Converter Operation On A Grounded Network; Insulated Bearings When Operating The Converter - Siemens SIMOTICS TN Series Operating & Installation Instructions Manual

Overall system design
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
● Limit the rise in voltage by using output filters. Output filters dampen the harmonic content
Note
Converter documentation
The operating instructions for the converter are not part of this documentation. Refer also to
the configuration information for the converter.
4.15.4

Converter operation on a grounded network

NOTICE
Damage resulting from protective conductor currents
When the machine is operated on a converter with current limiter, but without ground-fault
monitoring, protective conductor currents of up to 1.7 times the external conductor current
can arise if there is a ground fault on the output side. Neither the PE conductors of normally
rated multi-core connecting cables nor the PE connecting points of normal terminal boxes
are suitable for this purpose. Material damage can result.
● Use an appropriately sized PE conductor.
● Connect the PE conductor to the grounding terminal on the motor enclosure.
4.15.5

Insulated bearings when operating the converter

If the machine is operated from a low-voltage converter, insulated bearings are fitted at the
NDE and an insulated encoder with insulated bearings (option).
Comply with the plates on the machine relating to bearing insulation and possible bridges.
SIMOTICS TN Series N-compact 1LL8
Operating Instructions 11/2018
representative is responsible for selection and dimensioning.
in the output voltage.
Preparations for use
4.15 Converter operation
41