1. What is the Transformer Size Calculation?

The transformer size calculation determines the required kilovolt-ampere (KVA) rating for a three-phase transformer based on voltage and current values. Proper sizing ensures efficient power distribution and prevents equipment damage.

2. How Does the Calculator Work?

The calculator uses the three-phase transformer formula:

Where:

• \( V \) — Voltage (volts)
• \( I \) — Current (amps)
• \( \sqrt{3} \) — Constant for three-phase systems (approximately 1.732)
• 1000 — Conversion factor to kilovolt-amperes

Explanation: This formula calculates the apparent power in a three-phase electrical system, which is essential for proper transformer selection.

3. Importance of Transformer Sizing

Details: Correct transformer sizing is crucial for efficient power distribution, preventing overload conditions, ensuring system reliability, and optimizing energy efficiency in electrical systems.

4. Using the Calculator

Tips: Enter voltage in volts and current in amps. Both values must be positive numbers. The calculator will compute the required transformer size in KVA.

5. Frequently Asked Questions (FAQ)

Q1: Why is the √3 factor used in three-phase calculations?
A: The √3 factor accounts for the phase difference in three-phase systems, converting line-to-line voltage and current to the total power in the system.

Q2: What's the difference between KVA and KW?
A: KVA measures apparent power (voltage × current), while KW measures real power (actual power consumed). The ratio between them is the power factor.

Q3: When should I use this calculation?
A: Use this calculation when sizing transformers for industrial applications, commercial buildings, or any three-phase electrical distribution system.

Q4: Are there limitations to this formula?
A: This formula provides basic sizing. Additional factors like load type, power factor, ambient temperature, and future expansion should be considered for precise sizing.

Q5: How do I account for motor starting currents?
A: For motor applications, transformers should be sized to handle the higher starting currents, typically 150-200% of the running current.