GE Industrial Solutions Galaxy Vector Controller GCM3 - Manual (Page 47)

Galaxy Vector Controller GCM2, GCM3
Issue 4 January 2008 Operation 3 - 13
the ac service, especially useful in avoiding loading down an
emergency generator with an inrush surge.
The Reserve Operation (RO) engine signal (closure, available
only on the BLJ3 board) notifies the Vector that a backup engine
is supplying stable ac power to the rectifiers. A certain number
of rectifiers are then started in sequence. The number of
rectifiers which should be on when the engine is in use is
configurable. Refer to Section 4 for details. The number of ON
rectifiers is usually determined by the capacity of the engine.
When a rectifier reports an ACF to the Vector, it places that
rectifier into standby. As rectifiers report good ac, they are
turned on at 1 second intervals. When the controller senses the
RO signal, it pauses 10 seconds and starts the configured number
of rectifiers at 1 second intervals.
While RO is active, the Vector maintains the configured number
of rectifiers on. When RO retires, the Vector turns the remaining
rectifiers on at 1 second interval.
Shunt Types and Sizes
The Vector provides three separate methods and up to two
separate shunt signals for use in determining the plant current to
display. The access connections to the 2 shunt signals are on the
BLJ3 board SH1+/- and SH2+/- as shown in Figure 2-6, or on
the BTJ2/BTJ3 J21 plug as shown in Table 2-M. These signals
shall be a maximum of 50 mV signals that can represent a range
of 0-9999 amps. Refer to the configuration section of this
manual for additional details.
Float Mode Controls and Thresholds
Float mode is the default mode of operation and is active if the
Boost mode is not active. Plant voltage, while in Float mode, is
determined by the configuration parameter System Float Set
Point (FSP), and may be adjusted by the Battery Thermal
Compensation feature, if it is enabled. There is no individual
adjustment of plant rectifiers in this digital serial bus interface
arrangement. Load share among plant rectifiers is automatic in
all system modes and takes effect within several seconds of a
new rectifier being added to the bus and turned on.
The FSP chosen should correspond to the battery type used and
the battery manufacturer’s recommendations. For example,
Lineage Power KS20472 Round Cell (flooded) battery floats at
2.17 volts per cell (VPC). A 12 cell, 24V plant would therefore