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4. Panel design and equipment
Withdrawable parts
1. Withdrawable circuit-breakers
The withdrawable circuit-breaker forms a
complete module consisting of the vacuum
circuit-breakers type VD4 or VM1, SF6 circuit-
breaker type HD4 the withdrawable assembly,
isolated contact arm with contact system and
control wiring plug.
The withdrawable assembly and the circuit-
breaker are coupled via a multi-pole control
wiring plug connector.
The withdrawable assembly establishes the
mechanical connection between the panel and
the circuit-breaker. The fixed part is connected to
the panel by a forked connection, which is form
coded on both sides. The moving part with the
circuit-breaker is moved either manually or by a
motor by means of a spindle, between the service
or test / disconnected positions with the front
doors closed. Service and test / disconnected
positions are set precisely by means of auxiliary
switches, which register the final position
reached and the angular position of the spindle.
The earthing connection between the
withdrawable part and the panel is established by
its rollers and travel rails which are bolted onto
the panel.
Withdrawable parts of the same design and
electrical parameters are interchangeable. In the
case where the withdrawable parts have the same
dimensions, but different electrical parameters,
the control wiring plug coding prevents any
incorrect connections between the withdrawable
part and the panel.
2. Withdrawable contactors
In place of the circuit-breaker type, the
withdrawable part can also be fitted with the
vacuum contactor. Vacuum contactor is fitted
with MV fuses and can be used for rated voltage
up to 12 kV. All the data stated in this chapter for
circuit-breakers also applies to the contactors.
3. Other withdrawable parts
The withdrawable part can also be fitted with the
following trucks:
• Metering voltage transformers truck with
fuses
• Earthing truck without making capacity (for
main busbar system and power cables)
• Earthing truck with making capacity (for
main busbar system and power cables)
• Power cable testing truck
• Isolation truck
• Isolation truck with fuses
• Shutter lifting truck
Figure 16: Withdrawable part with circuit-breaker, type
VD4, operating mechanism side
1 Withdrawable assembly
Figure 17: Withdrawable assembly for circuit-breaker,
with auxiliary switches
1 Test position indicator
2 Service position indicator
3 Square spigot
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