Siemens SIMATIC S7-400 Hardware And Installation Manual page 46

Installing the S7-400
Example for Determining the Type of Cabinet
The following example clarifies the maximum ambient temperature which is
permissible for a particular power dissipation with various types of cabinet.
The following equipment configuration is to be installed in a cabinet:
1 central rack
2 expansion racks of 150 W power dissipation each
1 load current power supply under full load
Total power dissipation
From Figure 2-2, with a total power dissipation of 650 W, the ambient temperatures
obtained are as follows:
Closed, with natural convection and forced circulation
(Curve 3)
Open, with through-ventilation (Curve 2)
Closed, with heat exchanger (Curve 1)
Dimensions of Cabinet
To determine the dimensions of a cabinet suitable for assembling an S7-400, you
must take the following into account:
Space requirement of the racks
Minimum clearances between racks and cabinet walls
Minimum clearances between racks
Space requirement of cable ducts or fan subassemblies
Locations of rails
2-26
www.gkbpx.com
Type of Cabinet
S7-400 and M7-400 Programmable Controllers, Installation Manual
150 W
300 W
200 W
650 W
Max. Permissible Ambient
Temperature
(no operation possible)
approx. 38 C
approx. 45 C
C79000-G7076-C424-01