Specifications

Chapter9EMCVFD‐G7SeriesFrequencyInverterOperationManual
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bevulnerableto interference and malfunction, so proposethe following solution: try
to stay away from Interference source; do not make signal lines and power lines
parallel arranging, especiallyparallel banding together; signal lines and power lines
use shielded cables, and is properly grounded; install the ferrite bead (select the
suppression
frequency'srangein30~1000MHz),intheoutputsideofdriveandaround
2to3turns,inthecaseofbad,canchooseEMCoutputfilter;
B. When disturbed devices and the drive use the same power, resulting in conducted
interference, if the above methods can not eliminate the interference,
EMC filter
should be installed between the drive and power ( please refers to 9.3.6 about
selectionofthetype);
C.Peripheralsgroundalone,canruleoutwhencommongroundtogenerateinterference
forthedrive'sgroundwirehavingleakage.
9.3.5 Leakage current and its processing system
When use drive, there are two kinds of leakage current: one is the leakage current to
ground;theotheristheleakagecurrentbetweenlineandline.
A.Influencingfactorsoftheearthleakagecurrentandsolutions:
Thereisdistributingcapacitancebetweentheconductorandtheearth,thedistributing
capacitanceis
greater,leakagecurrentincreases;reducethedistancebetweenthedrive
andmotortoeffectivelyreducedistributingcapacitance.Carrierfrequencyishigher,the
leakage current is greater; reduce the carrier frequency to reduce leakage current.
However,reducingcarrierfrequencywillleadmotor'snoisetoincrease,theinstallation
ofthereactorisalso
aneffectivewaytosolvetheleakagecurrent.
Leakage current increases with the loop current increasing, so the motor power is
larger,theleakagecurrentislarger.
B.Influencingfactorsoftheleakagecurrentbetweenlineandlineandsolutions:
Existdistributingcapacitancebetween thedrive'soutputwiring,ifthecurrent
through
thelinehashighorderharmonic,itmaycauseresonanceandgenerateleakagecurrent.
thethermalrelaywillbemalfunction.