Re: Fan direction on TEK485

Richard Knoppow

One reason for positive pressure cooling is that it reduces dust. Air is draw in through the filter which removes the dust (one hopes) and blows it through out the chassis.
However, positive pressure works when the chassis is designed for it, otherwise cooling may be better with a fan blowing out to exhaust warm air. Positive pressure design is not trivial; you want the greatest cooling where the greatest amount of heat is produced but don't want that air heating up the rest of the chassis. The chassis must be sealed well enough to control the air flow. Sometimes the blower must be some distance away from the hot spots.

On 8/20/2019 2:54 PM, Jokken Feldhaar wrote:
The 485 has the wonderful temp controlled Siemens motor and impeller design
fan. It draws the air in through the enclosure and expels it at the back of
the scope.
Quite the opposite: The fan will draw in air at the back of the 485, and you can feel the warm air coming out of the case to the left and right front sides of the front panel. BTDT, just last week I wanted to stop my workplace 485 humming loudly. As an extra, you might ask yourselves why the aluminum mesh filter and the foam filter is on the back side of the instrument - because the air enters exactly there.
Regards, Jochen DH6FAZ
Richard Knoppow

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