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PROTECTIONGenerator ProtectionM‑3430Integrated Protection System for Generators of All SizesUnit shown with optional M‑3930 Target Module and M‑3931 HMI(Human-Machine Interface) Module Microprocessor-based Generator Protection Relay that uses digitalsignal processing technology to provide fifteen protective relayingfunctions Individually programmed input contacts that can be programmedto activate the output contacts. Provides time-targeted information for the 32 most recent events Local and remote communications abilityIndustry Leader Since 1969Made in the USA
M‑3430 Generator Protection Relay – SpecificationProtective Functions Dual-zone phase distance protection for phase fault backup (21)Overexcitation (V/Hz) protection (24)Sensitive dual-setpoint reverse power detection suitable for sequential tripping (32)Dual-zone offset-mho loss-of-field protection (40)Sensitive negative-sequence overcurrent protection and alarming (46)Generator breaker failure protection (50BF)Inadvertent generator energizing protection (50/27)Phase overvoltage (59) and undervoltage (27) protection100% stator ground fault protection (59N/27TN)VT fuse-loss detection and blocking (60FL)Four-step over/underfrequency protection (81)Generator phase differential protection (87)Additional Features Eight programmable outputs and six programmable inputsOscillograph recording32‑target storageMetering of all measured parametersTwo RS-232 and one RS-485 communications portsStandard 19" rack-mount designRemovable printed circuit board and power supplyBoth 50 and 60 Hz models availableBoth 1 and 5 A rated CT inputs availableAdditional trip inputs for externally connected devicesM‑3800A IPScom Communications SoftwareS-3400 IPScom Communications Software for Windows 7 or laterIRIG-B time synchronizationIncludes MODBUS and BECO 2200 protocolsOptional Features Redundant power supplyM‑3930 Target ModuleM‑3931 Human-Machine Interface (HMI) ModuleM‑3801D IPSplot Plus Oscillograph Analysis Software4-Wire RS-485 Connection–2–
M‑3430 Generator Protection Relay – SpecificationSTANDARD PROTECTIVE ntAccuracy†Phase Distance (dual-zone mho characteristic)0.1 to 100.0 Ω0.1 Ω(0.5 to 500.0 Ω) 0.1 Ω or 5%( 0.5 Ω or 5%)–100.0 to 100.0 Ω0.1 Ω(–500.0 to 500.0 Ω) 0.1 Ω or 5%( 0.5 Ω or 5%)Circle Diameter #1, #221Offset #1, #23φImpedance Angle #1, #20 to 90 1 1 to 8160 Cycles1 Cycle100 to 200%1% 1%30 to 8160 Cycles1 Cycle 25 CyclesInverse Time #1–#4——100 to 200%1% 1%1 to 1000 to 910.1——1 to 999 Sec.(from threshold of trip)1 Sec. .06 Sec. or 1%Time Delay #1, #2 1 –1 to 3 Cycles or 1%Volts / HzDefinite TimePickup #1, #2Time Delay #1, #224Inverse TimeCharacteristic Curves3φPickupTime Dial: Curve #1Time Dial: Curves #2–#4Reset RateThe percent pickup is based on nominal VT secondary voltage and nominal system frequency settings.The pickup accuracy stated is only applicable from 10 to 80 Hz, 0 to 180 V, and 100 to 150% V/Hz.RMS UndervoltagePickup #1, #25 to 200 V1V273φTime Delay #1, #21 to 8160 Cycles1 Cycles 0.5 V or 0.5% 0.8 V or 0.75%* 20 Cycles or 1%*** When both RMS and line-ground to line-line is selected.** When RMS (total waveform) is selected, timing accuracy is 20 cycles or 1%; when DFT (fundamental RMS) isselected, accuracy is -1 to 3 cycles or 1%.Third-Harmonic Undervoltage, Neutral27TNPickup #1, #20.3 to 20.0 V0.1 V1 to 8160 Cycles1 Cycle5 to 200 V1V 0.5 V or 0.5%0.002 to 3.000 PU0.001 PU 0.002 PU or 2%0.001 PU 0.002 PU or 2%1 Cycle 16 Cycles 1%Time Delay #1, #227 Undervoltage Inhibit32(positive sequence)Underpower Inhibit 0.5 V–1 to 3 Cycles or 1%Directional Power323φPickup #1, #2 ‑3.000 to 3.000 PUTime Delay #1, #21 to 8160 CyclesThe per-unit pickup is based on nominal VT secondary voltage and nominal CT secondary currentsettings.†Select the greater of these accuracy values.Values in parentheses apply to 1 A CT secondary rating.–3–
