High Voltage Test; Safety Ground Connection; Electrical Installation - Emc Precautions - Danfoss FC 300 Design Manual

FC 300 Design Guide

High Voltage Test

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Carry out a high voltage test by short circuiting terminals U, V, W, L
2.15 kV DC for one second between this short circuit and the chassis.
NOTE
When running high voltage tests of the entire installation, interrupt the mains and
motor connection if the leakage currents are too high.

Safety Ground Connection

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The adjustable frequency drive has a high leakage current and must be grounded appro-
priately for safety reasons according to EN 50178.
The ground leakage current from the adjustable frequency drive exceeds 3.5 mA. To ensure a good
mechanical connection from the ground cable to the ground connection (terminal 95), the cable
cross-section must be at least 0.39 in2 [10 mm2] or 2 rated ground wires terminated separately.

Electrical Installation - EMC Precautions

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The following is a guideline to 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 Second environment, i.e. industrial networks, or in an installation with its own
transformer, deviation from these guidelines is allowed but not recommended. See also paragraphs
CE Labeling, General Aspects of EMC Emission and EMC Test Results.
Good engineering practice to ensure EMC-correct electrical installation:
Use only braided shielded/armored motor cables and braided shielded/armored control cables. The shield
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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 mains cable.
Installations using rigid metal conduits are not required to use shielded cable, but the motor cable
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must be installed in conduit separate from the control and mains cables. Full connection of the
conduit from the drive to the motor is required. The EMC performance of flexible conduits varies
considerably and information from the manufacturer must be obtained.
Connect the shield/armor/conduit to ground at both ends for motor cables as well as for control cables.
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In some cases, it is not possible to connect the shield in both ends. If so, connect the shield at the
adjustable frequency drive. See also Grounding of Braided Shielded/Armored 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 glands instead.
Avoid using non-shielded/unarmored motor or control cables inside cabinets housing
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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
yield just as good 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 are not complied with, although the immunity
requirements are fulfilled. See the paragraph EMC test results.
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How to Install
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