1. What is a 3 Phase Transformer Current Calculator?

Definition: This calculator determines the current (in amps) flowing through a three-phase transformer based on its kVA rating and line voltage.

Purpose: It helps electrical engineers and technicians properly size transformers and associated equipment.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( I \) — Current (amps)
• \( kVA \) — Transformer apparent power (kilovolt-amperes)
• \( V \) — Line voltage (volts)
• \( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

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

3. Importance of Current Calculation

Details: Accurate current calculation ensures proper conductor sizing, protection device selection, and prevents transformer overload.

4. Using the Calculator

Tips: Enter the transformer kVA rating and line voltage (default 480V). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why do we multiply by √3 in three-phase calculations?
A: √3 accounts for the phase difference (120°) between the three phases in a balanced system.

Q2: What's the difference between line and phase voltage?
A: Line voltage is between any two phases, while phase voltage is between a phase and neutral.

Q3: Does this work for both delta and wye configurations?
A: Yes, as long as you use the correct line voltage for your system.

Q4: How do I find the kVA rating of a transformer?
A: Check the nameplate or manufacturer specifications of the transformer.

Q5: What if I know the phase voltage instead of line voltage?
A: For wye systems, multiply phase voltage by √3 to get line voltage.