Answer / srinivasan.

open-300 millisec-Close /open-3min-Closeopen - means the
circuit breaker is capable of performing the above
operations even at full shorcuit currents.
At the same time the circuit breaker should not be allowed
to operate lesser than these timings.For example open-20
millisec-Close open-1 min-close/open.

This type of breakers are called single shot autoreclose
breakers.
Immediately after a fault breaking,we can do close open the
circuit breaker.

This sequence is tested during type testing only.

Answer / k.prakashchandra

CO means closing followed by opening.

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