100
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7. Operation of the switchgear
Circuit-breaker - type VD4 and VD4G
Charging the stored energy spring system:
• Charging of the circuit-breaker is carried out
automatically by the charging motor. If the
charging motor should fail, the charging
procedure can be carried out or completed
manually.
• If mechanical charging is necessary open the
door with the withdrawable part in the test
position. The lever for loading the closing
spring in the manual mode is built into the
operating mechanism. The spring is loaded
by repeatedly lowering the lever with linear
movements until the yellow indicator appears
to show that loading is complete.
• Note: on request, the closing spring loading
device for withdrawable circuit breakers for
UniGear switchgear can be supplied with the
lever outside the operating mechanism and a
rotary loading movement. This rotary loading
device allows the closing spring to be loaded
with the switchgear door closed.
• When the charged condition is reached, the
charging mechanism is automatically
disengaged, and any further strokes of the
lever have no effect (Figure 166). Pumping is
effective if the lever is moved over an angle
of 90°.
Opening and closing the circuit-breaker:
• Opening and closing operations with the
withdrawable part in the service position
should only be performed with the door
closed.
• Operate the local or remote electrical control.
• Observe the switch position indicator. The
switching operation counter for the circuit-
breaker automatically increases by one unit
with each operating cycle. An additional
control mechanism fitted in the door of the
circuit-breaker compartment enables
mechanical operation of the circuit-breaker
with the door closed and with the
withdrawable part in either position.
• Press the relevant mechanical pushbutton,
having previously turned knob anti-clockwise
to the stop if the withdrawable part is in the
service position.
• Observe the switch position indicator. For
further details regarding operations and
maintenance of VD4 circuit-breakers, see
instruction manuals.
VD4G is vacuum circuit-breaker for generator
(GCB) applications.
VD4G is suitable for the small power plants as
well as for industrial, oil and gas applications in
which generators are connected to the MV
distribution of the plant. Operation of VD4G is
identical to standard VD4 circuit breaker.
VD4G must be used only in the dedicated panel
version.
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