VACUUM CIRCUIT BREAKER
Operation & Maintenance Manual
04
3.2.4 - Opening
The circuit breaker can be opened by electrical trip or by the
manual open pushbutton. The close / trip latch located behind
the roller is displaced and the contact springs and opening
springs rotate the secondary shaft clockwise to fully open the
circuit breaker and indicating Open .
3.3 - Operation of Control Circuit
3.3.1 - Closing Spring Charging Operation
Figure 3.4a shows the control circuit of the circuit breaker when
the closing spring is in the charged state and the circuit breaker
is open. When the closing spring is discharged it rotates the
mechanism main shaft with its switch operating cam and
LS
is
switched on. In this state when M1 & M2 is connected to an
auxiliary supply the motor automatically recharges the closing
spring and
LS
is switched off (spring charging time <10secs).
During this closing operation, the b contact of the auxiliary
switch is turned off, and also the energised relay Y opens it
contact Yb to complete the pumping prevention circuit. Thus, if
the same close signal stays on, Yb remains open and prevents
reclosing of the circuit breaker. The closing circuit is also provided
with contact Xb from the control relay which prevents the spring
release coil CC being energised while the closing spring is being
charged.
3.3.2 - Opening Operation
The tripping circuit is formed by
a1-TC
. When the circuit breaker
is closed and the external operating switch is turned to TRIP the
trip coil
TC
is energised and the circuit breaker opens in<60ms.
During the open operation the contact of the auxiliary switch is
turned off de-energising the trip coil
TC
.
Note: the TC terminals are used to monitor the trip circuit.
3.4 - Figures
Figure 3.4 a - Front View of The Vacuum Circuit Breaker
Figure 3.4 b - Side View of Gas Tank and Mechanism
Pressure Gauge
Indication
Socket for
charging Handle
Trip Button
Closing Button