M‑3430 Generator Protection Relay – SpecificationSTANDARD PROTECTIVE FUNCTIONS Accuracy†Loss of Field (dual-zone offset-mho characteristic)0.1 to 100.0 Ω0.1 Ω(0.5 to 500.0 Ω) 0.1 Ω or 5%( 0.5 Ω or 5%)-50.0 to 50.0 Ω0.1 Ω(-250.0 to 250.0 Ω) 0.1 Ω or 5%( 0.5 Ω or 5%)Circle Diameter #1, #2Offset #1, #2403φTime Delay #1, #21 to 8160 Cycles1 Cycle–1 to 3 Cycles or 1%Voltage Control(positive sequence)5 to 200 V1V 0.5 V or 0.5%Directional ElementFixed at -13 ——Voltage control for each zone can be individually enabled.Negative Sequence OvercurrentDefinite TimePickup3 to 100%1%Time Delay1 to 81601 CycleInverse TimePickup3 to 100%1%46Time Dial Setting(K I22t) 0.5% of 5 A( 0.5% of 1 A)–1 to 3 Cycles 0.5% of 5 A( 0.5% of 1 A)1 to 951600 to 65,500 Cycle1 Cycle4 minutes(from threshold of trip)——0.50 to 15.00 A(0.10 to 3.00 A)0.01 A 0.1 A or 2%( 0.02 A or 2%)40 to 130 V1V 0.5 VPickup Time Delay1 to 8160 Cycles1 Cycle–1 to 3 Cycles or 1%Dropout Time Delay1 to 8160 Cycles1 Cycle–1 to 3 Cycles or 1%0.10 to 10.00 A(0.02 to 2.00 A)0.01 A 0.1 A or 2%( 0.02 A or 2%)Neutral CurrentPickup0.10 to 10.00 A(0.02 to 2.00 A)0.01 A 0.1 A or 2%( 0.02 A or 2%)1 to 8160 Cycles1 CycleDefinite MaximumTime to TripReset Time (Linear) 3%–1 to 3 Cycles or 1%Pickup is based on the nominal CT secondary current.Inadvertent Energizing50 OvercurrentPickup50/273φ27 UndervoltagePickupBreaker Failure50BF-PhPhase CurrentPickup50BF3φ50BF-NTime Delay–1 to 3 Cycles or 1%50BF can be initiated from designated output contacts or status inputs.†Select the greater of these accuracy values.Values in parentheses apply to 1 A CT secondary rating.–4–
M‑3430 Generator Protection Relay – SpecificationSTANDARD PROTECTIVE FUNCTIONS Accuracy†RMS OvervoltagePickup #1, #25 to 200 V1V593φTime Delay #1, #21 to 8160 Cycles1 Cycle 0.5 V or 0.5% 0.8 V or 0.75%* 20 Cycles or 1%*** When both RMS and line-ground to line-line is selected.** When RMS (total waveform) is selected, timing accuracy is 20 cycles or 1%; when DFT (fundamental RMS) isselected, accuracy is -1 to 3 cycles or 1%.RMS Overvoltage, Neutral59NPickup #1, #2Time Delay #1, #25.0 to 200.0 V0.1 V1 to 8160 Cycles1 Cycle 0.5 V or 0.5%–1 to 3 Cycles or 1%VT Fuse-Loss Detection60FLA VT fuse-loss condition is detected by using the positive and negative sequence components of thevoltages and currents. VT fuse-loss output can be initiated from internally generated logic or frominput contacts.Time Delay1 to 8160 Cycles1 Cycle50.00 to 67.00 Hz40.00 to 57.00 Hz*0.01 Hz2 to 65,500 Cycles1 Cycle–1 to 3 Cycles or 1%FrequencyPickup #1,#2,#3,#481Time Delay #1,#2,#3,#4 0.02 Hz–2 to 3 Cycles or 1%The pickup accuracy applies to 60 Hz models at a range of 57 to 63 Hz, and to 50 Hz models at a range of 47 to 53Hz. Beyond these ranges, the accuracy is 0.1 Hz.* This range applies to 50 Hz nominal frequency models.Phase Differential CurrentMinimum Pickup873φ0.20 to 3.00 A0.01 A(0.04 to 0.60 A)Percent Slope1 to 100%Time Delay1%1 to 8160 Cycles1 Cycle 0.10 A or 5%( 0.02 A or 5%) 2%–1 to 3 Cycles or 1%When a time delay of 1 cycle is selected, the response time is less than 1 /2 cycles.1External FunctionsEXTTwo functions are provided for externally connected devices to trip through the M‑3430 to provideadditional logic and target information. Any one or more of the input contacts (INPUT1 throughINPUT6) can be programmed to activate designated output contacts after a selected time delay.Time Delay #1, #21 to 8160 Cycles1 Cycle–1 to 3 Cycles or 1%Nominal SettingsNominal VoltageNominal CurrentVT ConfigurationSeal-In Delay60 to 140 V1V—0.50 to 6.00 A0.01 A—Line to Line/Line to Ground/Line to Ground to Line to Line2 to 8160 Cycles1 Cycle–1 to 3 Cycles or 1%When Line-Ground to Line-Line is selected, the relay internally calculates the line-line voltage from the line-groundvoltages for all voltage-sensitive functions. This Line-Ground to Line-Line selection should only be used for a VTnominal secondary voltage of 69 V (not 120 V).†Select the greater of these accuracy values.Values in parentheses apply to 1 A CT secondary rating.–5–
