serie rating of MCCB
serie rating of MCCB
(OP)
Hi,
We have a place with a lot of MCCB Westinghouse type F and FB and some Cutler-Hammer type FD and FDB.
The capacity of these breaker are 14 or 18 kA, but the short-cicuit current is way over.
The breakers are in serie with a current limiting fuse, type RK-5.
I have found serie rating chart for the Cutler-Hammer breaker with the fuse, but not for the Westinghouse.
Does anybody have this information available?
Thanks
We have a place with a lot of MCCB Westinghouse type F and FB and some Cutler-Hammer type FD and FDB.
The capacity of these breaker are 14 or 18 kA, but the short-cicuit current is way over.
The breakers are in serie with a current limiting fuse, type RK-5.
I have found serie rating chart for the Cutler-Hammer breaker with the fuse, but not for the Westinghouse.
Does anybody have this information available?
Thanks






RE: serie rating of MCCB
looking at the fuse curves, it appeared that the fuses would limit the fault current, but the dynamic impedance imposed when the breakers started to open ruined that thought process.
RE: serie rating of MCCB
Do you think that we cannot rely on this kind of chart?
RE: serie rating of MCCB
RE: serie rating of MCCB
RE: serie rating of MCCB
David Castor
www.cvoes.com
RE: serie rating of MCCB
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RE: serie rating of MCCB
I was thinking maybe someone have old litterature about this.
I think that it wasn't a bad conception at the time and people really take short circuit current into consideration. That's why they put current limiting fuse in serie, but without any written information I can't really make assumption. But maybe in the old days testing wasn't done for this setup like today as jraf said. Maybe they only made some calculation?
If it was a couple of breaker i wouldn't mind, just change it. But here are several hundred.
RE: serie rating of MCCB
Rafiq Bulsara
http://www.srengineersct.com