Siemens SIMATIC S7-300 Hardware And Installation Manual page 40

Configuring
Open cabinets
Mainly inherent Higher heat
heat dissipation, dissipation with
with a small portion increased air
across the cabinet movement.
wall.
Degree of Degree of
protection IP 20 protection IP 20
Typical power dissipation under following marginal conditions:
•
Cabinet size: 600 mm x 600 mm x 2,200 mm
•
Difference between the outer and inner temperature of the cabinet is 20 °C (for other temperature
differences refer to the temperature charts of the cabinet manufacturer)
up to 700 W up to 2,700 W (with
fine filter up to
1,400 W)
The cabinet's power dissipation
The power dissipation capability of a cabinet depends on its type, ambient
temperature and on the internal arrangement of devices.
Details on power dissipation ...
is found in the Siemens catalogs NV21 and ET1.
Cabinet dimensions
Note the following specifications when you determine the dimensions of a cabinet
suitable for an S7-300 installation:
• Space required for module racks (profile rails)
• Minimum clearance between the module racks and cabinet walls
• Minimum clearance between the module racks
• Space required for cable ducts or fans
• Position of the stays
Warning
Modules are liable to get damaged if exposed to inadmissible ambient
temperatures.
4-12
Closed cabinets
Heat dissipation Heat dissipation
only across the only across the
cabinet wall; only cabinet wall.
low power losses Forced convection
permitted. In most of the interior air
cases heat improves heat
concentration dissipation and
develops at the top prevention of heat
of the cabinet concentration.
interior.
Degree of Degree of
protection IP 54 protection IP 54
up to 260 W up to 360 W
S7-300 Programmable Controller Hardware and Installation
Heat dissipation by
heat exchange
between heated
internal air and
cool external air.
The increased
surface of the
pleated profile of
the heat exchanger
wall and forced
convection of
internal and
external air provide
good heat
dissipation.
Degree of
protection IP 54
up to 1,700 W
A5E00105492-01