12PEFCPEPLC130BB922.12PE PE<10 mmFigure 7.59 Equalizing Cable next to a Control Cable1 Min. 0.025 in2 [16 mm2]2 Equalizing cableTable 7.72 Legend to Figure 7.5950/60 Hz Ground LoopsWith very long control cables, ground loops may occur.Eliminate ground loops by connecting one end of theshield-to-ground with a 100nF capacitor (keeping leadsshort).100nFFCPE PEPLC<10 mm130BB609.12Figure 7.60 Eliminating Ground Loops by Connecting Groundto 100nF CapacitorAvoid EMC Noise on Serial CommunicationThis terminal is grounded via an internal RC link. Usetwisted-pair cables to reduce interference betweenconductors. The recommended method is shown inFigure 7.62.PEFCPEFC130BB923.12PE PE69686169686112<10 mmFigure 7.61 Using Twisted Pair Cables to Reduce Interference1 Min. 0.025 in2 [16 mm2]2 Equalizing cableTable 7.73 Legend to Figure 7.61Alternatively, the connection to terminal 61 can beomitted:PEFCPEFC130BB924.12PE PE6969686812<10 mmFigure 7.62 Reducing Interference by Omitting Terminal 611 Min. 0.025 in2 [16 mm2]2 Equalizing cableTable 7.74 Legend to Figure 7.627.8.4 RFI SwitchLine Power Supply Isolated from GroundIf the adjustable frequency drive is supplied from anisolated line power source (IT line power, floating delta, orgrounded delta) or TT/TN-S line power with grounded leg,the RFI switch is recommended to be turned off (OFF)1) via14-50 RFI 1 on the adjustable frequency drive and 14-50 RFI1 on the filter. For more detail, see IEC 364-3. In OFF, thefilter capacitors between the chassis and the intermediatecircuit are cut off to avoid damage to the intermediatecircuit and to reduce the ground capacity currents(according to IEC 61800-3).If optimum EMC performance is needed or parallel motorsare connected or the motor cable length is above 80 ft [25m], Danfoss recommends setting the 14-50 RFI 1 to [ON].Refer also to the Application Note, VLT on IT Line Power,MN50P. It is important to use isolation monitors that arecapable for use together with power electronics (IEC61557-8).Electrical Installation Design GuideMG34S222 Danfoss A/S © Rev. 2014-02-10 All rights reserved. 2377 7
