ELTEX Terrabox TCB030, Руководство по эксплуатации

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BA-en-4003-2005_TUE30
4.3 Operation with 2 ground contactors, BIG-BAGgrounding
During operation with 2 ground contactors, it is not only the ground link of
the BIG-BAG which is being monitored, but also the conductivity of the
BIG-BAG. Note that both ground contactors are connected to two different
grounding points of the BIG-BAG. The intrinsically safe measuring current
of the ground monitoring system flows from clamp 1 through the fabric of
the BIG-BAG, with the conductivity of the BIG-BAG to be grounded being
monitored at the same time. In this operating mode, ground contactor 1 is
connected to the measuring current source, while ground contactor 2 is
connected to ground potential.
Operating mode:
4.3.1 Before connecting the two ground contactors, the BIG-BAG
has no connection to ground potential
The connection is made after both ground contactors have been
connected to the grounding clips of the BIG-BAG. The intrinsically safe
measuring current flows from ground contactor 1 through the BIG-BAG
fabric to ground contactor 2, and via ground contactor 2 to ground
potential.
4.3.2 Before connecting the two ground contactors, the BIG-BAG is
already connected to ground potential
The connection is made as soon as ground contactor 1 is connected to
the BIG-BAG. The intrinsically safe measuring current flows from ground
contactor 1 through the fabric of the BIG-BAG via the existing ground
contact to ground potential. A ground link of the BIG-BAG also exists in
this case, with the effect that filling can proceed without hazard in this
case. The interruption of the existing ground link results in the interruption
of the intrinsically safe circuit, and filling would stop. For safety reasons,
both ground contactors should always be connected because no
assurance can be given that an existing ground link can be upheld
throughout the entire filling process.
It makes sense in this case to specify in an appropriate work instruction to
first connect ground contactor 2 and then ground contactor 1. The
connection is therefore made only after both ground contactors have been
connected.