APPENDIX F
93
OPERATING CHARGERS WITH LOAD SHARING
Restore external power connections to the battery chargers, and restart according to the
normal procedure in the AT Series Battery Charger Operating and Service Instructions. After the
chargers restart, the Primary charger attempts to establish communication with the Secondary. If
communication is successful, the chargers behave as follows:
•
The Primary charger displays the message
LS P
(Load Share, Primary) on the front panel,
alternating with the normal display of output voltage and current.
•
The secondary charger displays the message
LS S
(Load Share, Secondary) on the front
panel, alternating with the normal display of output voltage and current.
•
The Primary charger controls all voltage settings for both chargers. You may adjust any
voltage (float, equalize, alarm settings, etc.) at the front panel of the Primary charger. The
front panel of the Secondary charger won't allow any settings to be changed.
•
If one charger loses ac power (or is turned off), the remaining charger returns to
independent operation, whether it was originally the Primary or Secondary. For this reason,
it is important to set up both chargers initially for the same operating voltages. If an alarm
condition occurs, both chargers revert to independent operation for the duration of the
alarm.
•
In the event of a fault in the interconnection, or any other problem with communication, the
chargers return to independent operation, and the front panel on each charger displays the
message
E 14
, indicating the fault.
•
There is a delay of up to 4 seconds for chargers to establish forced load sharing
communication. If communication is broken (or power is lost for one charger), there is up
to a 4 second delay for the other charger to resume independent operation.
•
If you need to interchange the Primary and Secondary chargers, simply reverse the
interconnection cable.
•
The presence of the interconnection cable (and a good interconnection) forces the two
chargers into load sharing. Controlling load sharing from the front panel is neither
necessary nor possible.
WHEN TEMPERATURE COMPENSATION IS INSTALLED
•
The AT Series forced load sharing feature is compatible with the external tempco probe
accessory. However, only tempco for the Primary charger is active. If you interchange the
Primary and Secondary chargers, or discontinue load sharing, be sure to check that both
temperature compensation probes are working properly.
TROUBLE SHOOTING
If the AT Series Forced Load Sharing option is installed, but the output currents of the
chargers are unequal, refer to the following table.
PROBABLE
CAUSE
RECOMMENDED ACTION
1. Connection cable
missing or installed
incorrectly.
2. Incorrect connections
to ac power sources.
3. Defective or improper
Main Control circuit
board A1
1. Ensure that the interconnection signal cable assembly is properly
installed, and that the connector for the
Secondary
charger has the
jumper as described at the top of page 3.
2. Ensure that both chargers are connected to the same ac supply
and that source phase rotation is the same for both chargers.
3. Replace the Main Control circuit board in one charger at a time,
noting system requirements, to restore correct load sharing
operation.
Summary of Contents for AT30 SERIES
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