If placing the shield on a mounting plate, use a metal plate because the shield currents must be conveyed back to the
frequency converter. Ensure good electrical contact from the mounting plate through the mounting screws to the frequency
converter chassis. When unshielded cables are used, some emission requirements are not complied with, although the
immunity requirements are observed.
To reduce the interference level from the entire system (unit and installation), make motor and brake cables as short as
possible. Avoid placing cables with a sensitive signal level alongside motor and brake cables. Radio interference higher than
50 MHz (airborne) comes from the control electronics. For more information on EMC, see
chapter 9.5 EMC Recommendations
.
9.2 EMC Test Results
The following test results have been obtained using a frequency converter (with options if relevant), a shielded control
cable, a control box with potentiometer, motor shielded cables, and a motor.
RFI filter type
Conducted emission
Radiated Emission
Standards and
requirements
1)
EN/IEC 61800-3
Category C2
Category C3
Category C2
Category C3
P2, P4 (FC 302)
No
150 m
No
Yes
P6, P8 (FC 302)
150 m (492 ft)
150 m (492 ft)
Yes
Yes
Table 9.1 EMC Test Results (Emission and Immunity)
1) An external RFI filter is required to meet the C2 category.
WARNING
This type of power drive system is not intended to be used on a low-voltage public network that supplies domestic
premises. Radio frequency interference is expected if used on such a network, and supplementary mitigation measures
may be required.
The frequency converter meets the emission requirement for C3 category with 150 m (492 ft) shielded cable. In order to
meet the C2 category requirement, an external RFI filter is required.
shows the electrical diagram of the RFI filter that was used to qualify the frequency converter. In this scenario,
the RFI filter is isolated from the ground, and the RFI relay is disabled using
parameter 14-50 RFI Filter
.
The attenuation factor for the RFI filter is provided in
.
EMC and Harmonics
VLT
®
Parallel Drive Modules
90
Danfoss A/S © 6/2016 All rights reserved.
MG37N102
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