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.comSIEMENSualsMicroprocessor-based Tripping SystemcalPartManStatic Trip Illwww.Electri. .?()'t'i. "()\\\\() \1\\\\SBulletin SG3169-1
.comantMarlPtricaFinally, there's a sensible approachto power system management. Nowyou can monitor, evaluate and controlyour power distribution system- circuitby circuit - with the new generation ofStatic Trip Ill trip units from Siemens.Siemens has harnessed the powerof sophisticated microprocessors tocreate a new family of "smart" tripunits. Trip units that not only provideovercurrent protection, but also com prehensive metering and extendedprotective relaying. And to top it all off,these intelligent trip units can commu nicate all this information to displays atthe breaker or at remote locations.Now you can know, not guess,exact power conditions circuit by cir cuit. Now your trip unit can alert you tochanging load conditions and log spe cific actions to help keep your powersystem on-line. You tell it in straightfor ward engineering language what youwant it to do. And your Static Trip Illtrip unit does it.Nowhere else will you find such acomplete range of protection and con trol, or the unparalleled flexibility fornew and retrof1t applications, in a singlepackage. Only Siemens gives you thefreedom to specify basic overcurrentprotection or a completely integratedpower monitoring and communicationsmodule from one family of trip units.Only Siemens has the Static Trip IllAdvantage.ualsThe Static Trip Ill Advantag ewww.ElecVersatility Simplifies ApplicationThe Static Trip Ill Advantage startswith a family of four basic models thatcovers a full range of applications.Simply pick the options to meet yourspecific requirements. Static Trip Ill versions providebasic overcurrent protectivefunctions. Static Trip IIIC models addcommunications and currentmetering. Static Trip IIICP units add fullpower metering. Static Trip IIICPX devices includeextended protective relaying.RMS Sensing Eliminates NuisanceTripsAs more and more non-linearloads are coming on line, industry isbeing plagued by harmonics-inducednuisance trips. Static Trip Ill trip unitsuse RMS current sensing to properlyinclude the impact of harmonics andkeep your facility up and running.Interchangeability Means Low CostFlexibilityStatic Trip Ill trip units are inter changeable on any frame rating ofSiemens type RL low voltage powercircuit breakers. With Static Trip Ill tripunits, you need fewer spares andstocking of fragile rating plugs is elimi nated. You get maximum applicationflexibility with minimum investment.Intelligence Is PowerYou need to know what's happen ing on critical circuits. Static Trip Ill tripunits capture the real-time, worst caseand diagnostic data you need to effec tively manage your electrical power sys tem. Static Trip Ill trip units can metercurrent, voltage, power and energyconsumption so you can allocate costand reduce utility bills. They canremember minimum and maximum values for each measured parameter tohelp you manage loads and avoidunnecessary tripping.
.comantMartricaComponents Deliver ReliableProtectionSiemens has gone the extra mile toassure reliable protection for yourequipment and personnel. Switchesuse gold-plated contacts. Printed cir cuit boards are conformal coated.Each unit is burned-in. Microprocessor based overcurrent protection circuitsare already time-proven worldwide inthousands of applications.lPLogic Triggers ActionStatic Trip Ill trip units can providealarm and protective relaying functionsbeyond basic overcurrent protection.Trip or alarm operation can be activat ed by setpoints for measured parame ters, such as reverse power for mains,current unbalance for motors or under frequency for generators.ualsCommunication Reduces FootworkStatic Trip Ill trip units can commu nicate valuable real-time, historical andstatus information to wherever youneed it. Review data at the breaker onthe Breaker Display Unit, or tie into afacility-wide ACCESS'" communicationsystem to remotely monitor and con trol your entire electrical distributionsystem 24 hours a day. Get all the lat est facts without time-wasting footwork.www.ElecShadow Curve Provides RedundantProtectionA unique "shadow" time-currentfunction in communicating modelsprovides backup overcurrent tripping.In the unlikely event the primary micro processor fails, your people and equip ment are still protected.Rugged Design Withstands ToughEnvironmentsStatic Trip Ill trip units stand up totough industrial environments. The trip ping system is hardened to withstandelectromagnetic interference, arcing inthe switchgear, radio frequency inter ference or voltage surges in the prima ry or control wiring. All units withstandsurge and fast transient tests specifiedin ANSI C37.90. Five hundred voltsgalvanic isolation exists between thecommunication bus and the trip unit'selectronics so inadvertent contact withother equipment wiring will not com promise protection. And, of course,Static Trip Ill trip units are UL listed.Specify Static Trip Ill Trip UnitsOnly Static Trip Ill trip units fromSiemens give you the broad applica tion flexibility necessary to control andmanage the electrical distribution sys tems of tomorrow- complete inter changeability of trip units amongbreaker frame sizes, RMS sensing,accurate metering, electronic relayingand digital communications.Specify Static Trip Ill trip units fornew and retrofit applications. And putthe Siemens Advantage to work foryou and your clients.
