The following is a guideline for good engineering practice when installing adjustable frequency drives. Follow these guidelines to comply with EN 61800-3

First environment

. If the installation is in EN 61800-3

from these guidelines is allowed but not recommended. See also paragraphs

Good engineering practice to ensure EMC-correct electrical installation:

•

Use only braided shielded/armored motor cables and braided shielded/armored control cables. The shield should provide a minimum coverage

of 80%. The shield material must be metal, not limited to, but typically, copper, aluminum, steel or lead. There are no special requirements for

the line cable.

•

Installations using rigid metal conduits are not required to contain shielded cable, but the motor cable must be installed in conduit separate from

the control and line cables. Full connection of the conduit from the drive to the motor is required. The EMC performance of flexible conduits

varies greatly, and information from the manufacturer must therefore be obtained.

•

Connect the shield/armor/conduit to ground at both ends for motor cables as well as for control cables. In some cases, it is not possible to

connect the shield at both ends. If so, connect the shield at the adjustable frequency drive. See also

Control Cables

•

Avoid terminating the shield/armor with twisted ends (pigtails). It increases the high frequency impedance of the shield, which reduces its

effectiveness at high frequencies. Use low impedance cable clamps or EMC cable connectors instead.

•

Avoid using unshielded/unarmored motor or control cables inside cabinets housing the drive(s), whenever this can be avoided.

Leave the shield as close to the connectors as possible.

The illustration shows an example of an EMC-correct electrical installation of an IP 20 adjustable frequency drive. The adjustable frequency drive is fitted

in an installation cabinet with an output contactor and connected to a PLC, which is installed in a separate cabinet. Other ways of performing the installation

may result in an equally effective EMC performance, provided the above guidelines for engineering practice are followed.

If the installation is not carried out according to the guidelines, and if non-shielded cables and control wires are used, some emission requirements will

not be fulfilled, although the immunity requirements will be. See the paragraph

Second environment,

i.e., industrial networks, or in an installation with its own transformer, deviation

CE Labeling, General Aspects of EMC Emission

EMC test results

MG.33.BC.22 - VLT

is a registered Danfoss trademark

8 Electrical Installation

and

EMC Test Results

Grounding of Braided Shielded/Armored

8-45