Specifications
117
14.2.1 Frame and Enclosure
The complete STS2/PDU is housed in a freestanding enclosure. The cabinet is a NEMA type 1 enclo-
sure. The cabinet is structurally designed to handle lifting from the base. The frame is designed to
accommodate floor stands.
The distributed floor weight for STS2/PDU is less than 260 lbs./sq. ft. (118 kg/m²).
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 STS2/PDU can be tipped 15° in any direction without falling over.
14.2.2 Caster and Leveling - 250A only
The 250A unit frame includes heavy-duty swivel casters for ease of installation, plus permanent level-
ing feet for final installation.
14.2.3 Cooling
The 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 lim-
its.
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 25 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