How much clearance does a fanless machine need inside a cabinet, and should it be mounted flat or upright?

A fanless machine cools through its housing, so clearance and orientation decide the real operating temperature. Clearance: keep at least 50 mm free on the finned side and 25–30 mm on the others. Do not run cable ducts or place drives and power supplies against the fins — a variable-frequency drive is a large heat source, and mounting it directly below the computer sends its heat straight up into it. Orientation: the fins must be vertical so air travels up along the channels. Mounting the finned face downward, or with channels horizontal, blocks convection and can raise housing temperature by tens of degrees. Vendor datasheets show the permitted orientations; mount it differently and the published temperature range no longer applies. Inside the cabinet, place the machine in the middle or upper area but 100 mm below the roof, not at the bottom where dust collects. If the cabinet has filtered fans, arrange the airflow to sweep across the fins. After installation, measure the in-cabinet temperature at midday under real load and compare it with the machine rating.