Siemens SINAMICS S120 Equipment Manual page 52

Electrical installation
4.3 Introduction to EMC
The most important measures for reducing bearing currents:
● Insulated motor bearing at the non-drive end
● Use of cables with a symmetrical cable design:
● Use of motor reactors (option L08) or dv/dt filters (option L10)
● Preferential use of a supply with isolated neutral (IT system)
● Use of grounding cables with low impedance in a broad frequency range (DC up to
● Separate HF equipotential-bonding cable between motor housing and driven machine
● Separate HF equipotential-bonding cable between motor housing and converter PE
● 360° HF contacting of the cable shield on the motor housing and the converter PE
● Use of common-mode filters
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The insulated bearing is standard for all 1LA8 motors designated for converter operation.
An insulated bearing at the non-drive end is available as an option for motors of the
1LG4/1LG6 series starting at frame size 280.
Concentric
copper or aluminum
shield
Figure 4-3 Use of cables with a symmetrical cable design
approximately 70 MHz), for example, plaited copper ribbon cables, HF litz wires
busbar
busbar. This can be achieved using EMC screwed glands on the motor end and EMC
shield clips on the converter end, for example.
Steel armor
S120 Cabinet Modules Equipment Manual
Manual, (GH5), 10/2008, A5E00427098A