Dc circuit breaker sizing calculator

A DC circuit breaker sizing calculator is a tool used to determine the appropriate size of a DC circuit breaker for a given electrical circuit. Here's a simple calculator you can use:

DC Circuit Breaker Sizing Calculator

Inputs:

  1. Current Rating (I): The maximum current that the circuit is expected to carry, in amperes (A).
  2. Voltage (V): The voltage of the DC circuit, in volts (V).
  3. Fault Current (If): The maximum fault current that the circuit is expected to carry, in amperes (A). This is typically 1.5 to 2 times the current rating.
  4. Inrush Current (Iin): The maximum inrush current that the circuit is expected to carry, in amperes (A). This is typically 3 to 5 times the current rating.
  5. Circuit Type: The type of circuit (e.g., motor, lighting, power supply).

Calculations:

  1. DC Circuit Breaker Rating (Ib): Calculate the DC circuit breaker rating using the following formula:

Ib = √(I² * V)

Where Ib is the DC circuit breaker rating, I is the current rating, and V is the voltage.

  1. Fault Current Rating (Ifb): Calculate the fault current rating using the following formula:

Ifb = Ib * 1.5 to 2

Where Ifb is the fault current rating, Ib is the DC circuit breaker rating, and 1.5 to 2 is the fault current multiplier.

  1. Inrush Current Rating (Iinb): Calculate the inrush current rating using the following formula:

Iinb = Ib * 3 to 5

Where Iinb is the inrush current rating, Ib is the DC circuit breaker rating, and 3 to 5 is the inrush current multiplier.

Output:

The DC circuit breaker sizing calculator will output the recommended DC circuit breaker rating, fault current rating, and inrush current rating.

Example:

Suppose we have a DC circuit with a current rating of 10 A, a voltage of 12 V, a fault current of 15 A, and an inrush current of 30 A. The circuit type is a motor.

Using the calculator, we get:

Therefore, the recommended DC circuit breaker rating is 12.6 A, with a fault current rating of 22.05 A and an inrush current rating of 50.4 A.

Note:

This is a simplified calculator and actual calculations may vary depending on the specific application and requirements. It's always recommended to consult with a qualified electrical engineer or follow relevant industry standards (e.g., IEEE, IEC) for accurate calculations and sizing of DC circuit breakers.