1. What is 3-Phase Power Calculation?

The 3-phase power calculation determines the real power consumed by a 3-phase electrical system. It accounts for the balanced three-phase voltage and current along with 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:

Where:

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

Explanation: The formula calculates the actual power being used (real power) as opposed to the apparent power (V×I). The power factor accounts for the phase difference between voltage and current.

3. Importance of Power Factor

Details: Power factor is crucial in electrical systems because it affects efficiency. A low power factor (typically <0.8) indicates poor utilization of electrical power, leading to higher current draw and energy losses.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's 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 star connections, line voltage = √3 × phase voltage.

Q2: What is a typical power factor 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 (1.0) power factor.

Q3: How can I improve power factor?
A: Power factor correction capacitors can be added to counteract inductive loads (like motors). Proper motor sizing and avoiding underloading also helps.

Q4: Does this calculation work for unbalanced loads?
A: This simplified formula assumes balanced 3-phase load. For unbalanced loads, each phase must be calculated separately and summed.

Q5: What about efficiency?
A: This calculates input power. Output power would include motor efficiency (typically 80-95% for electric motors).