Vehicle Description
Vehicle Function and Operational Interlocks
Type GER vacuum circuit breakers are comprised of the
interrupter/operator module fitted to a vehicle. This inter-
rupter/operator module is an integral arrangement of op-
erating mechanism, dielectric system, vacuum interrupt-
ers, and means of connecting the primary circuit. The ve-
hicle supports the interrupter/operator module, providing
mobility and fully coordinated application in GE Metal-Clad
type M26 and M36 switchgear.
This manual should be used jointly with the Circuit Breaker
Operator manual, SGIM-9918 (3AH) or SG-3398 (3AF).
Alignment
All aspects of the circuit breaker structure which impact
alignment and interchangeability are checked at the fac-
tory. Field adjustment will not normally be required, but
variations in existing switchgear may require field adjust-
ment.
Recommended Tools
• Racking Crank: Original circuit breaker racking crank
may be used.
Installing Circuit Breaker Module Into Compartment
Interlock
Trip-Free/Spring Dump Interlock
The Trip-Free/Spring Dump interlock is of primary
importance in the safe and effective operation of the type
GER Vertical Lift Replacement circuit breaker. This interlock
provides safety to both personnel and equipment during
the racking procedure, as it prevents the electrical or
manual closing and/or electrical spring charging of the
circuit breaker until the circuit breaker is in either the
Disconnect/Test position or the Connect position.
It is important to note the Trip-Free/Spring Dump interlock
on the type GER circuit breaker is functionally similar to
the original manufacturer’s interlock, however, there are
differences among the two interlocking systems which
must be discussed.
Hazardous voltages and high-speed
moving parts. Will cause death, serious
injury, and property damage.
De-energize before working on this equip-
ment.
Do not by-pass interlocks or otherwise make
interlocks inoperative.
4
Inoperative or by-passed interlocks will cause
death, serious personal injury and property
damage.
Mechanical and electrical interlocks are pro-
vided as integral components of this equip-
ment to ensure safe use. Interlocks must be
in operation at all times. Read this instruc-
tion manual. Know and understand correct
interlock function. Check interlock function
prior to inserting circuit breaker into
switchgear cubicle.
Differences
The original manufacturer’s trip-free and spring dump
interlocking is a two stage system. In this system, the
spring dump is accomplished in one stage, and occurs via
a ramp located on the left side of the cubicle working in
concert with a linkage system. The springs are dumped as
the circuit breaker is rolled in or out from the Disconnect
position as the circuit breaker linkage is actuated by the
cubicle mounted ramp.
The second stage of the original manufacturer’s system
addresses the trip-free condition of the circuit breaker. In
this system the circuit breaker is held trip-free during
racking via the trip roller located on the right side of the
circuit breaker, working in concert with the moveable cam
plate associated with the elevating mechanism. The circuit
breaker is held trip-free during racking as the trip roller is
displaced by the moveable cam.
Another distinct difference among the two systems is that
the original manufacturer’s circuit breaker must be
manually “tripped” (opened) prior to attempting to rack
the circuit breaker.
The trip-free/spring dump arrangement on the Siemens
type GER replacement circuit breaker is integrated into a
single stage interlocking system. Trip-free operation, spring
dump and circuit breaker “tripping” (opening) all result
from the single linkage arrangement operated by the trip-
free roller located on the right side of the circuit breaker,
which works in concert with the moveable car mounted in
the original switchgear cubicle. There is no spring dump
linkage located on the left side of the type GER circuit
breaker and manual tripping of the circuit breaker prior to
racking is not required as both of these functions occur
instantaneously with the initiator displaced by the
moveable cam in much the same manner as the original
manufacturer’s circuit breaker.
The function of the type GER circuit breaker trip-free/spring
dump interlocking will be discussed in greater detail.