Basic Emc Rules - Siemens SINAMICS G120D Series Operating Instructions Manual

4.2.2

Basic EMC Rules

Measures to limit Electromagnetic Interference (EMI)
Listed below are the necessary measures that must be taken to ensure the correct
installation of the Inverter within a system, which will minimize the effect of EMI.
Cables
● Keep all cable lengths to the minimum possible length; avoid excessive cable lengths.
● Route always signal and data cables, as well as their associated equipotential bonding
cables, in parallel and with as short a distance as possible.
● Don't route signal and data cables and line supply cables in parallel to motor cables.
● Signal and data cables and line supply cables should not cross motor cables; if crossing
is necessary, they should cross at an angle of 90 °.
● Shield signal and data cables.
● Route particularly sensitive signal cables, such as setpoint and actual value cables, with
optimum shield bonding at both ends and without any interruptions of the shield.
● Ground spare wires for signal and data cables at both ends.
● Route all power cables (line supply cables, as well as motor cables) separately from
signal and data cables. The minimum distance should be approximately 25 cm.
Exception: hybrid motor cables with integrated shielded temperature sensor and brake
control wires are allowed.
● Shield the power cable between inverter and motor. We recommend shielded cables with
symmetrical three-phase conductors (L1, L2, and L3) and an integrated, 3-wire, and
symmetrically arranged PE conductor.
Cable shields
● Use shielded cables with finely stranded braided shields. Foil shields are not suitable
since they are much less effective.
● Connect shields to the grounded housings at both ends with excellent electrical
conductivity and a large contact area.
● Bond the cable shields to the plug connectors of the inverter.
● Don't interrupt cable shields by intermediate terminals.
● In the case of both, the power cables and the signal and data cables, the cable shields
should be connected by means of suitable EMC shield clips or via electrically conductive
PG glands. These must connect the shields to the shield bonding options for cables and
the unit housing respectively with excellent electrical conductivity and a large contact
area.
● Use only metallic or metallized connector housings for shielded data cables (e. g.
PROFIBUS cables).
Converter with control units CU240D-2
Operating Instructions, 04/2015, FW V4.7.3, A5E34262100B AB
Installation
4.2 Electrical Installation
33