Siemens SIMATIC S7-400 Hardware And Installation Manual page 44

Installing the S7-400
Table 2-1 provides an overview of the most common types of cabinet. You will also
find the principle of heat removal, as well as the estimated, maximum achievable
power loss removal and the degree of protection.
Table 2-1 Types of Cabinet
Open Cabinets
Through-ventilation Increased
by natural through-ventilation
convection
Heat removal Increased heat
primarily by natural removal through
thermal increased air
convection, small movement
portion via the
cabinet wall
Degree of Degree of
protection IP 20 protection IP 20
Typical removable power dissipation under the following boundary conditions:
Cabinet size 2200 x 600 x 600 mm
Difference between external and internal temperature of the cabinet: 20 C (for other temperature
differences, you must refer to the temperature characteristics of the cabinet manufacturer)
up to 700 W up to 2700 W
(1400 W with very
fine filter)
2-24
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Closed Cabinets
Natural convection Forced circulation
using fan
subassembly,
enhanced natural
convection
Heat removal only Heat removal only
through the cabinet through the cabinet
wall; only low wall. Forced
power dissipation ventilation of the
permissible. Heat internal air results
accumulation in improved heat
usually occurs in removal and
the top of the prevention of heat
cabinet. accumulation.
Degree of Degree of
protection IP 54 protection IP 54
up to 260 W up to 360 W
S7-400 and M7-400 Programmable Controllers, Installation Manual
Forced circulation
using heat
exchanger,
external ventilation
inside and outside
Heat removal
through exchange
between heated
internal air and
cold external air.
The increased
surface of the
folded-area
sectional wall of
the heat
exchanger and
forced circulation
of internal and
external air permit
good heat output.
Degree of
protection IP 54
up to 1700 W
C79000-G7076-C424-01