Siemens S5-135U/155U - Manual (Page 63)

3-37
System Manual
C79000-G8576-C199-06
3.7.3 Removal of Power Dissipation from Cabinets
The power dissipation that can be removed from a cabinet is governed by the
cabinet design, its ambient temperature and the arrangement of equipment in
the cabinet.
Shown in the following figure is a diagram with guide values for the
permissible ambient temperature of a cabinet measuring 600 x 600 x 2200
mm, as a function of power dissipation. These values only apply to the
arrangement of equipment in the cabinet as given in Section 3.6.2. Further
details can be found in Catalogs NV21 and ET1.
20
30
40
50
55
200 400 600 800 1000 1200 1400 W
Power Dissipation
Ambient Temperature
in
o
C
1
2
3
1 Closed cabinet with heat exchanger of size 11/6 (920 x 460 x 111 mm)
2 Cabinet with through-ventilation by natural convection
3 Closed cabinet with natural convection and forced circulation using fan
Figure 3-16 Maximum Cabinet Ambient Temperature as a Function of Power Dissipation
Note
When fitting the subracks of the S5-135U/155U series, the maximum power
dissipation which can be removed by the fans must not be exceeded. The
maximum removable power dissipation per unit with a supply air
temperature of 55
°
C is 250 W. This value is increased by 20 W for each
reduction in supply air temperature by 1
°
C.
Installation Guidelines