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S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
A5E00105492-03
5-15
200
400 600 800 1000 1200
1400
Loss of heat in W
20
30
40
50
60
Ambient temperature in °C
1
1
2
3
Figure 5-6 Power loss dissipated
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Closed cabinet with heat exchanger (heat exchanger size 11/6 (920 mm x 460
mm x 111 mm)
Cabinet with through-ventilation by natural convection
Closed cabinet with natural convection and forced ventilation by equipment
fans
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From the diagram we can see that the following ambient temperatures are
obtained for a total power loss of 650 W:
Table 5-6 Choice of cabinets
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Closed with natural convection and forced ventilation
(Curve 3)
Operation not possible
Open with through-ventilation (Curve 2) approx. 38 °C
Closed with heat exchanger (Curve 1) approx. 45 °C
If you install the S7-300 horizontally, you can use the following types of cabinet:
• open, with closed ventilation
• closed, with heat exchanger
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Selection and installation of cabinets