.comProtection For Th e 21 st CenturyOvercurrent ProtectionLong Time ;\lec;ctualload current r y peaknsensing unit.E"'Actualloadcurrent\h"- wwwHarmonics distort the wave shape ofcurrent and can increase its peak value.Normal peak-sensing units are often con fused and may trip, causing nuisance shut downs, or may fail to trip, causing damageto the electrical plant.ualsQ)Ei Short TimeantMtricaSimple, Convenient User InterfaceStatic Trip Ill trip units are designedfor straightforward operation. The frontpanel groups functions together withdescriptive labeling to make propersettings a snap. Settings may besecured with a clear plastic face plate.A liquid crystal display (LCD) clearlyindicates the cause of tripping: OVER LOAD, SHORT CIRCUIT or GROUNDFAULT. A separate watchdog circuitmonitors the protective microproces sor and the word DISABLED is dis played in the unlikely event a programexecution error is detected.Long Time For Thermal ProtectionAll Static Trip Ill trip units includeadjustable long time setting and delayfor overload protection. Elevenadjustable continuous current settingsfrom 0.5 to 1.0 times the current sen sor rating allow the circuit breaker tooperate without tripping. Cumbersomerating plugs are not required.Five time delay bands allow a widerange of adjustment for circuit breakertripping in response to sustained over load conditions. Settings are labeled inseconds delay at six times the longtime current setting for easy coordina tion and are referenced to the mini mum of their time bands.Switchable thermal memory is pro vided as standard. It remembers theheating effects of intermittent over loads and gives an added level of pro tection.arRMS Sensing For True CurrentMeasurementEvery Static Trip Ill trip unit featuresRMS current sensing so you get accu rate protection, not overprotection orunderprotection. RMS sensing mea sures the true heating value of the cur rent wave including harmonic distortionand provides more accurate protectionthan peak-sensing trip units. Nuisancetripping and inadequate thermal pro tection are eliminated.Reliable Self-Powered OperationOvercurrent tripping uses energyfrom the fault current itself to powerthe Static Trip Ill device and release aflux shifting actuator to mechanicallytrip the circuit breaker. No externalpower source is required for overload,short circuit or ground fault protectionon any Static Trip Ill system. Even theLCD targets require no batteries sovaluable information won't be inadver tently lost.lPThe basic overcurrent protectivefeatures of all Static Trip Ill tripping sys tems are designed to meet demandingrequirements of today's and tomor row's electrical power systems. Asmore and more harmonics-producingequipment comes on line, your needfor Static Trip Ill devices will onlyincrease.J. f\.(frj(\\.\Vhealing valueload currentRMSActual loadcurrentTrip sellingSiemens RMS sensing samples theentire current wave shape and calculatesthe effective heating value of the current.RMS sensing properly evaluates distortionon the line, provides accurate load protec tion and avoids unnecessary trips.InstantaneousCurrentShort Time For SelectiveCoordinationShort time pickup and delay canbe specified to provide maximum flexi bility in selectively coordinated sys tems. Short time pickup may be set at2 to 12 times the long time settingselected. This method automaticallycoordinates long time and short timesettings and allows minimum shorttime pickup at all long time settings forlow available fault applications such asemergency generators.Short time delay may be set onany of five bands from .08 to . 40 sec onds to allow time-selective coordina tion with other devices at high shortcircuit current levels. A "Short Time l2t''switch replaces the square knee of thepickup and delay curve with a rampfunction to provide closer coordinationwith thermal magnetic breakers andfuses.Instantaneous Tripping ForMaximum Short CircuitsFault currents exceeding theinstantaneous pickup setting will tripthe circuit breaker without intentionaltime delay. Instantaneous tripping mini mizes equipment damage and allowsapplication of feeder breakers at theirfull interrupting capabilities. The pickupadjustment is from 2 to 15 times the
.comLCD target provides clear readouts withoutbatteries.-------ments easy.ualsTrip functions are grouped to make adjust ------Sealed binary coded switches use gold plated------A dual-function LED confirms proper operation-------tMof communicating versions.All trip units with short time or ground fault can--------,Communicating models provide a port forlPconvenient local data readout.arbe wired into zone interlocking systems.ancontacts for reliable settings.current sensor rating for all circuitbreaker frame sizes, providing com plete interchangeability. Referencingpickup to the current sensor also pro vides the maximum useable rangebetween continuous current andinstantaneous pickup settings to allowfor high efficiency motor inrush currents.lectricaGround Fault ProtectionQ)www.EEi CurrentUnique Ground Fault Sensing MeetsNEGStatic Trip Ill trip units can be spec ified with integral ground fault protec tion to meet a variety of power systemrequirements including three or fourwire residual sensing as well as singlecurrent sensor direct or zero sequencemeasurement. Ground