Siemens S5-135U/155U - Manual (Page 64)

3-38
System Manual
C79000-G8576-C199-06
!
Caution
Modules with a hard disk drive can only be used at an ambient temperature
of up to 50
°
C.
3.7.4 Examples for Determining the Type of Cabinet
The following example shows the maximum permissible ambient
temperature with various cabinet types and the same power dissipation.
Example
The following equipment configuration is given:
1 Central controller 200 W
2 Expansion units, 250 W power dissipation each 500 W
1 Load PS, 24 V/40 A, 6EV1 362-5BK00 (full load) 200 W
Total power disspation 900 W
From Figure 3-16, with a total power dissipation of 900 W, the maximum
ambient temperatures given by the table are as follows:
Cabinet Design Max. Permissible Ambient
Temperature
Closed, with natural convection and forced
circulation (Curve 3) (Operation not possible)
Open with through-ventilation (Curve 2) Approx. 33
°
C
Closed, with heat exchanger (Curve 1) Approx. 42
°
C
Installation Guidelines