Eaton Cutler-Hammer RMS 510 Instructions Manual

Also see for Cutler-Hammer Digitrip RMS 510: Instructions Instructional Leaflet Instruction leaflet

I.L. 29-885B Page 74.2 Long Delay Current SettingThere are eight (8) available Long Delay Settings, asillustrated in Fig. 4.1. Each setting, called 7r” isexpressed as a multiple (ranging from .5 to 1) of the rat-ing plug current (ln).Note: “ lr” is also the basis for the Short-Delay Cur-rent Setting. (See Section 4.4.)allow for the fact that the load circuit temperatureis already higher than normal, due to the prioroverload condition. Each time an overload condi-tion is repeated, the LTM causes the breaker totrip in a time progressively earlier than the “LongDelay Time Setting”. When the load currentreturns to normal, the LTM begins to reset; andafter about 10 minutes it has reset fully, so thatnext Long Delay trip time will again be the “Set-ting” value.In certain applications it may be desirable to dis-able the LTM function. The LTM function can bedisabled by (first opening the breaker and then)removing the Rating Plug (See Figures 1 and 6),and lastly moving the LTM jumper (inside the rat-ing plug cavity, See figure 4.2.1) to its “INAC-TIVE” connection. (You can enable the LTMfunction again any time you wish by moving theLTM jumper back to its original “ACTIVE” con-nection.)'rIr Available SettingsLong DelaySetting frCDx in2 .5,.6,.7,.8,.85,.9,.95,1= 'r0 In Multiples ofRating PlugAmperes (ln)Fig. 4.1 Long Delay Current Settings4.3 Long Delay Time SettingThere are eight (8) available Long Delay Time Settings,as illustrated in Fig. 4.2, ranging from 2 to 24 seconds.These settings are the total clearing times when the cur-rent value equals six (6) times lrRating Plug Cavity Rating Plug Cavity—rvjwK i O Q ©0V 0 00N. \ 0© 0©V © © @8CK3 SCK3o-© ©5CK2 SCK2o- SCK1 :$KIE EA{/"1 1/1"LTM Inactive"Standard from Factory"LTM Active"Fig. 4.2.1 Long Time Memory “LTM” JumperThe action of the LTM is a factor to consider inperforming multiple Long Delay Time tests. (SeeSection 5.4.)2) There is a condition under which the Long DelayTrip LED can erroneously indicate a LDT hasoccurred, even though the breaker is still closed.This can happen when an overload currentmomentarily exceeds the Long Delay CurrentSetting, lr , so that the Long Delay LED flashes“RED” to indicate the overload condition. Then if,at the very moment when the LED is “ON”, theload current would then suddenly drop to a valueless than 10% of the breaker frame (or currentsensor) rating, the trip unit stops functioningwhile the “4bit Latch Chip” (See Fig. 3) is set andthe LED remains Lighted. If the current wouldagain increase to a value above the Long DelayCurrent Setting, lr , and then return to normal, theFig. 4.2 Long Delay Time SettingsNotes:1) In addition to the standard Long Delay ProtectionElement, the Digitrip RMS 510 trip unit also has aLong Time Memory function (LTM), which servesto protect load circuits from the effects ofrepeated overload conditions. If a breaker isreclosed soon after a Long Delay Trip, and thecurrent again exceeds the Long Delay Setting, lnthe LTM automatically reduces the time to trip, toFAT'NEffective May 1997