Schaefer Series C/B 3500 - Manual (Page 9)

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Technical Notes Technical Notes Operational Characteristics
Parallel operation
Single output modules of the same voltage / power rating
can operate in parallel under specific conditions. The output
voltage can be carefully adjusted to be near identical. When
there is sufficient loading on the combined output, all units
will be active and supply the load. The load demand must
be significant enough for the multiple units to deliver output
current.
Redundant operation
The inclusion of the option “dd” (decoupling diode) on the
output of the units will permit parallel operation, where
the inability to provide output from one unit will not have
a negative effect on the load provision. The decoupling
diode will also result in a load regulation value, which, as
a percentage of the output voltage, will be unit / output
dependent. In terms of calibration the same criteria follow as
for parallel operation.
DC or
AC
=
=
DC or
AC
=
=
DC or
AC
DC or
AC
The following technical notes contain impor-
tant information about various operating pos-
sibilities and circuitries as well as instructions
that should be followed during installation
etc. For further information please contact the
SCHAEFR Team.
Parallel / Redundant System 125
AC or DC input 127
DC output 128
AC output 129
DC output voltage stabilization 130
Mounting & Installation 131
Connectors 132
Basic Topologies 133
Parallel / Redundant System
Technical Notes
Balanced current operation
The inclusion of the option “cs” (current sharing) allows
for parallel operation with a significant degree of current
balancing. The communication between the units allows for
a voltage setting correction, which in turn shall equate to an
automatic current sharing (balancing) on the outputs. The
tolerance of such balancing is module dependent. In terms of
calibration the same criteria follow as for parallel operation.
Redundant balanced operation
The inclusion of both, the “cs” and “dd” option results in an
optimized balanced current provision while being de-coupled
from each other. A connected module, who is not supplying
an output voltage, will influence the load voltage. The voltage
may be reduced by up to 7 %. In terms of calibration the same
criteria follow as for parallel operation.
Fault tolerant operation
The inclusion of “csi” (current sharing interrupt), “cs” and
“dd” is the optimum set up for a fault tolerant application.
“csi” will effect the removal of the “cs” signal from the load
voltage common connection. Should there be an instance
where a unit is not supplying the load, then the effect of its
current sharing signal is removed, and the load voltage is
unaffected by this condition. In terms of calibration the same
criteria follow as for parallel operation.
CS
DC or
AC
=
CS
DC or
AC
=
CS
CS
DC or
AC
=
CS
DC or
AC
=
CS
DC or
AC
=
CS
CSi
DC or
AC
=
CS
CSi
CS