Eaton Cutler-Hammer Digitrip RMS 510 Instructions Manual

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

AD 33-855-4 Page 173.5 Long Time Memory Functionln addition to the standard Long Delay ProtectionElement, Digikip RMS 510, 610, 810, & 910 TripUnits also have an unpowered Long Time Memoryfunction (LTM), which serves to protect load cir-cuits from the effects of repeated overload condi-tions. lf a Breaker is reclosed soon after a LongDelay Trip and the current again exceeds the LongDelay Setting (lr), the LTM automatically reducesthe time to trip to allow for the fact that the LoadCircuit temperature is already higher than normal,due to the prior overload condition. Each time anoverload condition is repeated, the LTM causes theBreaker to trip in a time progressively earlier thanthe "Long Delay Time Settings". When the LoadCurrent returns to normal, the LTM begins to reset;and after about 10 minutes it has reset fully. There-fore the next Long Delay Trip Time will again be the"Setting" value.ln certain applications, it may be desirable todisable the LTM function. The LTM function can bedisabled by first removing the Rating Plug from theTrip Unit (Figure 3-5a), and then moving the LTMJumper found inside the Rating Plug cavity on theTrip Unit (Figure 3.5b) to its "INACTIVE" connection(Figure 3.5c). You can enable the LTM functionagain at any time by moving the LTM Jumper backto its original "ACTIVE" connection. The action ofthe LTM is a factor to consider in pedormingmultiple Long Delay Time tests as described inSection 8 of this manual.3.6 Discriminator (High lnitial CurrentRelease)When the Digiirip RMS Trip Unit is not equippedwith an adjustable instantaneous protection set-ting, i.e.: types LS or LSG, a Discriminator Circuitis provided. This circuit will prevent the CircuitBreaker from being closed and latched-in on afaulted circuit. The nonadjustable release is presetat eleven (11)times the installed Rating Plugampere rating (ln).The Discriminator is armed only for the first ten (10)cycles following an initial Circuit Breaker closingoperation with a load current exceeding approxi-mately 2O%o of the Circuit Breaker Frame or SensorRating. Should the Load Current through theCircuit Breaker drop to a value less than this, theDiscriminator will re-arm. Once armed, it willremain armed until the Load Current passingthrough the Circuit Breaker exceeds approximately2jyo for 10 cycles. Any trip operation initiated bythe Discriminator will trip the Circuit Breakerinstantaneously. The Discriminator can be selectedby a switch selection on the front ofthe Trip Unit.Code a@ BA cA oA E F H K100 25 30 35 40 50 60 75 100200 50 60 7A ao 100 120 150 2AA250 63 75 a8 100 125 150 188 254300 75 90 105 120 150 140 225 300400 100 120 140 160 200 240 300 400600 150 180 210 240 300 360 450 600800 200 240 280 320 400 4AA 600 8001000 250 300 350 400 500 600 750 10001200 300 360 420 480 600 720 900 12001600 400 440 650 640 800 960 1200 12002000 500 600 700 800 1000 1200 1200 12002400 600 720 840 960 1200 1200 '1200 12003000 750 900 1050 1200 1200 '1200 1200 12003200 800 960 1120 1200 1200 1200 1200 12004000 1000 1200 1200 1204 1200 1200 1200 12005000 1200 1200 1200 1200 1200 1200 1200 1200cRouND FAULT SETTTNGS larUeeneSloooL!J.DJa?aoz-ktol)INotes:lD Except as noied, tolerances on cunent levels are !1oo/o of valuesO For Testing Purposes Only;when using an exle.nalsingle phasecurrentsource lo check low levelground lault currenl seitngs, il isadvisable to use lhe Auxiliary Power l\,4odule (APM). See IESTPBOCEDURES in instruction leallet.O The raiing plug is tor 50 Hz and 60 Hz applicalions-O All tabulated values are based on the use ol a residual sensinqscheme wth lhe same rated cufient sensor in all phaseand neutral conduclors.O CuNes apply trom -20 C to +55 C ambienti lemperalures above 95C cause aulomatic trip.@ wittr zone intertoct on qround iault utilized and no restrainingsignal, the minimum time band @applies -regardless of selting.Fig. 3-4b Digitrip RMS Ground Fault Protection Time-Current Curve (G)Etlective 9/01 ElT.il