GE Industrial Solutions CPS6000 - Manual (Page 140)

CPS6000 –48V Indoor/Outdoor Power Shelf
Issue 21 January 2008
140
Communication Failure
If the LVD board loses communication with the system controller, it will blink its LED in red
color. Note that during a battery on discharge event, the system controller signals the LVD
board to disconnect the batteries from the system once the battery strings have discharged to
the threshold voltage set by the user. This command is not possible during a communication
failure. If communication is lost during this event, the LVD boards will disconnect at the
backup disconnect voltage of 35V +/- 1V.
Similarly, when the utility supply source returns, the rectifiers will power up and the output
bus voltage will rise to the Float Set Point set by the user. Once the output voltage crosses the
reconnect threshold also set by the user, the system controller commands the LVD contactor
to close and connect the batteries to the bus voltage. During communication loss with the
controller, this command will not be possible. In this case, the LVD contactor will reconnect
at the backup reconnect voltage of 48V +/- 1V.
Reverse Battery Protection
This feature prevents closure of the LVD contactors if the QS872A detects the battery strings
are connected in reverse polarity.
Note that the system will prevent contactor closure only if it detects improper polarity. If no
batteries are connected to the system and the CPS6000 system is powered up, the QS872A
will close the contactors and present the output bus voltage at the battery terminals.
If an external disconnect switch is being used to take battery strings off-line for replacement,
care must be taken to ensure battery connections are correct at the switch. This is because the
contactors remain closed when an external disconnect switch is used to disconnect the
batteries from the bus. If the batteries are reconnected in reverse polarity, closing the switch
will result in the batteries being connected to the bus in reverse polarity.