Additional Installation Tips
7.4 Ambient Temperature
The maximum ambient temperature for the operator panel is provided in the
specifications. The ambient temperature refers to the temperature in the device
cabinet which cools the operator panel’s electronics.
Operator
panel
Power
Power
Power
30 °C outside
Top
50 °C inside
Bottom
40 °C inside
Middle
45 °C inside
Airflow
Axial fan
120 x 120 mm
In most cases, the ambient temperature for the operator panel is significantly
higher than the device cabinet’s ambient temperature.
If the cabinet is tall and there are a number of heat-generating devices, the
temperature at the top of the cabinet will be considerably higher than the
theoretical temperature increase that would be expected. All electronics are
sensitive to heat. The lifespan of an electrolytic capacitor is cut in half with an
8-10 °C increase in temperature. A 15-20 °C temperature increase results in a
quarter of the lifespan etc.
Rittal has a good program for estimating the anticipated average temperature in
the cabinet as well as a large program for controlling the temperature in the device
cabinet.
An enamel-coated steel cabinet has a radiant heat value of 5.5 W/m
2
and degrees
C.
Installing a fan inside the cabinet will even out the temperature, while moving air
provides considerably better cooling than still air.
Install the fan so that it sits in the cooler area and blows cold air against the operator
panel. If the fan is mounted at the top and sucks warm air upwards, the fan’s
ambient temperature will be higher, resulting in a shorter lifespan.
The operator panel’s loss effect = supply voltage x current. Virtually no power goes
to external users and no loss effects due to inputs.
Beijer Electronics, MAEN083E
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