8 Chapter 1 Overview
Liebert NXC 30kVA And 40kVA UPS User Manual
When the battery has small current discharge for a long time, the battery is over discharged and even has
unrecoverable damage, thus setting a battery discharge time to protect the battery is essential. The limit of time setting
shall be configured by service engineer through the Emerson setting software.
9. Maximum boost charge protection time
To protect against the battery overcharge damage caused by long time boost charge, a protect time setting is essential.
The limit of time setting shall be configured by service engineer through the Emerson setting software.
1.5.2 Advanced Function
The UPS provides battery maintenance test function. At periodic intervals, 20% of the rated capacity of the battery will
be discharged automatically, and the actual three-phase load must exceed 20% of the nominal UPS capacity. If the
load is less than 20%, the automatic discharge cannot be executed. The periodic interval can be set from 30 to 360
days. The battery maintenance test function can be disabled through the Emerson setting software.
Conditions: Battery at float charge for at least 5h, load equal to 20% ~ 100% of rated UPS capacity.
Trigger: Automatically, or manually through the command of battery maintenance test in LCD.
Interval: 30 ~ 360 days (default setting: 60 days).
The UPS also provides battery capacity self-test function: Periodically test the battery activity, test the battery residual
capacity, judge the battery quality, and then provide the corresponding measures. The capacity self-test is started by
the user through the operator control and display panel. During the capacity self-test, the battery will continuously
discharge to the battery undervoltage shutdown threshold. After the self-test is finished, the system will update the
battery curve table. The capacity self-test command is valid only one time, without any memory. During the capacity
self-test, if the battery maintenance requirement is satisfied, the system will generate audible/visual alarm and give
corresponding records.
Conditions: System load rate within 20% ~ 100%, battery float charge at least 5h, and generator not connected; the
current system is in float charge state.
Trigger: Start up through the LCD.
Note:
1. The battery will continuously discharge to the battery undervoltage shutdown threshold, then the battery transfer to
the charging state. When the capacity self-test is finished, the system will update the battery curve table.
2. The user can manually stop the capacity self-test operation through the LCD.
1.5.3 Battery Temperature Compensation
The UPS system has battery charge temperature compensation function. When the ambient temperature is increased,
the DC bus voltage (which charges the battery) will be reduced correspondingly to provide optimal charging voltage for
the battery, thus prolonging the battery service life time.
This function must be used together with the Emerson battery temperature detection device (a standard option).
1.6 Battery Protection
The following battery protection functions are set by the service engineer through the Emerson setting software.
Battery low pre-warning
The battery low pre-warning occurs before the EOD. After this pre-warning, the battery should have the capacity for
three remaining minutes discharging with full load. The time can be configured from 3min to 60min.
EOD protection
When the battery voltage drops to the EOD voltage, the battery converter shuts down automatically. The EOD voltage
is adjustable from 1.6V/cell to 1.9V/cell (VRLA).
BCB alarm
The BCB alarm occurs when the external BCB opens, if you select the Emerson BCB (optional).
The external battery connects to the UPS through the BCB. The BCB is manually closed and tripped by the UPS
control circuit.
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