1. What is the Motor Power Formula?

The motor power formula calculates the real power consumption of a three-phase AC motor in kilowatts (kW). It takes into account the voltage, current, and power factor of the motor.

2. How Does the Calculator Work?

The calculator uses the three-phase power formula:

Where:

• \( P \) — Power in kilowatts (kW)
• \( V \) — Line-to-line voltage in volts (V)
• \( I \) — Current in amperes (A)
• \( PF \) — Power factor (unitless, between 0 and 1)
• \( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

Explanation: The formula calculates the real power (active power) consumed by the motor, accounting for the phase relationship between voltage and current in AC systems.

3. Importance of Motor Power Calculation

Details: Accurate motor power calculation is essential for sizing electrical components, determining energy consumption, assessing motor efficiency, and proper system design.

4. Using the Calculator

Tips: Enter the line-to-line voltage in volts, current in amps, and power factor (typically 0.8-0.95 for motors). All values must be positive numbers (voltage > 0, current > 0, 0 < PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What is power factor?
A: Power factor is the ratio of real power to apparent power, representing how effectively current is being converted into useful work.

Q2: What's typical power factor for motors?
A: Induction motors typically have power factors between 0.8-0.95 when fully loaded, lower when lightly loaded.

Q3: Is this formula for single-phase or three-phase?
A: This formula is specifically for three-phase systems. Single-phase uses P = V × I × PF / 1000.

Q4: How does motor efficiency factor in?
A: This formula calculates input power. Output power would multiply the result by motor efficiency (η).

Q5: What about motor starting current?
A: This calculates running power. Starting current can be 5-7 times running current but lasts only briefly.