Motor Power Kw Calculation Formula

Three-Phase Motor Power Formula:

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

Motor Power (kW):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Three-Phase Motor Power Calculation?

The three-phase motor power calculation formula determines the actual power consumption of a three-phase electric motor in kilowatts (kW). This calculation is essential for electrical engineering, motor selection, and energy efficiency analysis.

2. How Does the Calculator Work?

The calculator uses the three-phase power formula:

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

Where:

\( kW \) — Motor power in kilowatts
\( \sqrt{3} \) — Square root of 3 (approximately 1.732)
\( V \) — Line-to-line voltage in volts
\( I \) — Current in amperes
\( PF \) — Power factor (0 to 1)
\( 1000 \) — Conversion factor from watts to kilowatts

Explanation: The formula calculates real power by considering the three-phase system characteristics and power factor, which represents the phase difference between voltage and current.

3. Importance of Motor Power Calculation

Details: Accurate motor power calculation is crucial for proper motor sizing, energy consumption analysis, electrical system design, and determining operating costs in industrial and commercial applications.

4. Using the Calculator

Tips: Enter line-to-line voltage in volts, current in amperes, and power factor (typically 0.8-0.95 for motors). All values must be positive, with power factor between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is power factor and why is it important?
A: Power factor represents the efficiency of power usage. A lower power factor means more apparent power is required to deliver the same real power, increasing energy costs.

Q2: What is the typical power factor for electric motors?
A: Most three-phase induction motors have power factors between 0.85-0.95 at full load, decreasing at lower loads.

Q3: Can this formula be used for single-phase motors?
A: No, single-phase motors use a different formula: kW = (V × I × PF) / 1000, without the √3 factor.

Q4: What is the difference between real power and apparent power?
A: Real power (kW) does actual work, while apparent power (kVA) includes reactive power. The ratio is the power factor.

Q5: How does motor efficiency affect power calculation?
A: This formula calculates electrical input power. Mechanical output power would be input power multiplied by motor efficiency.