Fagor DDS APS-24, Hardware Manual

Page: 237 / 406

   Power line connection
6.
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DDS
HARDWARE
IT diagram
Distribution diagram that has no direct connection to ground and the
conductive parts of the installation are connected to ground.
With IT type distribution diagrams, the differential breaker is used assuming
that the capacitance of mains with respect to ground is large enough to
ensure that a minimum fault current flows with the same magnitude as that
of the operating differential current assigned. Otherwise, its use is not
necessary.
See figure F. H6/6 for properly installing the DDS system with an IT type
distribution diagram.
F. H6/6
IT type distribution diagram.
DDS
L1
L2
L3
SECONDARY
WINDING OF THE
LINE TRANSFORMER
OF THE PLANT
DIFFERENTIAL
BREAKER
MAINS
FILTER
L1
L2
L3
DDS
DIFFERENTIAL
BREAKER
SECONDARY
WINDING OF THE
LINE TRANSFORMER
OF THE PLANT
MAINS
FILTER
IT diagram
MANDATORY. With an IT distribution diagram, always install the DDS
system to mains through an isolating transformer.
INFORMATION. Note that with an IT type distribution diagram, mains can also
be controlled through an isolation watching device. Both protection
measurements are compatible with each other.
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