ABB ACS850-04 series, Hardware Manual

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Planning the cabinet installation
41
Planning the cabinet placement on a cable channel
Note the following when planning to place the cabinet on a cable channel:
• The cabinet structure must be sturdy enough. If the whole cabinet base will not be
supported from below, the cabinet weight will lie on the sections that the floor
carries.
• Equip the cabinet with a sealed bottom plate and cable lead-throughs to ensure
the degree of protection and to prevent the cooling air flow from the cable channel
into the cabinet.
Planning the electromagnetic compatibility (EMC) of the cabinet
Note following when planning the electromagnetic compatibility of the cabinet:
• Generally, the fewer and smaller the holes in the cabinet, the better the
interference attenuation. The maximum recommended diameter of a hole in
galvanic metal contact in the covering cabinet structure is 100 mm. Pay special
attention to the cooling air inlet and outlet gratings.
• The best galvanic connection between the steel panels is achieved by welding
them together as no holes are necessary. If welding is not possible, the seams
between the panels
are recommended to be left unpainted and equipped with
special conductive EMC strips to provide adequate galvanic connection. Usually,
reliable strips are made of flexible silicon mass covered with a metal mesh. The
non-tightened touch-contact of the metal surfaces is not sufficient, so a
conductive gasket between the surfaces is required. The maximum
recommended distance between assembly screws is 100 mm.
• Construct sufficient high-frequency grounding network in the cabinet to avoid
voltage differences and forming of high-impedance radiator structures. A good
high-frequency grounding is made with short flat copper braids for low
inductance. One-point high-frequency grounding cannot be used due to the long
distances inside the cabinet.
The carrying structure on a cable channel Cabinet side view with a bottom plate