M‑3430 Generator Protection Relay – SpecificationMeteringThe M‑3430 provides metering of voltages (phase, neutral and sequence quantities), currents (phase, neutraland sequence quantities), real power, reactive power, power factor and impedance measurements.Metering accuracies are:Voltage: 0.5 V or 0.5%, whichever is greater 0.8 V or 0.75%, whichever is greater (when both RMS and Line-Ground to Line-Lineis selected)Current:5 A rating, 0.1 A or 3%, whichever is greater1 A rating, 0.02 A or 3%, whichever is greaterPower: 0.01 PU or 2%, whichever is greater(real and reactive)Frequency: 0.02 Hz (from 57 to 63 Hz for 60 Hz models; from 47 to 53 Hz for 50 Hz models)Oscillograph RecorderThe oscillograph recorder provides comprehensive data recording of all monitored waveforms, storing up to170 cycles of data. The total record length may be configured by user for 1, 2, 3 or 4 partitions. The samplingrate is 16 times the power system nominal frequency (50 or 60 Hz). When armed, the recorder is triggeredeither via the designated status inputs, trip outputs or via serial communications. When armed yet untriggered,the recorder continuously stores waveform data, keeping the most recent data in memory. When triggered,the recorder continues to store data in memory for a user-defined post-trigger delay period.Target StorageA total of 32 targets can be stored. The information will include the function(s) operated, the functions pickedup, input/output contact status, time stamp, timer status, and phase and neutral currents at the time of trip.CalculationsCurrent and Voltage RMS Values: Uses discrete Fourier transform on sampled (16 times per cycle) voltageand current signals to extract fundamental frequency phasors for M‑3430 calculations. RMS phase voltagesfor the 59 and 27 functions (when total RMS is selected), and the 24 function are obtained using the timedomain approach to obtain accuracy over a wide frequency band. When the RMS option is selected, themagnitude calculation is accurate over a wide frequency range (10 to 80 Hz). When the DFT option is selected,the magnitude calculation is accurate near nominal frequency (50 or 60 Hz).Power Input OptionsNominal 110/120/230/240 Vac, 50/60 Hz, or nominal 110/125/220/250 Vdc. UL rating 85 Vac to 265 Vac andfrom 80 Vdc to 288 Vdc. Burden 20 VA at 120 Vac/125 Vdc. Withstands 300 Vac or 300 Vdc for 1 second.Nominal 24/48 Vdc, operating range from 18 Vdc to 56 Vdc. Burden 20 VA at 24 Vdc and 20 VA at 48 Vdc.Withstands 65 Vdc for 1 second.Optional redundant power supply.Sensing InputsFour Voltage Inputs: Rated nominal voltage of 60 Vac to 140 Vac, 60 Hz/(50 Hz optional). Will withstand240 V continuous voltage and 360 V for 10 seconds. Source voltages may be line-to-ground or line-to-lineconnected. Phase sequence ABC/ACB is selectable. Voltage transformer burden less than 0.2 VA at 120 V.Seven Current Inputs: Rated nominal current (IR) of 5.0 A or 1.0 A (optional), 60 Hz/(50 Hz optional). Willwithstand 2IR continuous current and 100IR for 1 second. Current transformer burden less than 0.5 VA at5 A (5 A option), or 0.3 VA at 1 A (1 A option).–6–
