Specifications

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Liebert Static Transfer Switch2
™
The Liebert Static Transfer Switch2 (STS 2) provides
an automatic, seamless transfer between the outputs
of two independent UPS systems and the input of a
critical load in a dual-bus power system. If the primary
UPS should fail, the switch will automatically transfer
the loads to the surviving UPS. For redundancy, the
Liebert STS2 features three separate, self-correcting
logic modules. Each controller is capable of working
independently and each helps monitor the other two.
Available in capacities ranging from 100 up to
1000 amps.
True Front-Access Design
All mechanical and electronic components of the
Liebert STS2 are accessible from the front of the unit.
This gives you several immediate benefits:
Greater freedom in system design. The Liebert
STS2 can be placed adjacent to or in back of other
equipment. It can also be placed against
a wall or partition.
Simplified installation, with ample space for cable
connections through top and bottom access plates.
Less floor space required for maintenance access.
Simplified maintenance, with all key components
visible, serviceable and removable from the front
of the unit, without the need to shut down the
connected load.
Other Features Of The Liebert
Static Transfer Switch2:
Internal CANBUS protocol provides high-bandwidth
communication between system components
via twisted-pair cables. Options can be added
as simple network nodes.
Internal dual-bus control power.
Simplified installation and maintenance.
Full range of communications options to fit
any monitoring strategy.
Three-pole switch configurations.
Optimized Transfer option uses the patented
Liebert static transfer control algorithm to eliminate
downstream transformer inrush saturation. Meets
CBEMA and ITIC standard for critical loads.
True Internal Redundancy
The Liebert STS2 has triple-redundant logic. Each DSP
controller is capable of working independently, and each
helps monitor the other two. If one malfunctions, the
other two lock it out. Each controller has power feeds
from both power supplies.
The two power supplies feature true dual-bus power
distribution. Both have dual inputs, one from each
AC input source. All power connections have diode
protection, so that internal or external faults cannot
propagate. The result is a rugged, fault-resilient package
that is optimized for real-world applications.
Easy-To-Use Color
Touch-Screen Interface
The controls of the Liebert STS2 are
intuitive and simple. The pop-up menus
are easy to understand and provide a
wealth of operational and diagnostic
information.
The color LCD monitor is divided into
three segments. In addition to a system
mimic diagram, there is a status/
alarm panel and a section dedicated
to operator instructions and menus.
You benefit from improved operator
effectiveness, reduced training time,
and less chance of operator error.
The Key To High-Availability Power.