fault pickupsettings are from 20% to 60% of the"ground sensor" rating which is easilydefined for any of these ground faultschemes. For residual sensing, theground sensor rating equals the cur rent sensor rating through 2000A. Aseparate integral 2000A ground sensorwinding is offered for 3200A and4000A sensors so the maximumground fault pickup is limited to 1 200A(2000A X 60%) in compliance with theNEC Article 230-95 for serviceentrance application. This uniquemethod gives you complete trip unitinterchangeability between breakerframes to reduce the need for costlyspares and provide maximum flexibility.Three time delay bands with fixed12t ramp are provided for coordinatedtripping between devices. A memoryfunction protects against intermittentarcing faults.Zone Interlocking MinimizesEquipment DamageZone interlocking for both shorttime and ground fault functions pro vides the quickest opening times whilemaintaining selectivity. Interlocked tripunits share information about a fault'slocation and direct the circuit breakerclosest to the fault to trip at minimumtime delay. Zone interlocking capabilityis standard on all Static Trip Ill deviceswith short time or ground fault.Additional wiring using separate isolat ing couplers and expanders is requiredfor zone interlocking system operation.Siemens Sentron·" series molded casecircuit breakers with Sensitrip Ill tripunits can also be tied in for the maxi mum flexibility in designing your powersystem. A Zone Interlock IN/OUTswitch allows trip units to remain com pletely interchangeable with non-inter locked systems.
.comAccurate Metering with Versatile CommunicationsMetering FunctionsPhase CurrentsAvg Phase CurrentsIIICIIICP optoptlecGround Current'''Neurtral Current'' Avg Phase Voltage"' Line Voltages .EPhase Voltages1'Avg Line VoltagekW kW Hours kW Hours Reverse kVA wkW DemandkVAR kVAR Hours Power Factor Frequency wwualsantMartriModelMeasuredParametersDisplay Data At The Breaker OrRemote LocationTwo communications ports makeStatic Trip IIIC/CP units extremely ver satile. The local port drives a unique,high visibility Breaker Display Unit(BDU). At the touch of a finger, thebright, eight character alphanumericLEOs show the parameter measuredwith its present value. The BDU can bemounted on the front of the circuitbreaker or any nearby compartmentdoor for local readout.An industry standard RS-485 portallows trip units to become part of theACCESS electrical distribution com munication network where data can beread at a Power Monitor' panel or per sonal computer. Network communica tions occur over a shielded twisted paircommunications bus. Each trip unitcontains a real-time clock which canbe periodically synchronized from amaster device on the network foraccurate time stamping of eventsdown to the second.Regardless of which devices areused to display data, operation is keptsimple and straightforward.caEliminate Costly TraditionalMeteringStatic Trip IIIC/CP trip units elimi nate the need for traditional, space wasting analog metering systems andprovide all the advantages of state-of the-art digital technology. The samehigh quality torroidal current sensorsused for protection are used to metercurrents. For the Static Trip IIICP mod els, voltages are input from speciallydesigned PT modules. Additionalinstrument compartment space andassociated wiring are not required.And because all elements have beendesigned to work as one integratedsystem, the resulting accuracy is com parable with separate traditional analoginstrumentation. RMS sensing is usedto account for harmonics and allowcorrect correlation with protective set tings.The powerful metering capability ofStatic Trip IIICP trip units breaks thebarriers of traditional instrumentation togive you valuable information abouthow your system is really operating.Minimum and maximum values foreach measured parameter are storedin nonvolatile memory to capturechanging load conditions. Kilowatthours are integrated separately forreverse power flow so you can adjustfor utility billing and document periodicemergency generator operation. Andkilowatt demand periods are pro grammable to align with utility billingmethods.lPStatic Trip IIIC/CP trip units areprovided with two powerful micropro cessors: one for basic self-poweredovercurrent protection; the second formetering and communications capabil ity. The Static Trip IIIC version metersand communicates phase currents;the CP version meters and communi cates currents, voltages, power andenergy information. Neutral andground current metering is available onboth models.'''Included when ground fault protection specified''' Requires "N" option and neutral current sensor'" Only displayed for four wire systemsSee Protection In Action.There's a wealth of information inStatic Trip IIIC/CP trip units beyondtheir powerful metering capabilities.These intelligent devices monitor andreport status of the protective watch-The BDU is designed for simple opera tion and can be mounted on the circuitbreaker or an adjacent compartment door.Use the arrow keys to scroll through data.Each 11)easured parameter is clearlyidentifiedPress the "Max" key to see the highestrecorded value for any real-time parameter.When a trip occurs, the cause andassociated measured parameters in theunit's trip log are automatically displayed.
