Fusing Transformer Calculator | Easily Determine the Correct Fuse Size

Fusing Transformer Calculator enables you to easily determine the correct fuse size. A fusing transformer, also known as a protection transformer, is a type of transformer that provides overcurrent protection to the electrical circuit in which it is installed. By limiting the amount of current flowing through the circuit, the device reduces the risk of fires and electrical shocks and prevents damage to the circuit components.

Fusing Transformer Calculator – Determine the Correct Fuse Size for Transformer Protection

Transformer Power * (kVA)

Enter the rated power of the transformer in kilovolt-amperes (kVA).

Primary Voltage * (V)

Enter the transformer's primary (input) voltage in volts.

Phase Type * Single Phase Three Phase

Choose the transformer phase type.

Fuse Type * Standard (Non-Time Delay) Time-Delay (Slow-Blow)

Time-delay fuses allow brief inrush currents; standard fuses trip faster.

Inrush Consideration No (Normal Operation) Yes (High Inrush Expected)

Select "Yes" if the transformer has a high inrush current or is frequently switched on/off.

Example Presets:

10 kVA, 480 V, Three Phase, Time-Delay, Normal Inrush 2 kVA, 230 V, Single Phase, Standard, High Inrush 50 kVA, 600 V, Three Phase, Standard, Normal Inrush 0.5 kVA, 120 V, Single Phase, Time-Delay, Normal Inrush 25 kVA, 400 V, Three Phase, Time-Delay, High Inrush

Calculate Reset

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About Fusing Transformer Calculator and Formula:

A fusing transformer calculator calculates the fusing overcurrent protection amps using the transformer primary current and overcurrent protection factor.

It requires input values for the current in amps and the transformer size, which is chosen from a dropdown menu of three options: “Less than 2 amps,” “8+ amps,” and “2-7.99 amps.”

In this calculator, the fuse amps are output, which is the maximum current that the fuse or circuit breaker can safely carry.

FS = TA * OF

Where:

• FS is the fusing overcurrent protection amps
• TA is the transformer primary current in amps
• OF is the overcurrent protection factor, which depends on the size of the transformer

According to the problem statement, the overcurrent protection factor is:

• 500% for less than 2 amps
• 125% for 9 amps or more
• 167% for 2-8.99 amps

The calculator uses this information to calculate the fusing amps based on the input values. The fusing amps calculated by the calculator can be used to select the appropriate fuse or circuit breaker for the electrical circuit in which the transformer is installed.