Fuses; Trigger Fuses And Open Fuse Trip Attachment; Key Interlock System - Siemens RL Series Instructions Manual

Fuse Carriage

Fuses

O n ly special purpose fuses i n acco rdance with Siemens
drawing number 7 1 -1 42-200 can be used with the circuit
breaker/fuse carriage combination. Fuses which do not
conform to this specification will not mount properly on the
fuse carriage terminals.
Only fuses of the same current rating should be used for
replacement of any open fuses.

Trigger Fuses and Open Fuse Trip Attachment

A WARNING
Hazardous voltage.
Can cause death, serious personal injury,
trical shock burns, or property damage.
be
Line voltage may
not
assembly Do remove trigger fuse cover when
circuit or luse
breaker
posit1on.
The fuse carriage has provisions for mounting three trigger
fuses that are connected in parallel with the main power
fuses. They are used to indicate which of the power fuses
opened under a system fault Operation of the open-fuse trip
attachment is indicated by movement of its reset handle to a
horizontal position
The breaker-mounted open-fuse trip attachment holds the
circuit breaker in its tripped position, and the circuit breaker
cannot be re-closed until the open-fuse trip attachment is
reset manually. The trigger fuses should also be replaced
when replacing the main power fuses if open phase
indication is desired. The system will function normally if the
trigger fuses are not replaced . However , phase indication will
not be provided.
Use only Ferraz-Shawmut Type Tl-600 trigger fuses in the
indicator, Siemens Part 72-1 40-31 7-001 .
Key I nterlock System
Each fuse carriage is equipped with an integral key-operated
interlock for installation in a specific compartment. Interlocks
prevent racking the fuse carriage in or out of the CONNECT
position if its associated circuit breaker is not in its locked
open position.
Once the circuit breaker is open
disconnected position, with the breaker trip bar depressed
the key in the circuit breaker compartment can
lowering the locking bar to prevent closing the circuit breaker.
The key can then be removed from the circuit breaker lock
and transferred to the lock on the fuse carriage. The fuse
carriage lock operates the slide interlock cover over the
racking screw of the fuse carriage. Once the racking screw is
exposed, the fuse carriage can be racked in or out usin g the
racking handle. The key is retained in the lock when the fuse
carriage is between the TEST and CONNECT positions.
elec­
present inside trigger fuse
CONNECT
carriage is in the
and racked to its
be
rotated,
Fi g u re 1 4 . Key Interlock Located i n C i rc u i t B reaker
Comrartment.
Figure 1 5. Fuse Carriage Key Interlock
24