105
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7. Operation of the switchgear
Earthing switch
The earthing switch has a snap closing
mechanism which is independent of the rotation
of the drive shaft. An earthing switch allocated to
a circuit-breaker is only enabled for switching
when withdrawable part is in the test /
disconnected position or removed from the
switchgear panel. Only turn earthing switches on
when the doors are closed.
Manual opening and closing:
Press slide 2 (Figure 174) downwards onto the
operating lever recess socket. (When the switch is
closed, it is already in this position!)
Caution:
If the operation is prevented, do not force the
interlock and check that the operation sequence
is correct. Check the cable compartment door is
closed and door handle is in its final closed
position. Fit operating lever 1 (Figure 175) onto
hexagonal shaft 1 (Figure 174), which is now
released for operation. If there is blocking spike
which causes that operating lever cannot be
fitted, follow the procedure of setting the
control blocking of earthing switch described in
"6.4 Procedure for setting-up the doors"
Note:
Position operating lever 1 (Figure 175) to point up
or down on the hexagonal shaft so that there is
sufficient room for movement of the operating
lever even if space is limited at the sides.
• Turn the lever clockwise through approx. 180°
until the stop is reached to close the earthing
switch, or anti-clockwise until the stop is
reached to open the earthing switch
• Observe the mechanical/electrical switch
position indicator
• Remove operating lever. Slide 2 (Figure 174)
remains open if the earthing switch is in the
closed position. Make sure that the operating
lever is turned right up to the stop in the
opening process, to ensure that the earthing
switch is in its defined limit position. The
manual operating mechanism can also be
fitted with a locking magnet.
Opening and closing with motor operator: The
earthing switch can also be fitted with a motor
operator. Briefly operate the electrical control for
opening or closing. The earthing switch is then
switched automatically into the opposite
position.
Emergency manual operation:
If a fault should occur in the motor operator, the
earthing switch can be switched to emergency
manual operation with lever, in a similar way to
manually operated earthing switches.
Caution:
• During emergency manual operation of a
motor-operated earthing switch, the
interlock is not functional!
• On emergency manual operation, coupling
with the motor operator is automatically
released. To disengage the coupling to the
motor operator, first turn the lever further
in the pre-selected direction up to the
relative stop (turning through a small
angle). On the next operation with the
motor operator after its function has been
restored, the coupling automatically re-
engages.
Note:
The lever may only be fitted temporarily to carry
out an emergency manual switching operation.
The power to the motor operator must be
switched off for the duration of any breakdown.
Busbar earthing switch
To earth the busbars, earthing switches are also
used. Their operating mechanism is identical to
that of the branch earthing switches. The
conditions for panel to panel interlocking of the
busbar earthing switches ("4.4 Interlock/
protection against incorrect operation").
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