M‑3430 Generator Protection Relay – SpecificationStatus Input ContactsThe status inputs, INPUT1 through INPUT6, can be programmed to block any of the M‑3430 functions andto trigger the oscillograph recorder. The status inputs should be dry contacts and are internally connected(wetted) to a 24 Vdc power supply. To provide breaker status LED indication on the front panel, the INPUT1status input contact must be connected to the 52b breaker status contact. The minimum current value toinitiate/pickup an Input is 25 mA.Output ContactsThe eight programmable output contacts (six form ‘a’ and two form ‘c’), the power supply alarm output contact(form ‘b’), and the self-test alarm output contact (form ‘c’) are all rated as per IEEE C37.90 (See Tests andStandards section for details).Any of the M‑3430 functions can be individually programmed to activate any one or more of the eight programmable output contacts.Target/Status Indicators and ControlsThe RELAY OK LED reveals proper cycling of the microcomputer. The BRKR CLOSED LED will turn onwhen the breaker is closed (when 52b contact input is open). The OSC TRIG LED indicates that oscillographicdata has been recorded in the unit's memory. The TARGET LED will turn on when any of the relay functionsoperate. Pressing and releasing the TARGET RESET button resets the TARGET LED if the conditionscausing the operation have been removed. Holding the TARGET RESET button displays the present pickupstatus of the M‑3430 functions. The PS1 and PS2 LEDs will remain on as long as power is applied to theunit and the power supply is operating properly.CommunicationCommunications ports include rear panel RS‑232 and RS-485 ports, a front panel RS-232 port, and anIRIG-B port. The communications protocol implements serial, byte-oriented, asynchronous communication,providing the following functions when used with the Microsoft Windows-compatible M‑3800A or S‑3400(Windows 7 or later) IPScom Communications Software package. MODBUS and BECO 2200 protocolsare supported, providing: Interrogation and modification of setpointsTime-stamped trip target information for the 32 most recent eventsReal-time metering of all quantities measuredDownloading of recorded oscillographic data (Not available with MODBUS)IRIG-BThe M‑3430 can accept a modulated IRIG‑B time clock synchronization signal through a BNC connectorprovided at the rear of the unit. The IRIG‑B time synchronization information is used to correct the hour,minute, seconds and milliseconds information.HMI Module (optional)Local access to the M-3430 is provided through an optional M-3931 HMI (Human-Machine Interface)Module, allowing for easy-to-use, menu-driven access to all functions via six buttons and a 2-line by24 character alphanumeric LCD. The module connects quickly to the M-3430 Generator Protection.HMI module features include: User-definable access codes allow three levels of securityInterrogation and modification of setpointsTime-stamped trip target information for the 32 most recent eventsReal-time metering of all quantities measured–7–
M‑3430 Generator Protection Relay – SpecificationTarget Module (optional)An optional M-3930 Target Module provides 24 target and 8 output LEDs. Appropriate target LEDs will lightwhen the corresponding M‑3430 function operates. The targets can be reset with the TARGET RESETpushbutton. The OUTPUT LEDs indicate the status of the programmable output contacts.Type Tests and StandardsThe M‑3430 Generator Protection relay complies with the following type tests and standards:Voltage WithstandDielectric WithstandIEC 255-53,500 Vdc for 1 minute applied to each independent circuit to earth3,500 Vdc for 1 minute applied between each independent circuit1,500 Vdc for 1 minute applied to IRIG-B circuit to earth1,500 Vdc for 1 minute applied between IRIG-B to each independent circuitImpulse VoltageIEC 255-55,000 V