Advanced Motion Controls 12A8 - Noise Suppression; AC Line Filter; Ferrite Suppression Cores; Inductive Filter Cards

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Integration in the Servo System / Noise Suppression
Noise Suppression
Whiletheabovewiringandgroundingpracticesshouldbesufficienttoreducenoiseand
interferenceissuestoaminimum,insomesystemssizingorotherconstraintsdonotallow
theseguidelinestobeputintouseeffectively.Inthesecases,thebelowitemsprovideextra
meansofnoisesuppression.
AC Line Filter
Itispossiblefornoisegeneratedbythemachineto"leak"ontothemainACpower,andthen
getdistributedtonearbyequipment.Ifthisequipmentissensitive,itmaybeadverselyaffected
bythenoise.AClinefilterscanfilterthisnoiseandkeepitfromgettingontheACpowersignal.
TheACpowerfiltershouldbemountedflatagainsttheenclosureofthesystemusingthe
mountinglugsprovidedonthefilter.Paintshouldberemovedfromtheenclosurewherethe
filterisfittedtoensureeffectivemetaltometalcontact.Thefiltershouldbemountedascloseto
thepointwheretheACpowerenterstheenclosureaspossible.Also,theACpowercableonthe
loadendofthefiltershouldberoutedasfarfromtheACpowercableonthesupplyendofthe
filterandallothercablesandcircuitrytominimizeRFcoupling.
Ferrite Suppression Cores
IfPWMswitchingnoisecouplesontotheencodersignalsorontothesignalground,thena
ferritesuppressioncorecanbeusedtoattenuatethenoise.Takethemotorleadsandwrap
themaroundthesuppressioncoreasmanytimesasreasonablepossible,usually2‐5times.
Makesuretostripbackthecableshieldandonlywrapthemotorwires.Therewillbetwo
wiresforsinglephased(brushed)motorsand3wiresforthreephase(brushless)motors.
Wrapthemotorwirestogetherasagrouparoundthesuppressioncoreandleavethemotor
casegroundwireoutoftheloop.Thesuppressioncoreshouldbelocatedasneartothedrive
aspossible.
Inductive Filter Cards
Inductivefiltercardsareaddedinserieswiththemotorandareusedtoincreasetheload
inductanceinordertomeettheminimumloadinductancerequirementofthedrive.Theyalso
servetocounteracttheeffectsoflinecapacitancefoundinlongcablerunsandinhighvoltage
systems.ThesefiltercardsalsohavetheaddedbenefitofreducingtheamountofPWMnoise
thatcouplesontothesignallines.Thismeanstheycanbeusedinplaceofthesuppression
coresmentionedabove.
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