Motorola MVME177 manual Specifications, Cooling Requirements

Specifications

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:

❏Ambient air temperature

❏Type of board

❏Number of boards

❏Location of boards

❏Other heat sources

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

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