Siemens SINAMICS G120 Operating Instructions Manual page 25

Control cabinet design
● All metallic components of the cabinet (side panels, back walls, roof plates, and floor
● The cabinet doors must be connected to the cabinet frame with excellent electrical
● The PE busbar and EMC shield busbar must be connected to the cabinet frame with
● All metallic housings of devices and additional components integrated in the cabinet
● All connections should be made so that they are permanent. Screwed connections on
● Contactor coils, relays, solenoid valves, and motor holding brakes must have interference
SINAMICS G120C frequency converter
Operating Instructions, 03/2012, FW V4.5, A5E02999804B AB
plates) must be connected to the cabinet frame with excellent electrical conductivity,
ideally with a large contact area or by means of several point-like screwed connections
(i.e. to create a Faraday cage).
conductivity by means of short, finely stranded, braided grounding strips, which are
ideally placed at the top, in the middle, and at the bottom of the doors.
excellent electrical conductivity with a large contact area.
(such as converter or line filter) must be connected to the cabinet frame with excellent
electrical conductivity and with a large contact area. The best option here is to mount
devices and additional components on a bare metal mounting plate (back plane) with
excellent electrical conductivity. This mounting plate must be connected to the cabinet
frame and, in particular, to the PE and EMC shield busbars with excellent electrical
conductivity and a large contact area.
painted or anodized metal components must be made either by means of special contact
washers, which penetrate the isolating surface and establish a metallically conductive
contact, or by removing the isolating surface on the contact points.
suppressors to reduce high-frequency radiation when the contacts are opened (RC
elements or varistors for AC currentoperated coils, and freewheeling diodes for DC
current-operated coils). The interference suppressors must be connected directly on each
coil.
4.2 EMC-compliant cabinet design
Installing
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