3 Phase Ampacity Calculator

3 Phase Ampacity Formula:

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

Current (I):

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1. What is the 3 Phase Ampacity Formula?

The 3 phase ampacity formula calculates the current (I) in a three-phase electrical system based on power (P), voltage (V), and power factor (PF). It provides an accurate assessment of current flow in balanced three-phase systems.

2. How Does the Calculator Work?

The calculator uses the 3 phase ampacity formula:

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

Where:

\( I \) — Current in amperes (amps)
\( P \) — Power in watts
\( V \) — Voltage in volts
\( PF \) — Power factor (dimensionless, between 0 and 1)
\( \sqrt{3} \) — Approximately 1.732 (dimensionless)

Explanation: The formula accounts for the three-phase power system characteristics, where the √3 factor comes from the phase relationship between the three phases.

3. Importance of Ampacity Calculation

Details: Accurate current calculation is crucial for proper electrical system design, circuit breaker sizing, wire selection, and ensuring safe operation of electrical equipment in three-phase systems.

4. Using the Calculator

Tips: Enter power in watts, voltage in volts, and power factor (between 0 and 1). All values must be valid (positive numbers, power factor between 0-1).

5. Frequently Asked Questions (FAQ)

Q1: What is power factor and why is it important?
A: Power factor represents the ratio of real power to apparent power. It's important because it affects the actual current drawn by a load and system efficiency.

Q2: When should I use this formula?
A: Use this formula for balanced three-phase AC systems to calculate current based on known power, voltage, and power factor.

Q3: What are typical power factor values?
A: Power factor typically ranges from 0 to 1. Resistive loads have PF near 1, while inductive loads (motors, transformers) have lower PF values (0.7-0.9).

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

Q5: What if I don't know the power factor?
A: For rough estimates, you can use PF = 0.8-0.9 for motor loads or PF = 1 for resistive loads, but accurate calculations require the actual power factor.