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7.3. Interlocks
7.3.1. Interlocks / protection against malfunction (for withdrawable circuit-breakers for UniGear
ZS1 type switchgear and PowerCube modules)
A series of interlocks is provided to prevent incorrect operations and/or malfunctions. The inter-
locks are the following:
• the withdrawable truck can only be moved from the test/isolated position to the service position
(and vice versa) if the circuit-breaker is open (this means that first of all the circuit-breaker must
be opened).
• the circuit-breaker can be closed if the withdrawable truck is exactly in the defined test position
or in the service position (electric interlock).
• the circuit-breaker can be opened manually in the service or test position when it is not pow-
ered, but it cannot be closed.
• the switchgear is provided with devices which only allow connection and disconnection of the
plug connector (1) (fig. 10) in the test/isolation position.
Any detailed information regarding additional interlocks, e.g. with the earthing switch operating
mechanism, is given in the specific order documentation.
7.3.2. Interlocks in the case where withdrawable trucks are used UniGear ZS1 type switch-
gear and PowerCube modules
1) There is the possibility of configuring a binary input and relative function to allow the lock on
circuit-breaker closing when a voltage of 24 V - 240 V a.c./d.c. is applied to the input (electric
closing lock).
2) The eVM1/P circuit-breaker can only be closed when the withdrawable truck is in the test or
service position. In intermediate positions the closing lock voltage is cut off by the auxiliary
contacts of the truck.
3) A mechanical interlock positioned on the withdrawable truck prevents a closed circuit-breaker
being moved from the test position to the service position.
Fig. 10
1
2
15
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