1. What is 3 Phase Current Calculation?

The 3 phase current calculation determines the current flowing through each phase of a three-phase transformer or load. This is essential for proper sizing of conductors, protection devices, and transformer capacity.

2. How Does the Calculator Work?

The calculator uses the 3 phase current formula:

Where:

• \( I_{phase} \) — Phase current in amps
• \( kVA \) — Transformer kilovolt-amp rating
• \( V_{line} \) — Line-to-line voltage in volts
• \( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

Explanation: The formula converts kVA to VA (×1000), then divides by phase voltage (line voltage/√3) to get current.

3. Importance of Current Calculation

Details: Accurate current calculation is crucial for electrical system design, ensuring proper conductor sizing, overload protection, and preventing equipment damage.

4. Using the Calculator

Tips: Enter transformer kVA rating and line voltage in volts. Both values must be positive numbers. The calculator will output the phase current in amperes.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between line and phase current?
A: In delta systems, line current is √3 times phase current. In wye systems, they're equal.

Q2: How does voltage affect the current?
A: Higher voltage systems require less current for the same power (kVA) due to the inverse relationship in the formula.

Q3: When should I use this calculation?
A: For sizing transformers, circuit breakers, fuses, conductors, and determining load capacity.

Q4: What about power factor?
A: This formula assumes unity power factor (1.0). For non-unity PF, use: I = kVA×1000/(V×√3×PF).

Q5: Is this for primary or secondary side?
A: The formula works for either side - just use the appropriate kVA and voltage for the side you're calculating.