Types Of Cabinet - Siemens CPU 313C Hardware And Installation Manual

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The table below gives you an overview of the commonly used cabinet types. It
shows you the applied principle of heat dissipation, the calculated maximum power
loss and the degree of protection.
Table 5-5

Types of cabinet

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Enclosed Increased
ventilation via enclosed
natural convection ventilation
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)
S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
A5E00105492-03
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Natural convection Forced convection
with rack fan,
improvement of
natural convection
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
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Forced convection
with heat
exchanger, internal
and external
auxiliary ventilation
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
5-13