Three Phase Motor Power Calculator

3-Phase Power Formula:

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

Voltage (V):

Volts

Current (I):

Amps

Power Factor (PF):

(0-1)

Efficiency (η):

(0-1)

Power (P):

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1. What is 3-Phase Power Calculation?

The 3-phase power calculation determines the real power consumed by a three-phase motor or electrical system. It accounts for voltage, current, power factor, and efficiency to provide accurate power measurement in kilowatts (kW).

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 in kilowatts (kW)
\( V \) — Line-to-line voltage (Volts)
\( I \) — Current (Amperes)
\( PF \) — Power factor (0-1)
\( \eta \) — Efficiency (0-1)

Explanation: The √3 factor accounts for the phase difference in three-phase systems. The power factor represents the ratio of real power to apparent power, and efficiency accounts for energy losses in the motor.

3. Importance of Power Calculation

Details: Accurate power calculation is essential for sizing electrical components, determining energy consumption, calculating operating costs, and ensuring proper motor selection for applications.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts, current in amps, power factor (typically 0.8-0.95 for motors), and efficiency (typically 0.8-0.95 for motors). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between line and phase voltage?
A: In 3-phase systems, line voltage is between any two lines, while phase voltage is between any line and neutral. For delta connections, line voltage equals phase voltage.

Q2: Why divide by 1000 in the formula?
A: The division converts watts to kilowatts (1 kW = 1000 W) for more practical power measurements.

Q3: What is a typical power factor for motors?
A: Induction motors typically have power factors between 0.8-0.9 at full load, lower at partial loads.

Q4: How does efficiency affect power calculation?
A: Efficiency accounts for energy losses (heat, friction). A motor with 90% efficiency converts 90% of electrical input to mechanical output.

Q5: Can this be used for single-phase systems?
A: No, single-phase power calculation uses P = V × I × PF / 1000 (without the √3 factor).