1. What is Transformer Full Load Current?

The full load current of a transformer is the current drawn by the transformer when it is delivering its rated power (apparent power) at its rated voltage. It's a crucial parameter for sizing protection devices and conductors.

2. How Does the Calculator Work?

The calculator uses the transformer full load current formula:

Where:

• \( I \) — Full load current (amps)
• \( S \) — Apparent power (VA)
• \( V \) — Voltage (volts)

Explanation: The formula calculates the current drawn by a transformer when operating at its rated capacity.

3. Importance of Full Load Current Calculation

Details: Knowing the full load current is essential for proper circuit breaker selection, conductor sizing, and ensuring the transformer operates within its rated capacity.

4. Using the Calculator

Tips: Enter the transformer's apparent power in VA and its rated voltage in volts. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between full load current and inrush current?
A: Full load current is the steady-state current at rated load, while inrush current is the temporary high current when first energizing a transformer.

Q2: How does this differ for three-phase transformers?
A: For three-phase, use \( I = \frac{S}{\sqrt{3} \times V} \) where V is line-to-line voltage.

Q3: Why use VA instead of watts?
A: Transformers are rated in VA (apparent power) because it accounts for both real and reactive power.

Q4: What safety margin should I add?
A: Typically a 25% margin is added for continuous loads to account for variations and heat buildup.

Q5: How does temperature affect full load current?
A: Higher temperatures increase conductor resistance, which may slightly reduce current capacity.