Danfoss VLT CDS 303 Operating Instructions Manual

Also see for VLT CDS 302: Troubleshooting Operating instructions

Contents

Danfoss VLT CDS 303 Operating Instructions Manual Manual pdf 28 page image

3.3.12 Electrical Installation - EMCProtectionThe following is a guideline to good engineering practicewhen installing frequency converters. To comply with EN61800-3 First environment, follow these guidelines. If theinstallation is in EN 61800-3 Second environment, i.e.industrial networks, or in an installation with its owntransformer, deviation from these guidelines is allowed, butnot recommended.Good engineering practice to ensure EMC-correctelectrical installation• Use only braided screened/armored motorcompressor cables and braided screened/armoredcontrol cables. The screen should provide aminimum coverage of 80%. The screen materialmust be metal, not limited to but typicallycopper, aluminum, steel, or lead. There are nospecial requirements for the mains cable.• Installations using rigid metal conduits are notrequired to use screened cable, but the motorcompressor cable must be installed in conduitseparate from the control and mains cables. Fullconnection of the conduit from the frequencyconverter to the motor compressor is required.The EMC performance of flexible conduits varies alot and information from the manufacturer mustbe obtained.• Connect the screen/armor/conduit to ground atboth ends for motor compressor cables as well asfor control cables. In some cases, it is not possibleto connect the screen in both ends. If so, connectthe screen at the frequency converter. See alsochapter 3.3.11 Electrical Installation, Control Cables.• Avoid terminating the screen/armor with twistedends (pigtails). It increases the high frequencyimpedance of the screen, which reduces itseffectiveness at high frequencies. Use lowimpedance cable clamps or EMC cable glandsinstead.• Avoid using unscreened/unarmored motorcompressor or control cables inside cabinetshousing the frequency converter(s).Leave the screen as close to the connectors as possible.Figure 3.27 shows an example of an EMC-correct electricalinstallation of an IP20 frequency converter.The frequency converter is fitted in an installation cabinetwith an output contactor and connected to a PLC, which isinstalled in a separate cabinet. Other ways of doing theinstallation may have just as good an EMC performance,provided the above guide lines to engineering practice arefollowed. Installing without following the guideline, andusing unscreened cables and control wires do not complywith all emission requirements, although the immunityrequirements are fulfilled.How to Install VLT® Compressor Drives CDS 302/CDS 30326 Danfoss A/S © Rev. 2013-07-03 All rights reserved. MG34M42233