Danfoss VLT 2800 Design Guide

3.3.8 Use of EMC Compliant Cables
To comply with requirements for EMC immunity of the control cables and EMC emissions for the motor cables, use
screened/armoured cables.
The ability of a cable to reduce the amount of ingoing and outgoing radiation of electric noise depends on the transfer
impedance (Z
T
). The screen of a cable is normally designed to reduce the transfer of electric noise, and a screen with a
lower Z
T
is more effective than a screen with a higher Z
T
.
Z
T
is rarely stated by cable manufacturers, but it is often possible to estimate Z
T
by looking at and assessing the physical
design of the cable.
Z
T
can be assessed on the basis of the following factors:
•
The contact resistance between the individual screen conductors.
•
Screen coverage, i.e. the physical area of the cable covered by the screen. Is often stated as a percentage and
should be no less than 85%.
•
The screen type, i.e. braided or twisted pattern. A braided pattern or closed pipe is recommended.
Illustration 3.18 Cable Comparison
Installation Design Guide
42 Danfoss A/S © Rev. May/2014 All rights reserved. MG27E402
33

Danfoss VLT 2800 Specifications

General

Brand	Danfoss
Model	VLT 2800
Category	DC Drives
Language	English