30 Guidelines for planning the cabinet installation
galvanic metal contact in the covering cabinet structure is 100 mm (3.94 in). 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, we
recommend to leave the seams between the panels 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 (3.94 in).
• 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.
• 360° high frequency grounding of the cable shields at the cable entries improves
the EMC shielding of the cabinet.
• ABB recommends 360° high frequency grounding of the motor cable shields at
their entries. The grounding can be implemented by a knitted wire mesh
screening as shown below. In US installations, you can use cable conduit entry.
1Cable
2 Cable tie
3 Strain relief
4 Bare cable shield
5 Knitted wire mesh
6 Bottom plate
To Next Page
Loading...
