Avoid Electromagnetic Interference (Emi) - Siemens SINAMICS G120 Original Instructions Manual

Installing
4.5 Connecting inverters in compliance with EMC
4.5.2

Avoid electromagnetic interference (EMI)

The inverters are designed to operate in an industrial environment where a high level of EMI
can be expected. Safe, reliable and disturbance-free operation is only guaranteed if the
devices are professionally installed.
Control cabinet design
● Connect the metal parts and components of the control cabinet to the control cabinet
frame through a good electrical connection:
– Side panels
– Rear panels
● Connect the PE bar and the EMC shield bar to the control cabinet frame through a good
● Connect the metal enclosures of the devices in the cabinet, e.g. converter or line filter, to
● Choose one of the following methods to establish a conducting contact for screw
connections on painted or anodized surfaces:
– Use special contact (serrated) washers that cut through the
– Remove the insulating surface at the contact locations
● Equip the following devices with interference suppression elements:
– Coils of contactors
– Relays
– Solenoid valves
– Motor holding brakes
Interference suppression elements are RC elements or varistors with AC coils and free-
wheeling diodes or varistors for DC coils.
Connect the interference suppression elements directly at the coil.
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– Roof
– Base plates
Using the highest possible surface area or a high number of individual screw
connections.
electrical connection established through a large surface area.
the control cabinet frame through a good electrical connection through the largest
possible surface area.
We recommend to mount these devices on a bare metal mounting plate with good
conducting characteristics.
Inverter with CU230P-2 Control Units
Operating Instructions, 11/2013, FW V4.6.6, A5E02430659B AG