We are not unaware that circuit breakers are vigilant watchdogs for any electrical circuit. Just as vigilantes ensure the safety of people in the area by preventing them from sleeping at night, so circuit breakers are always vigilant.
Load rating disconnects only when current flows in excess of current. Thus the circuit breaker protects the load from electrical accidents or short circuits. So far we all know. But today we will learn a more interesting topic. The topic is determining the braking capacity of a circuit breaker. Many may be wondering, what is the braking capacity of a circuit breaker? Let’s start the main chat.
As we already know, circuit breakers are the watchdogs of electrical systems. Now, the protector also has a limit of power and ability. If the vigilant guard falls into the hands of a strong wrestler, then he is gone !!!
Similarly the circuit breaker itself has a current tolerance. If there is a flow of electricity outside of this, he himself will get Akka by facing a short circuit. And as long as its tripping capacity works up to the label, it is called breaking capacity. If you keep an eye on the circuit breaker, you will see that there is a rating called kA. Whose full form is kiloampere. This is called breaking capacity. You can visit our blog to get a clearer concept about breaking capacity.
Now let’s come to the fun part. How do I determine the braking capacity without looking at the circuit breaker?
Suppose, I will determine the braking capacity of ACB / Air Circuit Breaker located in the Low Tension panel of the industry. Now it remains to be seen how many volts this breaker is consuming and how many power transformers have been used for the industry.
As we all know, the load side of the transformer enters the 440 volt ACB breaker. Then in this case,
V = 440 volt
Assuming, the rating of the transformer is 50 MVA
So, I = 50 MVA / √3 * 440 So, I = 50 MVA / √3 * 440
I = 65 kA
Now, we get 1.25 times as a safety factor,
I (breaking) = 65 x 1.25 = 82kA
This is how the braking capacity of a circuit breaker is calculated.
Multiplying this result by 2.55 gives the making capacity. InshaAllah we will talk about this making capacity another day.