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3.2 Ambient conditions
3.2.1 Heat Generation and Cooling
December 2001
The permissible ambient temperature in operation is between 0 °C and 45 °C.
Any deviation from this will impair the operating safety of the machine.
The permissible storage temperature is between –35 °C and +65 °C.
The following measures can ensure adequate heat removal:
n
Provide sufficient space for air circulation.
n
Build in a fan to intensify the natural convection. The fan must extract the
warm air from the logic unit. There must be no pre-warmed air blown into
the unit. The warmed air should flow over surfaces that have good thermal
conductivity to the external surroundings.
n
For a closed steel housing without assisted cooling, the figure for heat
conduction is 3 watt/m
between inside and outside.
n
Use of a heat exchanger with separate internal and external circulation.
HEIDENHAIN advises against blowing external air through the control cabinet
to replace the internal air. Electronic assemblies may be adversely affected by
fine dust or vapors. If no other method of cooling is possible, then ensure that
the fan extracts the warmed air from the electrical cabinet and that the air
drawn in is adequately filtered. Regular servicing of the filter is essential.
Ambient conditions
2
of surface per °C air temperature difference
3 – 7
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