Cabinet design and EMC
5.3 Notes on control cabinet climate control
Air-Cooled Chassis Power Units - supplement to Motor Module 6SL3320-1TG41-5AA3
Equipment Manual, 10/2020, A5E50422764A
63
Due to the flow of air within the cabinet, the device fan draws in pre-heated air. This heats up
the components considerably and the fan does not function effectively.
NOTICE
Device failure due to air short-circuit in the control cabinet
Short-circuits in the cooling air circuit as a result of unsuitable air guidance can result in
overheating in the electrical cabinet and in turn failure of devices.
•
Install suitable barriers in the control cabinet in order to prevent an air short-circuit from
occurring.
Barriers must be installed in such a way that no air can flow along the outer sides on the top
and bottom of the devices. In particular, air must be prevented from flowing from the top
(warm discharged air) to the bottom (cold cooling air). Suitable plates can be used as
barriers. The barriers must reach up to the side panels or cabinet doors. They must be set up
in such a way that the outgoing air current is not forced into the cabinet cross-beams, but is
instead diverted around them. Barriers must be in place for all degrees of protection higher
than IP20.
The cabinets adjacent to the converter cabinets must also be taken into account when
barriers are installed.
To ensure adequate ventilation of the equipment, the minimum opening sizes specified in
the following table must be observed.
The specified opening cross-sections comprise several small openings. To ensure that
pressure loss is kept to a minimum and that the flow resistance does not become too great at
these mesh-type openings, the cross sectional area of each opening must be around at least
190 mm² (e.g. 7.5 mm x 25 mm or 9.5 mm x 20 mm). The total opening cross-section to be
provided is specified for each device in the table below.
To ensure that the devices operate continuously, suitable measures must be taken to prevent
the ingress of dirt and dust. Wire lattices (wire fabric DIN 4189-St-vzk-1x0.28) or filter mats
(min. filter class G2) must be used for this purpose. The choice of filter mats depends on the
required degree of protection and the ambient conditions. If cabinets are installed in an
environment containing fine dust particles or oil vapors, micro-filter mats must be used to
prevent the devices from becoming contaminated.
If dirt filters are used, the specified opening cross-sections and the filter areas must be
adjusted upwards.
NOTICE
Device failure due to overheating as a result of contaminated dirt filters
Contaminated filter mats cause the device to overheat and fail.
•
If dirt filters are used, observe the specified replacement intervals.
If the filter mats are heavily contaminated, the volume of air drawn is reduced due to the
increased flow resistance. This can cause the fans integrated in the devices to overload, or it
could cause the devices themselves to overheat and become damaged.
