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SSI700 User Manual EMC
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7.4 Shielded Cable
7.4.1 Requirements for Shielded Cable
The shielded cable must be used to satisfy the EMC requirements of CE marking.
Shielded cables are classified into three-conductor cable and four-conductor cable. If
conductivity of the cable shield is not sufficient, add an independent PE cable, or use a
four-conductor cable, of which one phase conductor is PE cable.
The three-conductor cable and four-conductor cable are shown in the following figure.
To suppress emission and conduction of the radio frequency interference effectively, the
shield of the shielded cable is cooper braid. The braided density of the cooper braid
should be greater than 90% to enhance the shielding efficiency and conductivity, as
shown in the following figure.
The following figure shows the grounding method of the shielded cable.
Figure 7-1 Grounding of the shielded cable
The installation precautions are as follows:
• Symmetrical shielded cable is recommended. The four-conductor shielded
cable can also be used as an input cable.
• The motor cable and PE shielded conducting wire (twisted shielded) should be
as short as possible to reduce electromagnetic radiation and external stray current and
capacitive current of the cable. If the motor cable is over 100 meters long, an output filter
or reactor is required.
• It is recommended that all control cables be shielded.
• It is recommended that a shielded cable be used as the output power cable of
the AC drive; the cable shield must be well grounded. For devices suffering from
interference, shielded twisted pair (STP) cable is recommended as the lead wire and the
cable shield must be well grounded