Home
Back
3-Phase Power Formula:
| From: | To: |
The 3-phase power formula calculates current (amperes) from power (kilowatts), voltage, and power factor. It's essential for sizing wires, breakers, and other electrical components in three-phase systems.
The calculator uses the 3-phase current formula:
Where:
Explanation: The formula converts kW to watts (×1000), accounts for 3-phase power distribution (√3), and adjusts for power factor which represents the phase difference between voltage and current.
Details: Power factor (PF) indicates how effectively electrical power is converted to useful work. A PF of 1 is ideal (all power is real power), while lower PF values indicate reactive power that doesn't do useful work but still requires current flow.
Tips: Enter power in kW, line-to-line voltage in volts, and power factor (typically 0.8-0.95 for most industrial equipment). All values must be positive, with PF between 0 and 1.
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's a typical power factor value?
A: Induction motors typically have 0.85 PF, corrected systems 0.95+, and purely resistive loads 1.0.
Q3: Why does low power factor increase current?
A: More current is required to deliver the same real power when power factor is low due to reactive power component.
Q4: How does this differ from single-phase calculation?
A: Single-phase uses I = P/V without the √3 factor. 3-phase is more efficient for power distribution.
Q5: What if I know amps and want to find kW?
A: Rearrange the formula: \( kW = (\sqrt{3} \times V \times I \times PF) / 1000 \)