Siemens 8DJH Series - Operating mechanisms for the three-position switch

500-8067.9 * INSTALLATION AND OPERATING INSTRUCTIONS 8DJH * Revision 03 13
Description
Mode of operation The operating shaft forms one unit together with the three contact blades.
Due to the arrangement of the fixed contacts (earth - busbar), it is not necessary to
interlock the CLOSE and EARTHING functions.
Closing operation During the closing operation, the operating shaft with the moving contact blades
changes from the “OPEN” to the “CLOSED” position.
The force of the spring-operated mechanism ensures a high closing speed and
a reliable connection of the main circuit.
Opening operation During the opening operation, the arc is caused to rotate by the arc-suppression system,
thus preventing the development of a fixed root. This very effective arc extinction
provides short arcing times. The isolating distance in gas established after opening
satisfies the conditions for isolating distances according to IEC/EN 60 265-1 /
VDE 0671-102 and IEC/EN 62 271-1 / VDE 0671-1.
Earthing operation The "EARTHING" operation is implemented by the turning movement of the operating
lever (rotation, if required) from the "OPEN" to the "EARTHED" position.
Operating mechanisms for the three-position switch
Common features • Mechanical endurance of more than 1000 operating cycles
• Manual operation with the help of a slip-on operating lever
• Option: Motor operation of the disconnecting function
• Control board with accordingly cut-out switching gate prevents the three-position
switch-disconnector from being switched directly from the CLOSED via the OPEN to
the EARTHED position.
• Two separate actuating openings are provided for unambiguous selection of either
the load-break function or make-proof earthing.
• Operation via rotary movement, operating direction according to IEC/EN 60 447
(VDN/VDEW recommendation).
The switching movements are performed independently of the operating speed.
Features of spring-
operated/stored-energy
mechanism
During the charging process, the closing and opening springs are charged. This ensures
that the switch-disconnector/fuse combination can switch off all types of faults reliably
even during closing.
Closing and opening is done via pushbuttons after removing the operating lever, and is
therefore identical with the operation of circuit-breaker operating mechanisms.
An energy store is available for tripping by means of an operating HV HRC fuse or
via a shunt release (f-release).
After the HV HRC fuse has tripped, a red crossbar appears on the "fuse tripped" indicator.
Manual operation for the EARTHING function with the help of a slip-on operating lever.
Design The three-position switch-disconnector is operated through a gas-tight welded bushing
at the front of the switchgear vessel.
Assignment of operating mechanism type of three-position switch to panel types
Panel type R, L T
Function Switch-disconnector (R) Earthing switch Switch-disconnector Earthing switch
Disconnector (L)
Type of operating
mechanism
Spring-operated Spring-operated Stored-energy Spring-operated
Operation Manual Manual Manual Manual
Motor (option) Motor (option)