1. What is the 3 Phase Transformer kVA Formula?

Definition: This calculator computes the apparent power (kVA) of a three-phase transformer based on line voltage and current.

Purpose: It helps electrical engineers and technicians determine the proper transformer sizing for three-phase power systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{kVA} \) — Apparent power (kilovolt-amperes)
• \( V \) — Line-to-line voltage (volts)
• \( I \) — Line current (amps)
• \( \sqrt{3} \) — Constant for three-phase systems (≈1.732)

Explanation: The formula accounts for the phase difference in three-phase systems by multiplying by √3.

3. Importance of kVA Calculation

Details: Proper kVA calculation ensures transformers are correctly sized to handle the load without overheating or voltage drop issues.

4. Using the Calculator

Tips: Enter the line-to-line voltage in volts and line current in amps. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

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

Q2: Is this formula for line-to-line or line-to-neutral voltage?
A: This formula uses line-to-line voltage (phase-to-phase voltage).

Q3: Can I use this for single-phase calculations?
A: No, for single-phase use: kVA = (V × I) / 1000 (without the √3 factor).

Q4: What's the difference between kVA and kW?
A: kVA is apparent power (volts × amps), while kW is real power (volts × amps × power factor).

Q5: How does this relate to transformer sizing?
A: Transformers are rated in kVA, so this calculation helps select a transformer with adequate capacity.