Siemens GMSG Instruction Manual page 35

Figure 31: Closed circuit breaker
interlock mechanism in stored-
energy mechanism on page 34
shows the operating mechanism
detail components which establish a
spring dump condition as the spring
dump/trip-free interlock is actuated
by the spring dump and trip-free
cam profiles on the racking
mechanism. The rising plunger
raises a lever attached to the base of
the operating mechanism enclosure.
This lever raises the trip-free
pushrod, which raises the closing
spring release cam. This blocks
closing of the circuit breaker while
the circuit breaker is being racked.
C. Trip-free interlock position -
mechanical interlock
In order to prevent the motor-
charging circuit from "making and
breaking" as the circuit breaker and
cubicle secondary disconnects make
or break physical contact, an
electrical switch is provided.
IThis switch is mounted in the line of
action taken by the trip-free
interlock plunger that follows the
racking-mechanism cam and is
elevated at all times while the circuit
breaker is in the drawout
compartment except when in the
TEST or CONNECT positions.
A striker plate, integral with the trip-
free interlock plunger, engages and
operates (opens) the switch when
the plunger is in an elevated position
blocking spring-charging motor
operation. The switch is closed when
the circuit breaker occupies the TEST
or CONNECT position, allowing the
charging motor to operate
automatically.
Vacuum interrupter/operator
35