1. What is Transformer Sizing?

Transformer sizing is the process of determining the appropriate capacity (in kVA) of a transformer based on the electrical load requirements. Proper sizing ensures efficient operation, prevents overload, and extends equipment lifespan.

2. How Does the Calculator Work?

The calculator uses the transformer sizing formula:

Where:

• \( kVA \) — Transformer capacity in kilovolt-amperes
• \( I \) — Current in amperes (A)
• \( V \) — Voltage in volts (V)
• \( 1.732 \) — Square root of 3 (for three-phase systems)

Explanation: This formula calculates the apparent power requirement for three-phase systems, which is essential for selecting the right transformer size.

3. Importance of Proper Transformer Sizing

Details: Correct transformer sizing is crucial for energy efficiency, voltage regulation, system reliability, and preventing equipment damage due to overload or underload conditions.

4. Using the Calculator

Tips: Enter current in amperes and voltage in volts. The calculator assumes a three-phase system. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is 1.732 used in the formula?
A: 1.732 (√3) is the conversion factor for three-phase power calculations, accounting for the phase relationship between voltages.

Q2: Is this formula for single-phase or three-phase systems?
A: This specific formula with the 1.732 factor is for three-phase systems. For single-phase, use kVA = (I × V) / 1000.

Q3: What safety margin should be added to the calculated kVA?
A: Typically, a 15-25% safety margin is added to account for future load growth and transient overload conditions.

Q4: How does power factor affect transformer sizing?
A: This formula calculates apparent power (kVA). For real power requirements (kW), the power factor must be considered: kW = kVA × PF.

Q5: What are common standard transformer sizes?
A: Common sizes include: 5, 10, 15, 25, 37.5, 50, 75, 100, 150, 200, 300, 500, 750, 1000 kVA and larger.