ABB SGF, Instruction Manual

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5.3 Earthing Switch
Operating mechanism :-
The operating mechanism (77) of the earthing switch transfers the operating energy via the operating
rod (71) to the earthing-switch shaft (337). The tubular contact arm (23) swivels up (ON) or down
(OFF). During switching-on, the contact fingers (20) glide over the earthing contact (18). In the ON end
position, they are in preloaded contact against the stop.
Earthing connection :-
The earthing connection (79) connects the tubular contact are (23) to the earthed sectional-steel base
frame (221) of the disconnector.
5.4 Interlocking
The disconnector and the earthing switch can be interlocked according to the following principle :
• Disconnector only ON when earthing switch OFF
• Earthing switch only ON when disconnector OFF
Interlocking is mechanical and/or electrical, depending on the version
Note :
Mechanical interlocks between disconnector and earthing switch are fitted at the factory.
Retrofitting is not possible.
Figure 6 :
Mode of operation of earthing switch (example : 3-pole in parallel arrangement)
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