GE Industrial Solutions Galaxy Vector Controller GCM3 - Manual (Page 36)

Galaxy Vector Controller GCM2, GCM3
3 - 2 Operation Issue 4 January 2008
Following the restoration of ac power after a battery discharge of
significant depth, this alarm remains active for some time during
the recharge period, until the batteries have recharged to a level
which allows the plant voltage to rise above the BD threshold.
BD threshold default is set at 25.54V standard (Flexent 25.0V)
in 24V systems and 51.1V in 48V systems with slope thermal
compensation disabled. In systems with slope thermal
compensation, the BD threshold should be 0.5V below the slope
upper temperature voltage for 24V systems, and 1.0V below the
slope upper temperature voltage for 48V systems. The slope
upper temperature equals:
Float Set Point - (number of cells) · E · (F-D)
See Figure 3-1 for system settings E, F, and D
These levels generally avoid nuisance alarms from transient
conditions yet provide alarm indications early in a true BD
event, so that sufficient time is provided for maintenance
personnel to respond before battery reserve is exhausted. VLV
should be activated towards the end of the battery reserve
voltage to indicate a critical service condition.