1. What is Transformer Size Calculation?

Transformer size calculation determines the appropriate kVA rating for a transformer based on the load current and voltage. Proper sizing ensures efficient operation and prevents overload conditions.

2. How Does the Calculator Work?

The calculator uses the transformer size formula:

Where:

• \( I \) — Current in amperes (A)
• \( V \) — Voltage in volts (V)
• 1.732 — Constant for three-phase systems (√3)
• 1000 — Conversion factor to kVA

Explanation: This formula calculates the apparent power in kilovolt-amperes required for a three-phase transformer based on the load current and system voltage.

3. Importance of Transformer Sizing

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

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why is the 1.732 factor used?
A: The factor 1.732 (√3) is used for three-phase power calculations to account for the phase relationship between voltages and currents.

Q2: Can this be used for single-phase systems?
A: For single-phase systems, use kVA = (I × V) / 1000 without the 1.732 factor.

Q3: What is typical transformer sizing margin?
A: Typically, transformers are sized with a 25-30% margin above the calculated load to account for future expansion and load variations.

Q4: How does power factor affect transformer sizing?
A: This calculation gives apparent power (kVA). For actual power (kW) consideration, the power factor must be taken into account: kW = kVA × PF.

Q5: Are there temperature considerations?
A: Yes, transformer ratings are typically given for specific ambient temperatures. Derating may be necessary for higher temperature environments.