Reducing Bearing Currents When Operated With A Converter - Siemens SIMOTICS XP Operating Instructions Manual

NOTICE
Material damage caused by an excessively high supply voltage
The insulation system will be damaged if the supply voltage is too high for the insulation
system. This can completely destroy the machine.
• Comply with the peak voltages as laid down in the guidelines above.
4.14.3

Reducing bearing currents when operated with a converter

Taking the following actions will reduce the bearing currents:
• Ensure that the contacts are made over a large area. Solid copper cables are not suitable
for high-frequency grounding because of the skin effect.
• Install the equipotential bonding conductor in parallel with the motor cable, as close as
possible and avoid creating any loops.
Equipotential bonding conductors:
Use equipotential bonding conductors:
• between motor and driven machine
• between motor and converter
• between the terminal box and the RF grounding point at the motor enclosure.
Selecting and connecting the cable:
As far as possible, use symmetrically arranged, shielded connection cables. The cable
shielding, made up of as many strands as possible, must have good electrical conductivity.
Braided shields made of copper or aluminum are very suitable.
• The shield is connected at both ends, at the motor and converter.
• To ensure good discharging of high-frequency currents, provide contacting over a large
surface area:
– as contact established through 360° at the converter
– at the motor, for instance with EMC glands at the cable entries.
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Operating Instructions, 10/2021, A5E41926185A
Preparations for use
4.14 Converter operation
47