.comThe communications microprocessorprovides backup "shadow" protection justabove the overcurrent protectivemicroprocessor's highest settings.ualsShadow Protection ProvidesBackupStatic Trip IIIC/CP trip units deliverdouble protection. The communica tions microprocessor also includes afixed time-current curve just above thecurve defined by the highest overcur rent pickup and delay settings, effec tively providing backup or "shadow"protection. In the unlikely event of aprotective microprocessor failure, yourequipment and people are still protect ed. And tripping operation due to"shadow" protection is recorded in theunit's nonvolatile trip log.triwww.ElecStatic Trip 1/IC/CP trip units maintaintrip log, minimax table and complete con figuration data in nonvolatile memory whichis unaffected by loss of control power. Thetnp log of this trip unit is being interrogatedby a portable personal computer. Trip unitscan be configured prior to being placedinto service in this same way.Trip units communicateusing industry standardRS-485. The IsolatedMulti-Dropw convertorprovides a convenientRS-485 to RS-232interface.Q)Ei antMlParAlarm Output For Early WarningAny of the trip unit's measuredparameters can be set to activate analarm output relay based on pro grammable threshold and delay set points. For example, use the alarmoutput to signal changing load currentconditions before they cause unwantedtrips. The options are up to you. Whilethe alarm output is standard on StaticTrip IIIC and CP models, breaker andcubicle wiring must be specified tomeet your application. Operation of thealarm relay is recorded in the unit'sevent log for remote signaling via thecommunications bus.cadog and overcurrent pickups (includingreturn to normal) so you'll know yourprotection system is functional.Open/closed breaker operation iscounted and reported; even a "Failure"message is recorded if the mechanismexceeds a preset time delay to openafter a trip command is issued.The most recent pickup conditionsare recorded in the trip unit's time stamped event log where they can beread over the communications bus.Tripping events are recorded in theunit's nonvolatile trip log memory alongwith cause and time-stamped currentinformation. With this kind of diagnosticdata, you'll start seeing normal pickupconditions and how long they're activeso you can avoid unnecessary trippingevents. And if an unavoidable tripoccurs, you'll know which phaseswere involved and can correlate timewith other system events to quicklypinpoint the problem.A watchdog circuit constantlymonitors operation of the communica tions microprocessor. The dual-func tion "Comm Watch" LED confirmsmicroprocessor operation as well asactive communication. Should com munications fail, critical protective func tions remain fully operational.Shadow ProtectionCurrentRemote Open/Close/TripOf particular importance where theorderly shutdown of a process isrequired, Static Trip IIIC/CP trip unitscan optionally be wired to open and/orclose an electrically operated circuitbreaker on command from a PowerMonitor unit or ACCESS host PC. Thealarm relay output is used for the "open"command, thereby restricting use forother alarm functions. All open/close/tripcommunication commands are secureto prevent unintended operations.
