Vertiv Liebert STS2 - System Components

Vertiv™ | Liebert® STS2/PDU
™
User Manual | Rev. 6 | 10/2017 117
14.2 System Components
All Liebert STS2/PDU models provide two isolation transformers connected to a solid-state, three-pole,
dual-position static transfer switch within one enclosure, with the ability to transfer between two input sources to
a single output.
All Liebert STS2/PDU’s are configured with an LCD Color Graphical Interface touchscreen for monitoring and
configuring the unit.
14.2.1 Frame and Enclosure
The complete Liebert STS2/PDU is housed in a freestanding enclosure. The cabinet is a NEMA type 1 enclosure.
The cabinet is structurally designed to handle lifting from the base. The frame is designed to accommodate floor
stands.
The distributed floor weight for Liebert STS2/PDU is less than 260 lb./sq. ft. (118 kg/m
2
).
The required service access is front and one side of the unit, 250A without output cabinet is front access only.
Side access depends on which side the output cabinet is mounted, can be left or right.
The Liebert STS2/PDU can be tipped 15° in any direction without falling over.
14.2.2 Casters - 250A only
The 250A unit frame includes heavy-duty swivel casters for ease of installation, plus stabilizing feet for final
installation.
14.2.3 Cooling
The Liebert STS2/PDU 250A units utilize convection air cooling for the enclosure with forced air cooling of the
heat sinks.
The 400-800A units are fan cooled using low-velocity fans to minimize audible noise. All fans are redundant so
that a single fan failure cannot cause temperatures to increase beyond acceptable limits.
Air intake is through screened protective openings in the front of the unit. A standard furnace filter
is installed behind the openings.
By opening the front door, the filter can be changed easily without exposing personnel to high voltage. The size
of the filter is 1 in. x 25 in. x 25 in. (2.54 cm x 63.5 cm x 63.5 cm).
The air exhaust is through the top of the unit.
Table 26 Frame sizes
Rating
Width x Depth x Height
in. (mm)
250A 60 x 32 x 77 (152 x 81 x 196)*
400 – 600A 73 x 49 x 77 (186 x 125 x 196)
800A 96 x 49 x 77 (244 x 125 x 196)
* Width is 76.8 in (195 cm) with output distribution cabinet