pk, /- polarity applied to each independent circuit to earth5,000 V pk, /- polarity applied between each independent circuit1.2 by 50µs, 500 ohms impedance, three surges at 5 second intervalsInsulation ResistanceIEC 255-5 40 MegaohmsElectrical EnvironmentElectrostatic Discharge TestIEC 1000-4-2Class 4 (8 kV) – point contact dischargeFast Transient Disturbance TestsIEC 1000-4-4Class 4 (4 kV, 2.5 kHz)Surge Withstand CapabilityIEEE C37.90.12,500 V pk-pk oscillatory applied to each independent circuit to earth2,500 V pk-pk applied between each independent circuit5,000 V pk Fast Transient applied to each independent circuit to earth5,000 V pk Fast Transient applied between each independent circuitRadiated SusceptibilityIEEE C37.90.225-1000 Mhz @ 35V/mOutput Contacts RatingsIEEE C37.90UL 50830 A make for 0.2 seconds at 250 Vdc resistive8 A carry at 120 Vac, 50/60 Hz6 A break at 120 Vac, 50/60 Hz0.1 A break at 125 Vdc0.1 A break at 120 Vac–8–
M‑3430 Generator Protection Relay – SpecificationAtmospheric EnvironmentTemperatureIEC 68-2-1IEC 68-2-2IEC 68-2-3Cold, -20 C for 96 hoursDry Heat, 70 C for 96 hoursDamp Heat, 40 C @ 93% RH, for 96 hoursMechanical EnvironmentVibrationIEC 255-21-1Vibration response Class 1, 0.5 gVibration endurance Class 1, 1.0 gCompliancecULus‑Listedper 508– NRGU.E128716 Industrial Control Equipment– NRGU7.E128716 Industrial Control Equipment Certified for CanadaCAN/USA C22.2 No. 14‑M91cULus‑Listedper 508A – Table SA1.1 Industrial Control PanelsExternal ConnectionsM‑3430 external connection points are illustrated in Figures 1, 2, and 3 on the following pages.PhysicalSize: 19.00" wide x 5.21" high x 10.00" deep (48.3cm x 13.2cm x 25.4 cm)Mounting: The unit is a standard 19", semiflush, three-unit high, rack-mount panel design, conforming toANSI/EIA RS-310C and DIN 41494 Part 5 specifications. Vertical mounting is also available.Contact Beckwith Electric for optional GE L‑2/Westinghouse FT‑41 retrofit panel vertical mounting details.Environmental: For flat surface mounting on a Type 1 enclosure, rated to 70 C surrounding air ambient.Approximate Weight: 13 lbs (5.9 kg)Approximate Shipping Weight: 15 lbs (6.8 kg)Patent & WarrantyThe M‑3430 Generator Protection Relay is covered by U.S. Patents 5,592,393 and 5,224,011.The M‑3430 Generator Protection Relay is covered by a five year warranty from date of shipment.Specification is subject to change without notice.–9–
–10–424344IN347491315IC1A ,NO M50165253171956205266118 - 5 6V8 5 - 2 6 5V60-PS 2 463-18 - 5 6V8 5 - 2 6 5V62 293F3F130SERIAL NO.28PS127OUT PUT S25311F233PS134F43 A MP,MP 2 5 0 V ( 3 A B)PS2232FIELD GND connection is intended for future use.596247.58Ic23The self-test relay is energized when the relay has performed all self-tests successfully.57226.Ib721The power supply relay (P/S) is energized when the power supply is functioning properly.5 A ,NO M55External ConnectionsIa81854RAT ED C URRENT51INS ELF- T EST14A LA RMSP/ S12U.S. PATENT 5,592,393, 5,224,01148IBINRT NFigure 146IA!115.VN10IN1(5 2b)45IN2INPUT SIN49All relays are shown in the de-energized state.5 0 / 6 0 HzRA T ED V O L T A GE6 0 - 140V41IN584.40IN67ONLY dry contacts must be connected to inputs (terminals 5 through 10 with 11 common) because these contact inputs are internally wetted.Application of external voltage on these inputs may result in damage to the units.39VC VC ATX63.38VB CVB-RS 4 8 5COM 3 5FIRMWARE:To comply with UL listing requirements, terminal block connections must be made with #22–12 AWG solid or stranded copper wire inserted inan AMP #324915 (or equivalent) connector. Wire insulation must be rated at 75 C minimum. Terminal block connections 1 through 34 must betightened to 12 in‑lbs torque. Terminal block connections 35 through 63 