Siemens GMSG Instruction Manual page 16

Vacuum interrupter/operator
Shown with outer-phase barriers removed
Figure 10: Upper and lower primary disconnects
16
Phase barriers
Figure 11: Type GMSG vacuum circuit
breaker on page 17 is a rear view of a type
GMSG vacuum circuit breaker that shows
the outer-phase (phase-to-ground)
barriers. Interphase barriers are not
standard but may be provided as an
option. These glass-polyester insulating
barriers are attached to the circuit breaker
frame and provide suitable electrical
insulation between the vacuum-interrupter
primary circuits and the housing.
Stored-energy operating mechanism
The stored-energy operating mechanism
of the type GMSG vacuum circuit breaker is
an integrated arrangement of springs,
solenoids and mechanical devices
designed to provide a number of critical
functions. The energy necessary to close
and open (trip) the contacts of the vacuum
interrupters is stored in powerful tripping
and closing springs. The closing springs
are normally charged automatically, but
there are provisions for manual charging.
The operating mechanism that controls
charging, closing and tripping functions is
fully trip-free. Trip-free requires that the
tripping function prevail over the closing
function as specified in ANSI/IEEE
C37.04-1999, clause 6.9. The operation of
the stored-energy mechanism will be
discussed later in this section.
The vacuum circuit breaker consists of two
sub-assemblies. The "interrupter/operator"
module is a unitized assembly of the three
vacuum interrupters, primary insulators
and operating mechanism. The second
module, the "vehicle", is the supporting
drawout-structure module for the
operating mechanism.
The vehicle provides primary-stud
extensions, closed circuit breaker racking
interlocks, closing spring discharge feature
and other requirements needed to ensure
safe and reliable use during racking and
during operation. These two sub-
assemblies will be separately described.
Interrupter/operator module
The interrupter/operator module consists
of the three poles, each with its vacuum
interrupter and primary insulators,
mounted on the common motor or hand-
charged spring-stored energy-operating-
mechanism housing. This module is shown
in Figure 12: Interrupting/operating
mechanism module.