1. What is a Transformer Size Calculator?

Definition: This calculator determines the required transformer size in kilovolt-amperes (kVA) based on voltage and current values.

Purpose: It helps electrical engineers and technicians properly size transformers for various applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( kVA \) — Transformer size (kilovolt-amperes)
• \( V \) — Voltage (volts)
• \( I \) — Current (amps)

Explanation: The product of voltage and current is divided by 1000 to convert from volt-amperes to kilovolt-amperes.

3. Importance of Proper Transformer Sizing

Details: Correct transformer sizing ensures efficient power distribution, prevents overload conditions, and maintains system reliability.

4. Using the Calculator

Tips: Enter the voltage in volts and current in amps. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Is this for single-phase or three-phase transformers?
A: This formula is for single-phase transformers. Three-phase calculations require an additional factor (√3).

Q2: Should I add a safety margin to the calculated kVA?
A: Yes, it's common practice to add 20-25% to the calculated value for safety and future expansion.

Q3: What's the difference between kVA and kW?
A: kVA is apparent power (voltage × current), while kW is real power (kVA × power factor).

Q4: Can I use this for DC circuits?
A: No, transformers only work with AC. For DC, you would use different conversion equipment.

Q5: How do I account for transformer efficiency?
A: Typical efficiency is 95-98%. Divide your calculated kVA by the efficiency factor (0.95 to 0.98) for more precise sizing.