|This unusual, L-shaped, chassis is a component in a satellite data ground station. The complete system has three or four of these chassis mounted one above the other in a 19" wide rack. The chassis contains a double-sided VME backplane, a removable fan tray, and a triple-redundant power system in the rear extention.|
The openings in the top, bottom and sides are for the stacked cooling.
Air is drawn into the chassis from the front, through
a filter mounted in the front cover. The air is blown up, through the card cage, and also to the rear, through the
power supplies. From the card cage, air is exhausted from the chassis through the openings on the top surface and
along the top edge of the sides. Since the chassis are stacked one above the other in a rack, the air leaving the
top surface vents of one chassis enters corrosponding bottom surface vents of the one above it, hits the underside
of the V-shaped fan tray, and leaves the chassis through the openings along the bottom edge of the side panels.
With the decorative front panel removed, the front side of the card cage can be accessed. The backplane has
18 slots on this side. It was custom designed for this chassis. Also on the front panel is a set of LED power
status indicators. The inlet to the fan tray is below the card cage. If necessary for maintenance, the fan tray
can be slid out from this side.
From the rear of the chassis, the back side of the card cage and backplane are accessible. This side
also has 17 VME slots. There are a total of 36 slots, front and back, in this backplane.
The backplane is divided into five separate, independent VME busses.
The triple-redundant power system consists of three, independent power supply modules, and a power distribution board, that combines the outputs of the three supplies and distributes power to the backplane. The distribution board also contains monitoring circuits that drive the LEDs on the front panel.
When required, the power supply modules can be simply unplugged from the chassis.
The removable power supply modules contain an open-frame DC power supply, AC input connector/line filter,
AC power switch, primary fuse holder, and components that allow the outputs of the power supply to be
paralleled. All of these components are enclosed in a sheet metal shell for safety and convience. The design
of the paralleling circuitly allows a power module to be hot-swapped without disturbing the operation of the
The chassis is made of 16 gauge steel. The decorative front cover is painted gray enamel with a medium texture. The inner front panel is medium textured black enamel. The rest of the chassis is plated with clear zinc. The dimensions of the chassis are 19"W x 17.5"H (10U) x 29"D.
Based on the customer requirements, Zoltech designed and fabricated the chassis. We created the mechanical specifications for the custom backplane. We also procured all of the internal components (except for the VME modules), assembled and tested the complete chassis, including the removable power supplies.