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Fuse Size Formula:
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The fuse size calculation for transformer determines the appropriate fuse rating needed to protect a transformer from overcurrent conditions. It ensures safe operation by preventing damage from electrical faults.
The calculator uses the formula:
Where:
Explanation: The formula calculates the full load current of the transformer and applies a 25% safety margin to determine the appropriate fuse size.
Details: Proper fuse sizing is critical for transformer protection, preventing damage from short circuits and overloads while allowing normal operation without nuisance tripping.
Tips: Enter the transformer kVA rating and system voltage. Both values must be positive numbers. The calculator will provide the recommended fuse size in amperes.
Q1: Why is a 1.25 safety factor used?
A: The 25% safety margin accounts for temporary overloads and ensures the fuse doesn't blow during normal operation while still providing adequate protection.
Q2: What if my transformer has multiple voltage taps?
A: Use the voltage setting that corresponds to your actual system voltage for accurate fuse sizing.
Q3: Can this formula be used for both primary and secondary protection?
A: This formula is typically used for primary side protection. Secondary protection may require different calculations based on specific application requirements.
Q4: What type of fuse should I use?
A: Time-delay fuses are commonly recommended for transformer protection as they allow for inrush currents without nuisance tripping.
Q5: Are there any exceptions to this calculation?
A: Special applications, unusual operating conditions, or specific manufacturer recommendations may require adjustments to this standard calculation.