cb rated operating sequence 2

[dalas]

hi,

what does it mean when a cb comes with "O-0.3 s-CO-3min-CO" as it's operating sequence rating?

thank you for any help

 

[Marmite]

This comes from IEC 62271-100, which is the specification for high voltage AC circuit breakers.
This is the appropriate text from the standard.

4.104 Rated operating sequence
The rated characteristics of the circuit-breaker are referred to the rated operating sequence.
There are two alternative rated operating sequences as follows:
a) O - t - CO - t' - CO
Unless otherwise specified:
t = 3 min for circuit-breakers not intended for rapid auto-reclosing;
t = 0,3 s for circuit-breakers intended for rapid auto-reclosing (dead time)
t' = 3 min.
NOTE Instead of t' = 3 min, other values: t' = 15 s and t' = 1 min are also used for circuit-breakers intended for
rapid auto-reclosing.
b) CO - t" - CO
with:
t" = 15 s for circuit-breakers not intended for rapid auto-reclosing
where
O represents an opening operation;
CO represents a closing operation followed immediately (that is, without any intentional
delay) by an opening operation;
t, t' and t'' are time intervals between successive operations;
t and t' should always be expressed in minutes or in seconds and
t'' should always be expressed in seconds.
If the dead time is adjustable, the limits of adjustment shall be specified.


Regards
Marmite

 

[slavag]

Hi.
Star to Marmite. You are speedy .
I'm only start write answer.
Best Regards.
Slava

 

[Marmite]

I probably had a slight advantage over you in time difference Slavag!
Thanks
Marmite