Testing of Switchgear - Part 3 (Breaker operating timing test )

In previous blog, I discussed for Breaker Contact Resistance Measurement (CRM test) for switchgear. We will discuss further test in this post.

The next test we will discuss is as below.

Breaker Operating Timing Test

Purpose of the test :  

Circuit breaker is a part in electrical system which separates faulty part in event of fault. The separation time of the faulty part must be minimum and circuit breaker should do this quickly. This timing is called breaker operating time in which it removes the faulty part from system. Inside the breaker, it operates through mechanical operation. If this mechanism has any abnormality, then it will not operate smoothly and the breaker operating time will be more. When there is fault in the system, there will be high currents in the power circuit. Every equipment is designed to sustain for large current for very short time considering that circuit breaker will operate and will remove the fault from the system. If the circuit breaker will not operate within its desired time during the fault, there will be heavy damage to electrical equipment due to high currents. So we are checking the breaker closing and opening time through this test to ensure normal breaker timings.

Breaker Operating Time: Breaker operation time is total time of breaker closing time and opening time.

Breaker Opening Time: Breaker opening time is time between charging of tripping coil to separation of fixed and moving contact of breaker.

Breaker Closing Time: Breaker closing time is time between charging of closing coil to joining of fixed and moving contact of breaker.