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3.2.7 Alarm Limit Settings Screen
Go to the Master Menu and move the highlighted cursor to LIMIT SETTINGS. Press the Select pad
and the Limit Settings screen is displayed.
The Alarm Limit Settings screen has Security Access to enable an authorized Liebert field-service
engineer to adjust the UPS system alarm limit settings.
Figure 40 Module alarm limit settings screen
Overload Alarm (SCC and Modules): This alarm setting initiates an alarm message on the display
screen warning the operator that the UPS system output current has exceeded the specified limit.
This condition only activates an alarm. The UPS does not shut down, but a separate control circuit
will transfer the critical load to bypass if the current and time of the overload condition exceeds sys-
tem capability.
DC Overvoltage (Modules Only): This setting limits the maximum permitted level of the DC bus
voltage. When this setting is exceeded, an alarm indication appears on the module display screen. The
UPS module is taken off-line (the module output circuit breaker is tripped open) and the input and
battery circuit breakers trip open.
Battery Discharging (Modules Only): When the battery voltage on the DC bus falls below this
limit for 5 seconds, a Battery Discharging alarm message is displayed on the module screen. This
means that the battery is discharging due to an input voltage sag or interruption or a module output
overload.
Low Battery (Modules Only): While the battery is discharging, this alarm warns the operator that
the Battery Shutdown level is approaching. This is generally set for a reserve time of approximately 5
minutes (typically 10 volts above the 60-Minute Battery Shutdown voltage), based on full load opera-
tion.
Battery Shutdown (15 Minutes) (Modules Only): When the battery voltage decreases to this limit
for five seconds during the first 15 minutes of the discharge, the battery circuit breaker opens to prevent
overdischarge. Note that the rated battery reserve time at your site may be other than 15 minutes.
Battery Shutdown (60 Minutes) (Modules Only): During extended outages or deep sags of more
than 15 minutes, the shutdown voltage limit will ramp up gradually to this 60-minute limit to prevent
lengthy discharge and possible battery damage. The battery circuit breaker opens when the battery
voltage and the shutdown limit are equal for five seconds. See the Battery Time screen for more infor-
mation. Also refer to the battery manufacturer’s manual, available on the manufacturer’s Web site.
Battery Rating (100%) (Modules Only). This setting is the full load discharge rating of the battery
in kilowatts for the rated backup period. A typical rating might be 500 kW for 15 minutes.
!
CAUTION
All alarm limit settings are application matched and factory-set. They should not be
changed casually. Contact Liebert Global Services for changing the alarm limit settings.
Overload Alarm................................................................ 104 %
DC Over Voltage.............................................................. 600 VDC
Battery Discharging ......................................................... 480 VDC
Low Battery...................................................................... 437 VDC
Battery Shutdown (15 minutes) ....................................... 384 VDC
Upper Point (60 minutes)................................................. 427 VDC
Battery Rating (100%) ..................................................... 500 KW 15 min
Battery Rating ................................................................. 250 KW 45 min
Battery Float Voltage ....................................................... 540 VDC
Temperature Limit Settings.............................................. 34°C
EXIT
UP: CURSOR UP
DOWN: CURSOR DOWN
SELECT: CHOOSE
ALARM SETTINGS
SECURITY ACCESS