must be tightened to 8.0 in‑lbs, minimum, 9.0 in-lbs, maximum torque.Over torquing may result in terminal damage.37ARX460 Hz2.36VVA B-350 HzMODEL:Output contacts #1 through #4 are high speed operation contacts.35COM 2RS 2 3 22W A RNING! C O NT A C T W IT H T ERMINA L S MA Y C A US E EL EC T RIC S HO C KDanger! Contact avec les ter minaux peut causer un choc électriqueFO R C O NT A C T RA T INGS S EE INS T RUC T IO N MA NUA L1. NOTES:!IRIG- B16 19 0 118 t h AV E NO .727- 5 4 4 - 23 26L A RGO , FL 3 3 7 7 3BEC KW IT H ELECT RIC CO . INC .M‑3430 Generator Protection Relay – Specification
M‑3430 Generator Protection Relay – SpecificationUtility SystemM-3430 TypicalConnection Diagram52UnitThis function provides control forthe function to which it points.ACBINNOTE: Some functions aremutually exclusive; seeInstruction Book for roundingFigure 2One-Line Connection Diagram–11–
M‑3430 Generator Protection Relay – therRelaysUTILITY er59M-34301052Gen52bThree VT Wye-WyeConnection11ABCOtherRelays1Two VT Open-DeltaConnection1M-343050514849464742 4340 4138 3942 43M-343040 4138 39M-3430GeneratorOtherRelaysABCAlternate VT connectionsRequired generator breaker status input (52b).Contact is closed when generator breaker is open.Use unit breaker contact if no generator breaker present.Output contact pairs designated by user.Alarm output can be grouped to a single alarm atdiscretion of user.Available control output to supervise other relaysfor VT Fuse Loss can be designated.Input contact number is designated by user.WARNING: ONLY dry contacts must be connectedbecause these contact inputs are internally wetted.Application of external voltage on these inputs may resultin damage to the units.NOTE: M-3430 current terminal polarity marks ( ) indicate"entering" current direction when primary current is "from"the generator. If CT connections differ from those shown,adjust input terminals.M-3430585956575455M-34304544Example of Control / Output Connections DC:M-3430 24 V48 VPOWER 60 62SUPPLY 61 63 11OR-DC: 110 V125 V220 V250 VAC: 110 V120 V230 V240 LUREALARMPOWER OKSTATUSALARMVTFUSELOSS52G52Ga4EXTERNAL INPUTSFigure 3ALARM OUTPUTSThree-line Connection Diagram–12–CONTROLOUTPUTSTRIP OUTPUT
M‑3430 Generator Protection Relay – .23]ACTUAL5.28[13.41]RECOMMENDED CUTOUT WHEN RELAY ISNOT USED AS STANDARD RACK 51]0.35[0.89]0.40 [1.02] X 0.27[0.68] Slot (4X)2.25[5.72]1.48[3.76]Standard 19" Horizontal Mount ChassisNOTE: Dimensions in brackets are in centimeters. NOTE: Panels for vertical mounting are available. When mounted vertically, the target module will belocated at the top and all front-panel text will be horizontally aligned. Consult the factory for details.Figure 4Horizontal Mounting Diagram–13–
M‑3430 Generator Protection Relay – ]6.19[15.7]2.25[5.72]0.35[0.89]1.97[5.0]0.28 [0.71]Dia. S18.30[46.51]OUT 1OUT 3OUT 5OUT 7OUT 2OUT 4OUT 6OUT PS 2PS 1TARGETDIAGBRKRCLOSEDOSC.TRIGRELAYOKTIMESYNCCOM 117.50[44.45]Recommended cutout when relay is not used asstandard rack mount and is panel cut out mounted.10.20[25.91]19.00[48.26]NOTE: Dimensions in brackets are in centimeters.Figure 5Vertical Mounting Diagram–14–
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BECKWITH ELECTRIC CO., INC.6190 - 118th Avenue North Largo, Florida 33773-3724 U.S.A.PHONE (727) 544-2326 FAX (727) electric.comISO 9001:2015 1993 Beckwith Electric Co. All Rights Reserved.Printed in U.S.A.800-3430-SP-12MC106/20
When Line-Ground to Line-Line is selected, the relay internally calculates the line-line voltage from the line-ground voltages for all voltage-sensitive functions. This Line-Ground to Line-Line selection should only be used for a VT nominal secondary voltage of 69 V (not 120 V). 59N 60 FL EXT 59 3φ 3φ 87 † Select the greater of these .
