MSD Multi-Axis System Operation Manual DC-AC Servo Drive
29
4 Electrical installation
Figure 4.3 Shield connection
•
Do not strip back too far the shield.
•
Shields are not allowed to be used to carry power, e.g. as a substitute for the N
or PE conductor.
•
The shielding effect can be improved by laying in metal ducts/tubes.
•
If it is necessary to lay very large cable cross-sections, instead of shielded
cables it is also possible to lay separate individually shielded wires.
•
Shields must be connected at one end as a minimum. Connection at
multiple points is recommended, otherwise potential equalisation currents
may flow in physically extensive installations. If the e is interference with long
ground connections, these can be connected using coupling capacitors.
These capacitors will provides a high-frequency connection for suppressing
interference without transmitting the 50-Hz components.
•
The usage of tinned, galvanised, aluminised or cadmium-plated elements is to
be preferred over painted components; it will then not be necessary to remove
the paint. Connectors are to be avoided, or several contacts are to be used for
the shield connection in the connector.
For further information on the cross-section of the protective earth conductor see
4.2.4
Shielding measures
You should take into account the following points for the shielding measures:
•
Use only shielded mains, motor and signal cables as shown in Figure 4.1,
. For all shielded connections use cables with double copper
braiding with 60 to 70 % coverage.
•
Connect the shield at both ends using a large area connection. Extending the
shield to the earthing point using a wire (pigtail) reduces the shielding effect by
up to 90 %.
Figure 4.1 CORRECT shield connection
Figure 4.2 INCORRECT shield connection - do not extend to the earthing point (pigtail)
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Id. no.: CA97554-001 0
5
/2017
