Measuring Closing Time and Tripping Time of Breaker

Ah! Is this a 3-phase device being tested on a single phase supply, Captain? If so, then it's showing you the earliest opening time of any of the three contacts.

There is a product called the profile by Kelvatek which measures both single phase and 3 phase circuit breaker trip time. Was this the device you used? If so contact the manufacturer customer service as they know there stuff. There contact should be on their website.

If its a different device then cant help sorry:( but crabtree's comment sounds about right.

Can you give a simple sketch.

A diagram is much better than thousand words explanation.

How the test-Jig is wired ?

Closing time will depend on the activating circuit and the breakers closing circuit (the magnetic cct & the breakers closing mechanisms). The tripping time depends on the level of fault signal. Normal tripping initiations and other faults like phase faults usually takes longer tripping time than earth fault. Actually tripping time depends on the type of circuit breaker and their dependability tripping signal. An earth leakage circuit breaker will vary with the tripping time of the earth fault current levels. A current operated MCB will vary with tripping time of the out of balance current level. A voltage operated MCB will also vary with the operating fault voltage. NOTE: Time is an inverse function of magnitude factor. The more the magnitude factor, the lesser the time. John can fight John and any of them can win after a much longer round. But John Bull will beat john or knock John out in the first round. Dickson.