User Manual

Receiving and Handling 2-5
1502-UM051E-EN-P – June 2013
eallowableleakagecurrentof5mAisamaximumfornewdryequipment,andis
exclusiveofleakageduetotestequipmentleads.etestsetupleakagecanbe
determinedbyrunningthedielectrictestwithtestleadsnotconnectedtothe
contactorandnotingthemaximumleakagecurrent.Ifthisvalueismorethan
2milliamperes,itshouldbeaddedtothe5mAlimitwhentestingthevacuum
bottles.
NOTE: RockwellAutomationdoesnotrecommendDCHiPottestingbecause
the values obtained during the test are not a reliable indication of vacuum bottle
integrity.
 DCHiPottestingisunreliableduetotheoccurrenceofaphenomenonknown
asCathodeRayTubeEect.isoccurswhenonecontactofthevacuumbottle
hasadeformity,suchasaburrordeposit,whiletheothercontactremainsat
andtrue.issetsupleakagecurrentswhichowfromasmallsurfacetoalarge
surfaceinonedirectionandviceversawhenthepolarityofthetesterischanged.
eresultantcurrentislargeinonedirectionwhichwouldindicate,incorrectly,
a faulty vacuum bottle.
 Atbest,DCtestingwillverifyvacuumintegrityifbothcontactsurfacesare
perfectlysmooth.Itwillnot,however,giveanyindicationofthedegreeofvacuum
sincethecontactsurfacecanfeasiblychangewitheachoperationofthevacuum
contactor.ACtesting,ontheotherhand,willprovidereliablevacuumintegrity
indication.Aswell,thedegreeofvacuumwithinthebottlecanbedeterminedby
comparing initial test results to the present readings. Increases in leakage current
indicatesareductioninvacuumwithinthevacuumbottle.
 Forthesereasons,RockwellAutomationrecommendsACtestingastheonly
reliable method of testing vacuum bottles.
Insulation Resistance Test Usinga1000voltMegger,theresistancefromphasetophaseorphasetoground
shallbegreaterthan500megohms.