vary due to harmonics, voltage unbalance, and temperature effects.