Three Phase Motor Power Calculator

3-Phase Power Formula:

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

Power (P):

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1. What is 3-Phase Power Calculation?

The 3-phase power calculation determines the real power (in watts) consumed by a three-phase electrical system. It accounts for voltage, current, and the power factor which represents the phase difference between voltage and current.

2. How Does the Calculator Work?

The calculator uses the 3-phase power formula:

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

Where:

\( P \) — Real power in watts (W)
\( V \) — Line-to-line voltage in volts (V)
\( I \) — Current in amperes (A)
\( PF \) — Power factor (unitless, 0 to 1)
\( \sqrt{3} \) — Constant for 3-phase systems (≈1.732)

Explanation: The formula calculates the actual power being used (real power) as opposed to just the product of voltage and current (apparent power).

3. Importance of Power Factor

Details: Power factor (PF) represents the ratio of real power to apparent power. A higher PF (closer to 1) indicates more efficient power usage, while lower PF means more current is needed for the same real power.

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 valid (voltage > 0, current > 0, 0 ≤ PF ≤ 1).

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between line-to-line and line-to-neutral voltage?
A: In 3-phase systems, line-to-line voltage is √3 times the line-to-neutral voltage. This calculator uses line-to-line voltage.

Q2: What is a typical power factor for motors?
A: Induction motors typically have PF of 0.85 at full load, lower at partial loads. Synchronous motors can achieve PF of 1.0.

Q3: How does power factor affect energy costs?
A: Low PF may result in utility penalties as it requires more current for the same real power, increasing system losses.

Q4: Can this formula be used for single-phase systems?
A: No, single-phase power is calculated as P = V × I × PF (without the √3 factor).

Q5: What's the difference between real, apparent, and reactive power?
A: Real power (W) does actual work, apparent power (VA) is voltage × current, and reactive power (VAR) is needed for magnetic fields.