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VV-11 FAMILYVERSATILE VMESYSTEM CHASSIS
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Effective cooling is a critical function of any system chassis: Good airflow will add
siginficantly to component life and system reliability. It will also protect fragile
mass storage devices and media from dust and other contamination. Many other VME chassis
blow air AT the card cage rather than THROUGH it. Actual airflow past the cards is actually
quite low, requiring removal of chassis panels to allow heat to escape. Air filtering is
typically not provided. The VV-11 chassis solve these problems and provide the cooling that
reliable systems need.
In all VV-11 chassis, the airflow is channelled by the intake fans directly through the most critical components: the cards and the mass storage devices. The entire chassis is pressurized with filtered air. A small amount aof air is exhausted through any openings that may exist in front mounted disk or tape drives (rather than drawing unfiltered air into the drives, which is what chassis with exhaust fans will do). Efficient cooling is also provided for the DC power supply. The supply may be either "cross-mounted" (as shown in the diagram) or "side-mounted", depending on the chassis configuration.
Fans and air filters are mounted on the side of the VV-11 chassis and the airflow pattern is
from right side to left side. Intake and exhaust space is not required above or below the
chassis, as in some vertically-cooled designs. The filters are accessible from the outside of
the chassis. They may be removed for cleaning without tools, even if chassis slides are
installed. If the chassis is to be operated in a clean air environment, the fan filters may
be removed entirely to increase airflow while maintaining finger guard protection on the fans.
Some VV-11 chassis have as many as EIGHT fan mounting positions. One thousand watts or more can be safely dissipated in these chassis. Alternately, when the heat load is smaller, low velocity whisper fans can be used to minimize acoustic noise.