Motorola MVME2600 manual Cooling Requirements

A

Specifications

Cooling Requirements

The Motorola MVME2603/2604 family of single board computers is specified, designed, and tested to operate reliably with an incoming air temperature range from 0° to 55° C (32° to 131° F) with forced air cooling of the entire assembly (base board and modules) at a velocity typically achievable by using a 100 CFM axial fan. Temperature qualification is performed in a standard Motorola VME system chassis. 25-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 the ambient air temperature and the type, number, and location of boards and 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 more favorable thermal conditions, it may be possible to operate the module reliably at higher than 55° C with increased airflow. 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 and speed of air flowing over a module.

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