Circuit breaker trip time calculator

A circuit breaker trip time calculator is a tool used to determine the time it takes for a circuit breaker to trip in response to a fault or overload in an electrical circuit. The trip time is an important parameter in electrical engineering and is used to ensure the safety and reliability of electrical systems.

Here is a simple calculator that can be used to estimate the trip time of a circuit breaker:

Circuit Breaker Trip Time Calculator

Inputs:

  1. Fault Current (I_f): The current flowing through the circuit when the fault occurs (in amperes).
  2. Nominal Current (I_n): The rated current of the circuit breaker (in amperes).
  3. Time-Domain Current (I_t): The current flowing through the circuit at the time of the fault (in amperes).
  4. Time Constant (τ): The time constant of the circuit breaker (in seconds).
  5. Trip Threshold (I_trip): The current threshold at which the circuit breaker trips (in amperes).

Calculations:

  1. Fault Current Ratio (FCR): FCR = I_f / I_n
  2. Time-Domain Current Ratio (TDCR): TDCR = I_t / I_n
  3. Trip Time (t_trip): t_trip = τ * ln(FCR / TDCR)

Where:

Example:

Suppose we have a circuit breaker with a nominal current of 100 A, a time constant of 0.1 seconds, and a trip threshold of 150 A. If a fault occurs and the current flowing through the circuit is 200 A, how long will it take for the circuit breaker to trip?

Inputs:

Calculations:

  1. FCR = 200 A / 100 A = 2
  2. TDCR = 200 A / 100 A = 2
  3. t_trip = 0.1 s * ln(2 / 2) = 0.0693 seconds

Result:

The circuit breaker will trip in approximately 0.0693 seconds.

Please note that this is a simplified calculator and the actual trip time may vary depending on the specific circuit breaker and the fault conditions. It is always recommended to consult the manufacturer's documentation and perform more detailed calculations to ensure the accuracy of the trip time estimate.