Motor KW Calculator

Motor Power Formula (3-Phase):

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

Motor Power (kW):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Motor KW Calculation?

Motor KW calculation determines the power consumption of three-phase electric motors using voltage, current, and power factor measurements. This helps in proper motor sizing, energy efficiency analysis, and electrical system design.

2. How Does the Calculator Work?

The calculator uses the three-phase motor power formula:

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

Where:

\( V \) — Voltage (volts)
\( I \) — Current (amps)
\( PF \) — Power Factor (0-1)
\( \sqrt{3} \) — Constant for three-phase systems (approximately 1.732)
\( 1000 \) — Conversion factor from watts to kilowatts

Explanation: The formula calculates real power in kilowatts by considering both the apparent power (V×I) and the power factor, which represents the phase difference between voltage and current.

3. Importance of Motor Power Calculation

Details: Accurate motor power calculation is essential for proper electrical system design, energy consumption monitoring, motor selection, and ensuring electrical safety by preventing overload conditions.

4. Using the Calculator

Tips: Enter voltage in volts, current in amps, and power factor as a decimal between 0 and 1. Typical power factors range from 0.8 to 0.95 for most industrial motors.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor and why is it important?
A: Power factor measures how effectively electrical power is converted into useful work. Low power factor indicates poor efficiency and may result in utility penalties.

Q2: Can this calculator be used for single-phase motors?
A: No, this calculator is specifically for three-phase motors. Single-phase motors use a different formula without the √3 factor.

Q3: What are typical power factor values for motors?
A: Induction motors typically have power factors between 0.8-0.9 at full load, dropping to 0.2-0.3 at no load. Synchronous motors can achieve unity power factor (1.0).

Q4: How does motor load affect power calculation?
A: Underloaded motors operate at lower power factors and efficiency. Always measure current under actual operating conditions for accurate calculations.

Q5: What is the difference between kW and kVA?
A: kW (kilowatts) represents real power, while kVA (kilovolt-amperes) represents apparent power. The ratio between them is the power factor (kW/kVA = PF).