.comStatic Trip IIICPX Protective Relay FunctionsProtectiveSettingFunctionRangeCurrent UnbalanceVoltage UnbalanceOvervoltage60-660 VReverse PowerOverfrequencylec.ESimply press "Read" to display pickupand delay settings.:- . .:- . ···.0:-: . -· .0-·.···. . ··. .: 0: .-·.00: : : .: .:- .:-··. :·:·00. 0: -.0: : 0-··wwwSetpoints can only be changed afterentering the proper security code.Protective relay setpoints can beaccessed from a Power Monitor panel orpersonal computer. The screen shows pro grammed values along with conftimatiCJn ofactual trip unit settings for reliable setup.Generators5-50 % 5-50 % 60 -660 V50 .0 - 70 .0 Hz 45.0-60 .0 Hz arlP Eliminate Startup GuessworkWith Static Trip IIICPX trip units,you can know circuit conditions andeliminate guesswork. Use the min/maxdata capture and alarm setpoint func tions to record and analyze actualworst case conditions before decidingon trip setpoints. You can programMains I0-2000 kWSecure SetpointsProtective relay setpoints arestored in nonvolatile memory within thetrip unit where they can be accessedusing the local BDU port or remotecommunications bus. Programming ofsettings is password protected. Whiledisplay of setpoint values is available atall times, setpoints can only bechanged by authorized personnel.triProtective relay setpoints can beaccessed using the BDU. The arrow high lights functions that are programmed to trip.MotorstMUnderfrequencyTypical ApplicationsanUndervoltagecaThe Static Trip Ill family includesthe Static Trip IIICPX- "X" for extend ed protective relaying. Static Trip IIICPXtrip units offer the most comprehensivepackage of overcurrent protection,metering, communications and protec tive relaying features available in anintegrated low voltage tripping system.Seven protective relaying functionsare provided, each with its own pro grammable pickup threshold and oneto fifteen second time delay. Traditionalseparate current unbalance, undervolt age, overvoltage, voltage unbalance,reverse power, overfrequency andunderfrequency relays can now bereplaced with one reliable package toreduce panel space requirements,eliminate bulky wiring and save youtime and money. And Static Trip IIICPXunits provide features not even foundin traditional analog relaying like contin uous monitoring, simple programmingin meaningful engineering units andtime-stamped recording of pickup andtripping events.ualsExtended Protective Relaying values, but not activate trip, until typicalsystem operating conditions areknown.Know Trip HistoryStatic Trip IIICPX trip units recordall protective relay pickup and tripevents in internal memory, just as isdone for basic overcurrent protectivefunctions. The three most recent tripevents are maintained in the unit'snonvolatile trip log with time, causeand associated measured values; e.g.voltages are recorded in the case ofvoltage unbalance tripping. With suchdetailed, time-stamped information,problems can be quickly resolved andsteps taken to avoid similar occur rences in the future. .
Functions I Static Trip Ill Model.comIIICIIICPIIICPX optoptoptopt optoptoptoptoptoptoptopt Communications Microprocessor Watchdog Comm Watch LED Backup "Shadow" Protection Trip Log Self- Powered Overcurrent ProtectionRMS SensingSwitchable Thermal MemoryGround Fault ProtectionLCD TargetZone Interlocking "'Retrofit Universal Mounting PackageRS-485 Communications PortoptoptoptTrip Unit Status Indication Breaker Position Indication Breaker Operation Counter optoptoptEvent Log Phase Current Metering Ground Current Metering optoptopt Power Metering Functions Min/Max Power Log arAlarm Relay Output ,,,lPCommunication Open/Close/TripNeutral Current Metering '"Min/Max Current LogExtended Protective Relaying Extended Trip Log trilec.Ewww(I to r) Static Trip Ill trip unit with univer sal mounting package for retrofit applica tion, cat. no. RMS- T!- T-R; basic overcur rent protective model, cat. no.RMS-TSG- TZ; communicating and powermetering model, cat. no. RMS-TSIG-CPwith BOU.'21tMBreaker Display Unit PortIllanProtective Microprocessor WatchdogPickup LEOscaFour models. A world of applica tion flexibility. That's the Static Trip Illfamily of intelligent trip units.It's a given that you need reliableovercurrent protection on every lowvoltage power circuit. Static Trip Ill tripunits deliver that protection.But when you also need to knowthe real-time current values on any cir cuit, specify Static Trip IIIC trip units.There's no need to buy and installstand-alone ammeters, switches andwiring. A Static Trip IIIC trip unit with aBreaker Display Unit satisfies yourneed to know.When you need complete powermetering, specify Static Trip IIICP tripunits and you'll have accurate real-timeand min/max information at the touchof a finger. No longer will you have todedicate additional compartments formetering modules and suffer theexpense of buying, installing and cali brating so many devices.And when you need extended pro tective relaying, specify Static Trip IIICPXtrip units. Again, you'll eliminate theneed for and cost of additional com partment space, wiring and installationof outboard sensors and relays, butyou'll still get the additional protectionyou need.All the reliability, protection andperformance of the Static Trip Ill familyis available for retrofit to almost any lowvoltage circuit breaker from almost anymanufacturer. Now you can apply thispowerful technology where it is neededregardless of the switchgear manufac turer or vintage. The retrofit versionfeatures a universal mounting package.For protection, application flexibili ty, intelligence gathering, communica tions and extended protective relaying,the Static Trip Ill family of trip units willgive you the advantage for years tocome. Specify Static Trip Ill trip units.And put the Static Trip Ill Advantage towork for you.ualsSp ecify Static Trip Ill Trip Units'" Requires additional wiring to meet specific application."' Supports optional Breaker Display Unit accessory.'o) Included when ground fault protection specified.Requires "N" option and neutral current sensor.Open command uses alarm relay output and restricts use for other alarm functions. Closecommand requires electrically operated breaker
