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Cooling Requirements
Motorola VMEmodules are specified, designed, and tested to operate reliably
with an incoming air temperature range from 0 degrees C to 55 degrees C (32
degrees F to 131 degrees F) with forced air cooling.
Temperature qualification is performed in a standard Motorola MVME900
series chassis. Twenty-five watt load boards are inserted in the two card slots,
one on each side, adjacent to the board under test to simulate a high power
density system configuration. An assembly of three axial fans, rated at 71 CFM
per fan, is placed directly under the MVME card cage. The incoming air
temperature is measured between the fan assembly and the card cage where
the incoming airstream first encounters the module under test.
Test software is executed as the module is subjected to ambient temperature
variations. Case temperatures of critical, high power density integrated
circuits are monitored to ensure component vendor specifications are not
exceeded.
While the exact amount of airflow required for cooling depends on the
ambient air temperature and the type, number, and location of boards and
other heat sources, adequate cooling can usually be achieved with 5 CFM
flowing over the module. Less air flow is required to cool the module in
environments having lower maximum ambients.
Under more favorable thermal conditions it may be possible to operate the
module reliably at higher than 55 degrees C with increased air flow. It is
important to note that there are several factors, in addition to the rated CFM of
the air mover, which determine the actual volume of air flowing over a
module.
FCC Compliance
The MVME712-10 transition board was tested in an FCC-compliant chassis,
and meets the requirements for Class A equipment. FCC compliance was
achieved under the following conditions:
Shielded cables on all external I/O ports.
Cable shields connected to earth ground via metal shell connectors
bonded to a conductive module front panel.
Conductive chassis rails connected to earth ground. This provides the
path for connecting shields to earth ground.
Front panel screws properly tightened.
MVME712-10/D1
Specifications
1
1-3
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