Eaton Cutler-Hammer Digitrip RMS 910 Instructions Manual

Also see for Digitrip RMS 910: Instructions Instructional Leaflet Instruction leaflet

I.L.29-889APage18afteraLongDelayTrip,and the currentagainexceeds theLongDelayCurrentSetting,lr,theLTMautomatically reduces the timetotrip,toallowforthefactthattheloadcircuittemperatureis alreadyhigherthan normal,duetotheprior overload condi-tion.When the loadcurrent returnstonormal,theLTMbeginstoreset;and after about10minutesithas resetfully,sothatnextLongDelaytriptimewillagainbe the“Setting”value.ToresettheLTMquickly,seeSection4.4,item3.label(seeFig.4),andontheapplicable(I)Time-CurrentCurve referenced inSection6.Available"TestAmps"SettingsBreakerTripsat 6TandGFTCD"6T"=PhaseCurrentTestat6xlnandTRIPSbreaker;"1,2,3,8or10"xln=PhaseCurrentTest-NObreakerTRIP;"GFT"=GroundCurrentTestandTRIPSbreaker;"GF"=GroundCurrentTest-NObreakerTRIP.SeeSection4.4.2forinser-vicetesttriplimitations.TestAmps3-’!x In00Test3)OTripnReset®w3.4ShortDelay Current SettingThere are eight(8)availableShortDelay“Pick-up”Cur-rentSettings,asillustratedinFig. 8.3.Sixsettingsare intherangefrom2to6 timeslrandthe othertwosettingsare“S1”or“S2”timeslr.(REMEMBER:lris theLongDelayCurrent Setting).The values that“S1”and“S2”have dependuponthe typeof circuit breaker,andarespecified bothon theratingpluglabel (seeFig.4) and onthe applicable(LS)Time-Current Curvereferenced inSection6.&Push,thenreleasebuttontoresetTripUnit.Required following allautomatictripandtestoperations.'%Push, thenreleasebuttontotest.Testoperationbegins withreleaseofpushbutton.UnitOStatusFig.9IntegralTestPanel(LowerRightCornerof TripUnit)3.7NOInstantaneousCurrentSettingFortypesLS and LSG Trip Units,pleaseseeSections1.1.3Discriminator (High initial CurrentRelease)and1.1.4OVERRIDE(Fixed Instantaneous),foravailablefast-acting high short-circuitprotection.3.8 Ground Fault Current SettingThe eight (8)Ground Fault“Pick-up”CurrentSettingsarelabeled with the code letters“A”through“K”(exceptthere areno “G”or“I”settings),asillustratedinFig.8.6.In general, the specificcurrentsettings range from0.25to 1.0times(ln),the rating plug value,butcannotexceed1200A.ThespecificGround Current Settings foreachletterare listedinTable4 and onthe(G)Time-CurrentCurve applicableforthe circuit breaker(see Section 6).Note:For Testing Purposes Only: When usinganexternal single phase currentsourcetotest low levelground fault current settings,itisadvisabletousethe AuxiliaryPower Module(APM)(See Section1.6andFig.7).3.9Ground Fault Time Delay SettingAs illustrated in Fig.8.7,thereare twodifferent GroundFault curve shapes,i.e., fixed time (flat)andl2tresponse.The shape selected depends on the typeofselectivecoordination chosen.Thel2tresponse will providealonger timedelay in the low-end ofthe ground fault cur-rent range thanwill the flat response.3.5 Short Delay TimeSettingAsillustrated in Fig.8.4,therearetwodifferent ShortDelay curve shapes,i.e.,fixed time(flat)andl2tresponse. Theshapeselected depends on the typeofselective coordinationchosen.Thel2t response will pro-videalonger timedelayinthe low-endofthe short delaycurrentrange thanwillthe flatresponse.Five flat(.1,.2,.3, .4,.5 sec.)andthreel2t (.1*,.3*,.5*sec.)response time delaysettings areavailable.Thel2tresponse settings are identified by thesuffix asterisk(*)thatappears in the setting viewing window.Thel2tresponse isapplicabletocurrentsless thaneight (8)timeslr,the Long Delay Setting.Forcurrents greaterthan 8 timeslr,thel2tresponse reverts to theflatresponse.Note:See also Section 1.1.5,Zone Interlocking,above.3.6 Instantaneous Current SettingThere are eight(8) available Instantaneous Current Set-tings,as illustrated in Fig.8.5.Six settings are in therange from 2to 6 times the rating plug value (ln), and theother two settings are “M1” and“M2”times (ln). The val-ues that“M1”and “M2” have depend upon the type of cir-cuit breaker, and are specified both on the rating plugE;T’N Effective May 1997