.comGuide Form Sp ecificationantMarlPtrilec.EwwwThe alarm output shall be wired to pro vide the following functions (customerto define in text or with circuit dia grams).""Measured parameters shallinclude true RMS real-time andmin/max values of line and phase volt ages, kW, kW demand, kVA andkVAR. The kW demand period shallbe programmable. Power factor, fre quency, kW hours, kW hours reverse,and kVAR hours shall also be mea sured.""The trip units shall include pro grammable tripping setpoints for cur rent unbalance, voltage unbalance,overvoltage, undervoltage, reversepower, overfrequency and underfre quency. Protective function operationshall be recorded in the trip log withcause and associated value at time oftrip.""Trip units shall include long time,short time, instantaneous, ground fault,communications, power metering andextended protective relay functions asshown on the one-line diagramsaccompanying this specification." (Seefigure for recommended symbol.)"A portable test set shall be includ ed for secondary current input testingof trip unit overcurrent protective func tions over their full range of adjust ment. This device shall be capable oftesting a trip device separately ormounted on a circuit breaker, and shallbe capable of exercising the trippingactuator."ualsshort circuit or ground fault. Retentionof target information shall not rely onbatteries. A continuous self-checkingwatchdog circuit shall be provided tomonitor and indicate improper opera tion of the protective microprocessor."(Optional: "Zone interlocking con nections shall be made between feed er and main circuit breakers for shorttime and ground fault functions.")"Communications and meteringfunctions shall be provided using asecond microprocessor and powersupply which also shall provide backupfor the self-powered overcurrent pro tective microprocessor. An LED shallconfirm proper functioning of the sec ond microprocessor. Measuredparameters shall be phase currentsplus ground current when ground faultprotection is specified." (Optional:"Neutral currents shall also be mea sured.")"An industry standard RS-485communications port shall be providedto remotely read real-time andmin/max measured values, monitorbreaker position and trip unit status,interrogate event and trip logs and pro gram trip unit configuration. The portshall contain at least 500V galvanic iso lation between the communicationsbus and trip device protective functioncircuitry. A means shall be provided toperiodically synchronize the trip unit'sinternal clock with a master bus clockso that trip log data is accurately time stamped to within one second. A sep arate communications port shall beincluded for local readout of real-timeand min/max values, interrogation ofthe trip log, and programming of tripunit configuration." (Optional: "A dis play unit shall be provided and shall bemounted on the circuit breaker whereit can be read and operated with thebreaker compartment door closed.The breaker display shall include aneight -character alphanumeric LED dis play and shall be operated using clear ly labeled, sealed membrane keys withstainless steel switch elements.")"A programmable alarm relay out put shall be provided to activate,based on threshold and time delay val ues associated with any of the mea sured parameters. Alarm output oper ation shall be recorded in an event log.caThe following specification can beadded to the appropriate sections oflow voltage switchgear or switchboardspecifications to guarantee importantfeatures and functions of the StaticTrip Ill tripping system are provided.Specifications for related Siemenselectrical distribution communicationssystem components may also beincluded, such as the Power Monitordisplay and monitoring unit andACCESS host computer:"Each low voltage power circuitbreaker shall be equipped with a self powered microprocessor-based tripdevice to sense overload and short cir cuit conditions. Trip devices shall beinterchangeable so that any trip devicecan be used with any frame size circuitbreaker. The device shall measure trueRMS currents. Peak sensing deviceswill not be accepted. All adjustmentsetting switches shall be digitallyencoded type with gold contacts.""The trip device shall include anadjustable long time current settingwith switchable thermal memo
Siemens Sentron·" series molded case circuit breakers with Sensitrip Ill trip units can also be tied in for the maxi mum flexibility in designing your power system. A Zone Interlock IN/OUT switch allows trip units to remain com pletely interchangeable with non-inter www locked systems. . ElectricalPartManuals . com
