Cycles at Breaker (Switchgear)

The circuit breaker has to be capable of executing different operation cycles and achieve fast breaking of short circuit currents, the faster the better for the system. Recent progress has reduced the response time from 5 to 3 cycles down to 2 cycles.

If the above explanation is still unclear the following link clearly explains what is meant by 'cycle' when discussing electricity.

http://en.wikipedia.org/wiki/Frequency

More clearly, it is a time period in fraction of seconds.

For 60 Hz system, one cycle is 1/60 (≈ 0.0167) second

For 50 Hz system, one cycle is 1/50 (= 0.02) second

- MS

thank you for all of you, guys. . . . .

I've got the meaning clearer