Siemens Simatic S7-300, Hardware And Installation Manual, Page: 41 / 242

Configuring
S7-300 Programmable Controller Hardware and Installation
A5E00105492-01
4-13
Permissible ambient temperatures ...
are found in the Appendix Ambient Conditions.
4.7 Sample application: Selecting a cabinet
Introduction
The sample below clearly shows the maximum permissible ambient air
temperature at a specific power loss for different cabinet designs.
Installation
The following device configuration should be installed in a cabinet:
•
1 central device 150 W
•
2 expansion devices, each with 150 W
•
1 load power supply unit, 200 W under full load
This results in a total power loss of 650 W.
Power loss dissipated
The diagram in the figure below shows guide values for the permissible ambient air
temperature of a cabinet with the dimensions 600 mm x 600 mm x 2,000 mm,
depending on power loss. these values only apply if you maintain the specified
installation and clearance dimensions for module racks (profile rails).
200
400 600 800 1000 1200 1400 W
Loss of heat
20
30
40
50
60
Ambient temperature
in C
o
1
2
3
closed cabinet with
natural and forced
ventilation
with device fan
Cabinet with enclosed
ventilation by self-convention.
Closed cabinet with heat exchanger; size of heat
exchanger 11/6 (920 x 460 x 111 mm)
Figure 4-6 Power loss dissipated