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Specifications
General specifications for the MVME177 are listed in Table 1-3.
The following sections detail cooling requirements and FCC
compliance.
Cooling Requirements
The Motorola MVME177 VMEmodule is specified, designed, and
tested to operate reliably with an incoming air temperature range
from 0û to 55û C (32û to 131û F) with forced air cooling at a velocity
typically achievable by using a 100 CFM axial fan. Temperature
qualification is performed in a standard Motorola VMEsystem
chassis. Twenty-five watt load boards are inserted in 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 100 CFM per fan, is placed directly under the VME
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 vendors specifications are not
exceeded.
While the exact amount of airflow required for cooling depends on:
adequate cooling can usually be achieved with 10 CFM and 490
LFM flowing over the module. Less airflow is required to cool the
module in environments having lower maximum ambients. Under
Ambient air temperature
Type of board
Number of boards
Location of boards
Other heat sources
Specifications
1
1-3
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