Siemens GMSG Instruction Manual page 32

Vacuum interrupter/operator
32
Circuit breaker handling wheels
The type GMSG vacuum circuit breaker is
designed for easy movement into and out
of the metal-clad switchgear assembly.
A section of indoor or Shelter-Clad
switchgear does not require a transfer
truck or lifting truck for handling of the
circuit breaker when all circuit breakers are
located at floor level. Once the circuit
breaker is racked out of the switchgear, the
unit can be pulled using the handles on
the front of the circuit breaker. The circuit
breaker will roll on its bottom four wheels.
When circuit breakers are located above
floor level, handling of the circuit breakers
requires the use of a lifting device or a
crane with a lift sling.
Racking mechanism
Figure 29: Circuit breaker compartment up
to 50 kA shown on page 30 shows the
racking mechanism in the switchgear used
to move the circuit breaker among the
DISCONNECT, TEST and CONNECT
positions. This mechanism contains a
circuit breaker racking-block that mates
with the bottom of the circuit breaker
housing, and locks the circuit breaker to
the racking mechanism during in and out
movement.
A racking crank (refer to Figure 2: Type
GMSG vacuum circuit breaker racking on
page 11) mates to the square shaft of the
racking mechanism. Clockwise rotation of
the crank moves the circuit breaker into
the switchgear, and counterclockwise
rotation removes it.
The racking and trip-free interlocks provide
several essential functions.
1. They prevent racking a CLOSED circuit
breaker into or out of the switchgear
assembly.
2. They discharge the closing springs
whenever the circuit breaker is inserted
into or withdrawn from the switchgear.
3. They prevent closing of the circuit
breaker unless it is in either the TEST or
CONNECT positions, and the racking
crank is not engaged.
The rating interlock prevents insertion of a
lower-rated circuit breaker into a cubicle
intended for a circuit breaker of higher
ratings, subject to the limitations detailed
in "Rating interlock".
Vehicle function and operational
interlocks
A type GMSG vacuum circuit breaker is
comprised mainly of the vacuum
interrupter/operator module fitted to a
vehicle. This vacuum interrupter/operator
module is an integral arrangement of
operating mechanism, dielectric system,
vacuum interrupters and means of
connecting the primary circuit. The vehicle
supports the vaccum interrupter/operator
module, providing mobility and fully
coordinated application in Siemens type
GM-SG or type GM-SG-AR switchgear.
Successful coordinated application of the
fully assembled type GMSG vacuum circuit
breaker is achieved through precise
alignment in fixtures during manufacture,
and important functional interlocking.
Alignment
All aspects of the circuit breaker structure
impacting alignment and
interchangeability are checked using
master fixtures at the factory. Field
adjustment will not normally be required.