Theoryof Operation 17
Operation After End-of-Discharge
Thebattery time screen displayedon the control panel enables you to estimate whenbattery shutdown will occur.
Youwill have enough time to energize an alternateAC power source or to initiate an orderly shutdown of the
criticalload. If the battery plant dischargesto the shutdown point during an outage, the UPS automaticallydis-
connectsthe load, the AC input, and the battery.After AC input power is restored, the rectifier can be manually
restarted by the user.
Battery Disconnect
Theexternal module battery disconnect (MBD) circuit breakeris used to isolate the UPS module from the bat-
teryduring maintenance and to automatically disconnect the batteryfrom the inverter at the end of battery dis-
charge.The MBD circuit breaker can be opened or tripped automatically,from the control panel, or manually. It
mustbe closed manually.
Battery Charge Current Limiting
Thebattery recharge current, after a battery discharge, islimited to between 1 and 25% (adjustable) of the full
loaddischarge current. An additional (optional) charge-limitingcircuit can be activated by external dry contact
closure(field supplied) for use when operating on a back-up generator.These two levels of control regulate the
amountof current that flows from the power source to the battery whilethe battery is recharging.
Thebattery charge current limit is factory set at 10% for normal operationand at 1% for alternate power source
rechargeoperation.
Battery Equalize Charge Circuit
Thebattery equalize charge feature can be manually initiated or it can be programmedto operate automatically.
Eithercan be selected from the battery equalize screen displayed on the controlpanel.
Thebattery equalizing charge circuit increasesthe rectifier/charger outputvoltage to charge the battery any time
thereis a power outage of 30 seconds or longer.The equalizing voltage is slightly higher than thefloat voltage.
Thisdecreases the time required to recharge thebattery.
NOTE
Donot use equalize charging with valve-regulatedlead-acid batteries
Consultthe battery manufacturer's manual for specificinformation about equalize
charging.
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