Use Of Emc-Correct Cables - Danfoss VLT AutomationDrive FC 300 Design Manual

FC 300 Design Guide

Use of EMC-Correct Cables

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Danfoss recommends braided shielded/armored cables to optimize EMC immunity of the
control cables and the EMC emission from the motor cables.
The ability of a cable to reduce the incoming and outgoing radiation of electric noise depends
on the transfer impedance (Z
transfer of electric noise; however, a shield with a lower transfer impedance (Z
effective than a shield with a higher transfer impedance (Z
Transfer impedance (Z
transfer impedance (Z
Transfer impedance (Z
The conductibility of the shield material.
-
- The contact resistance between the individual shield conductors.
The shield coverage, i.e. the physical area of the cable covered by the shield -
-
often stated as a percentage value.
Shield type, i.e. braided or twisted pattern.
-
Aluminum-clad with copper wire.
a.
b. Twisted copper wire or armored steel wire cable.
Single-layer braided copper wire with varying
c.
percentage shield coverage.
This is the typical Danfoss reference cable.
d. Double-layer braided copper wire.
Twin layer of braided copper wire with a
e.
magnetic, shielded/armored intermediate layer.
Cable that runs in copper tube or steel tube.
f.
g. Lead cable with 0.043 in. (1.1 mm)
wall thickness.
108
How to Install
). The shield of a cable is normally designed to reduce the
T
) is rarely stated by cable manufacturers but it is often possible to estimate
T
) by assessing the physical design of the cable.
T
) can be assessed on the basis of the following factors:
T
MG.33.B3.22 - VLT is a registered Danfoss trademark
) value is more
T
).
T