Medium voltage switchgear application guide

Medium voltage switchgear application guide
Appendix 8: fused
switch-disconnector or
fused contactor (cont’d)
2 - DEVICE FUNCTIONS
Each associated element ensures different and complementary functions.
The role of the switch or
■make or break the load
contactoris
current, to:
■break ■cause fault three-phase currents tripping which are as not a result high of enough fuse breaking. to melt the fuse,
The role of the fuse is to:
■break ■limit switching short-circuit currents currents,
■steadily withstand the load (in the current event without of a fault excessive circuit being overheating produced),
depending on the installation and/or operating conditions.
date
11/94
- B•3•2 -
revised
05/2004
page 16