1. What is Transformer Size Calculation?

Transformer size calculation determines the appropriate transformer capacity (in kVA) required to handle a specific electrical load. Proper sizing ensures efficient operation, prevents overload, and maintains system reliability.

2. How Does the Calculator Work?

The calculator uses the transformer size formula:

Where:

• \( kVA \) — Transformer size 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, accounting for the phase relationship in balanced three-phase loads.

3. Importance of Transformer Sizing

Details: Proper transformer sizing is critical for energy efficiency, voltage regulation, system stability, and preventing equipment damage due to overload or underload conditions.

4. Using the Calculator

Tips: Enter the maximum expected current in amperes and the system voltage in volts. Ensure values are positive and represent the actual load conditions.

5. Frequently Asked Questions (FAQ)

Q1: Why use 1.732 in the formula?
A: 1.732 (√3) is used for three-phase systems to account for the phase difference between the three phases in balanced loads.

Q2: What's the difference between kVA and kW?
A: kVA represents apparent power (voltage × current), while kW represents real power. The ratio between them is the power factor (cos φ).

Q3: How do I account for future load growth?
A: Add a safety margin (typically 15-25%) to the calculated kVA to accommodate future load increases and prevent frequent transformer upgrades.

Q4: What about single-phase systems?
A: For single-phase systems, use the formula: kVA = (I × V) / 1000 (without the 1.732 factor).

Q5: How does power factor affect transformer sizing?
A: Lower power factors require larger transformers for the same real power. The formula calculates apparent power, which includes both real and reactive power components.