Insulated Bearings For Converter Operation - Siemens SIMOTICS XP Operating Instructions Manual

Preparations for use
4.14 Converter operation
• If the cable shield is connected as described, then it ensures the specified equipotential
bonding between the motor enclosure and converter. A separate RF equipotential
bonding conductor is then not necessary.
• If the cable shield is not connected due to special secondary conditions, or not adequately
connected, then the specified equipotential bonding is not provided. In this particular
case, use a separate RF equipotential bonding conductor:
– Between the motor enclosure and protective ground rail of the converter.
– Between motor enclosure and driven machine
– Use braided flat copper straps or high-frequency cables with finely-stranded
– Ensure that the contacts are made over a large area.
Measures to reduce bearing currents
To specifically reduce bearing currents, you must consider the system as a whole, which
comprises the motor, converter, and driven machine. The following measures support you
when reducing bearing currents and help to avoid damage:
• In the overall system, set up a properly meshed grounding system with low impedance.
• Use the common-mode filter (damping cores) at the converter output. The Siemens sales
representative is responsible for selection and dimensioning.
• Limit the rise in voltage by using output filters. Output filters dampen the harmonic
content in the output voltage.
• The operating instructions for the converter are not part of this documentation. Refer to
the configuration information for the converter.
4.14.4

Insulated bearings for converter operation

If the machine is controlled from a low-voltage converter, depending on the machine type,
an insulated bearing can be fitted at the NDE.
An insulated speed encoder can be optionally mounted.
Comply with the information provided on the machine plates relating to bearing insulation
and possible jumpers.
48
Concentric copper or aluminum shield
conductors for the separate RF equipotential bonding cable.
Steel armor
1MB..5/6 shaft height 71 ... 355
Operating Instructions, 10/2021, A5E41926185A