Laying Signal Cables; Laying The Cable Shields; Separating Adjacent Cabinets Using Unsuppressed Contactors - Siemens SINAMICS MV 9LD4110-7EX70-1AA0 Operating Instructions Manual

Electrical connection

6.9 Separating adjacent cabinets using unsuppressed contactors

6.8

Laying signal cables

Malfunction due to common cable installation
Malfunctions can occur in the converter if cables with differing voltage levels are laid together
with internal cables in one cable duct in the cabinet.
• Do not run cables coming from the outside, for example to the terminal strips, together with
internal cables in one cable duct.
Ensure that the following instructions are complied with:
• All signal lines must be shielded. The cable shield should be braided, because cables shielded
by tape or foil are five times less efficiently protected against interference. Always ground the
cable shields at both ends. Contacting at one end is advantageous in exceptional cases only.
• Clamp the shield of incoming analog and binary cables to the shield busbar at the entry point
into the cabinet. Continue running the cable, still shielded, to the terminal strip or board. No
shields are connected to the terminal strips or boards.
• Serial connecting cables must be shielded. Place the shield on the metallic connector
housing. Also connect the shield to the shield rail. Do not connect the cable shield to a ground
pin of the connector.
• The connector housing and front plate of the boards do not provide adequate cable shielding.
Connect the cable shields at both ends to the shield rails in the cabinets. Always use shielded
analog signal cables, regardless of whether they are installed inside or outside cabinets. In
order to increase the effectiveness of the shielding, ground spare conductors at both ends.
6.8.1

Laying the cable shields

In the case of analog signal lines carrying small signals (mV or µA), attach the cable shield to the
shield bus in the cabinet at one end. In this way you avoid ground loops and line-frequency
interference. You can also connect the open shield end to the enclosure via a radio interference
suppression capacitor (e.g. 0.1 µF 100 V MKT).
6.9 Separating adjacent cabinets using unsuppressed contactors
Do not use any contactors without suppression in the converter cabinets or in cabinets that are
connected to the converter cabinets. All contactors installed in the factory are already equipped
with a suppression circuit. If you use unsuppressed contactors in an adjacent cabinet, you must
partition off the cabinets using a lateral metal plate.
Connect surge suppressors to contactor solenoids that are connected to the same line supply as
the auxiliary power supply of the converter – or are located near the converter (e.g. RC elements,
varistors).
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3rd Party LCI Control Upgrade
Operating Instructions, 02/2022, A5E31872818