Product Introduction
Liebert
®
APS
™
10
1.4
Operating Modes
The Liebert APS UPS is a true online double-conversion system, having the following operating
modes:
• Normal Mode
• Backup Mode
• Auto Restart Mode
• Bypass Mode
Normal Mode
The power module rectifiers derive power from a utility AC source and supply regulated DC power to
the inverter. The module’s inverter regenerates precise AC power to supply the connected equipment.
The battery charger is in the power module and maintains a float-charge on the batteries of the UPS;
additionally, the optional charger module can also charge the batteries to maintain a quicker
recharge time for long backup time applications.
Backup Mode
When AC utility fails, the connected equipment is supplied power by the inverter, which obtains
energy from the battery modules. The output power will not be interrupted during the failure or
restoration of the AC utility/mains source.
Auto Restart Mode
After a power outage and complete battery discharge, and once AC utility is restored, the UPS will
automatically restart and resume supplying power to connected equipment. This feature is enabled at
the factory, but can be disabled by the user. The user can also program two auto restart delay settings
from the LCD:
• Battery capacity level (%)
• Countdown timer
Bypass Mode
The bypass provides an alternate path for power to the connected equipment and operates in the
following manner:
• Automatic: In the event of an internal fault or should the inverter overload capacity be exceeded,
the UPS performs an automatic transfer of the connected equipment from the inverter to the
bypass source.
• Manual: Should the UPS need to be taken out of service for limited maintenance or repair,
manual activation of the bypass will cause an immediate transfer of the equipment from the
inverter to the bypass source.
Summary of Contents for Liebert APS
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