Air Circuit Breaker (ACB) is an important component in electrical systems, which provides protection to the circuit from overload and short circuit.
It is very important to do the ACB setting correctly, as it ensures the safety and efficiency of the system.
Today we will discuss how to do 80% load setting and what parameters to consider.
IR (Overload Protection Setting): IR stands for Overload Protection setting, which is set as a percentage of the load current. For an 80% load setting, IR = 0.8In (where In is the nominal current).
Example: If the nominal current (In) is 1000A, then Ir = 0.8 * 1000 = 800A
TR (Time Delay for Overload Protection): TR is the time after which the breaker will trip under overload.
It is usually expressed in seconds and set according to the type of load.
Example: If tr = 10s is set, the breaker will trip if the 800A current flows for more than 10 seconds.
ISD (Short Circuit Protection Setting): ISD stands for Short Circuit Protection setting, which is set for short circuit current.
It is usually set as a multiple of IR, such as 5xlr or 10xlr.
Example: If IR = 800A then ISD = 5 x 800 = 4000A.
