Siemens SINAMICS G120 Operating Instructions Manual page 24

Installing
4.2 EMC-compliant cabinet design
The different zones must be electromagnetically decoupled. One method is to ensure that
the zones are not positioned directly next to each other (minimum distance app. 25 cm / 9.84
in). A better, more compact method, however, is to use separate metallic housings or
separation plates with large surface areas.
Cables within each zone can be unshielded. Cables connecting different zones must be
separated and must not be routed within the same cable harness or cable channel. If
necessary, filters and/or coupling modules should be used at the interfaces of the zones.
Coupling modules with electrical isolation are an effective means of preventing interference
from spreading from one zone to another.
All communication and signal cables leaving the cabinet must be shielded. For longer,
analog signal cables isolating amplifiers should be used. Sufficient space for bonding the
cable shields must be provided, whereby the braided cable shield must be connected to the
cabinet ground with excellent electrical conductivity and with a large contact area.
Differences in the ground potential between the zones must be avoided to ensure that
impermissible, high compensating currents are kept away from the cable shields.
Division of the cabinet and installation into different EMC zones
22
 Zone A:
Supply connection
Limit values for conducted
interference emissions and
conducted interference immunity
must not be exceeded
 Zone B:
Power electronics
Sources of interference
 Zone C:
Controller and sensors
Potentially susceptible
equipment
Zone D:
Motor, braking resistor and
according cables
Sources of interference
SINAMICS G120C frequency converter
Operating Instructions, 03/2012, FW V4.5, A5E02999804B AB