GE K-45404F User's Manual
Contents
1. BaD 06 0 0 98 Ed IAVSIK IAVSIK pon vo onn e 0 78 TAV52C 52 0 94 14 NoTaps 048 046 TABLE IIIB GEK 45404 50 Cvcle Burden at Rated Voltages RELAX VOLTAGE TAP SETTINGS VOLT AMPS POWER WATTS TYPES RATINGS FACTOR 1 5 IAVSID IAVSID IAVSIK 52 52 Minimum pickup volts OPERATING CHARACTERISTICS The Type IAV51D relav is a low pickup voltage relav normally used for ground fault protection on AC rotating machines It has single circuit closing contacts that close when the voltage increases to pickup value as set on the tap block The time delay In closing the contacts is determined by the setting of the time dial at the top of the shaft The IAV51D has a capacitor and tapped resistor connected in series with the operating coil The capacitor 15 added to tune the circuit giving a low pickup voltage at rated frequency At rated voltage the operating U magnet is highly saturated increasing the impedance of the circuit thus limiting the current to a safe value The taps on the resistor are connected to the tap block to provide a four to one range of pickup As shown in the tvpical external connection diagram Fig 8 this relav Is connected to the machine neutral potential transformer through a closed contact on the auxiliary tripping relav hence is energized only when ground occurs To obtain still lower pickup than the nor2. ADJUSTING RING DRAG MAGNET FIG 1 8043181 0 TYPE IAV51D RELAY REMOVED FROM CASE FRONT VIEW 18 GEK 45404 PLUG TAP BLOCK CRADLE CAPACITOR GOU AND a MAGNET ASSEMBLY RESISTOR WITH TAPS FIG 2 8043182 0 TYPE IAV51D RELAY REMOVED FROM CASE REAR VIEW 19 GEK 45404 SEA IN INDUCTION ELEMENT ELEMENT FIG 3 6400439 5 INTERNAL CONNECTIONS OF THE TYPE IAV5ID RELAY FRONT VIEW 20 GEK 45404 SEAL IN INDUCTION UNIT UNIT 4 6 SHORT FINGER FIG 4 362A514 3 INTERNAL CONNECTIONS OF THE TYPE IAVSIK RELAY FRONT VIEW 21 GEK 45404 INDUCTION UNIT 6 u SHORT FINGER FIG 5 6556505 0 INTERNAL CONNECTIONS OF THE TYPE IAV52C RELAY FRONT VIEW 22 GEK 45404 _ INDUCTION UNIT 2 SHORT FINGER FIG 6 418A790 0 INTERNAL CONNECTIONS OF THE TYPE IAV52D RELAY FRONT VIEW 23 GEK 45404 INDUCTION UNIT SEAL IN INDUCTION SEREN UNIT li L i x W x lt JO 08i Mo eee FIG 7 0257A8379 0 INTERNAL CONNECTIONS OF THE TYPEIAV52K RELAY FRONT VIEW 24 GEK 45404 UNIT TRANSFORMER GENERATOR LOAD 41 ExT RESISTOR CAP 59 IAV5IK 52 DISTRIBUTION TRANSFORMER TIAV5IK Mr DC IAV52K FIG 8 0275A2004 0 EXTERNAL CONNECTION DIAGRAM OF TYPES IAV51KAND IAV5
3. The 0 2 ampere tap 1s for use with trip coils that operate on currents ranging from 0 2 up to 2 0 amperes at the minimum control voltage If this tap Is used with trip coils requiring more than two amperes there is a possibility that the 7 ohm resistance will reduce the current to so low a value that the breaker will not be tripped The 2 ampere tap should be used with trip coils that take 2 amperes or more at minimum control voltage provided the tripping current does not exceed 30 amperes at the maximum control voltage If the tripping current exceeds 30 amperes an auxiliary relay should be used the connections being GEK 45404 such that the tripping current does not pass through the contacts of the target and seal in coil of the protective relav BURDENS Burdens for the various relay types are give in Tables and B TABLE 60 Cvcle Burdens Rated Voltage RELAX VOLTAGE TAP SETTING VOLT AMPS POWER WATTS TYPES RATING FACTOR IAVSID IAVSID 199 IAV52D IAVSID IAVSIK 52 IAVS2C ILAVSID IAVSID TABLE IIIA CONTINUED GEK 45404 50 Cvcle Burdens at Rated Voltages RELAY VOLTAGE TAP SETTING VOLT AMPS POWER WATTS TXPES RATING FACTOR IAVSID IAVSIK 67 52 IAVS2C Minimum pickup volts TABLE 60 Cycle Burden at Rated Voltages FACTO TYPES RATINGS FACTOR po BS 02 1210609 06 1 096 2 Es Si po 5 fi 0 94 Mavs 809 056 10 98 1 60 509 2 110 113 0 86
4. at a anus ku Su 13 GROEND EONNEEC TON Sa uo sauku la 13 OPERA TO aa 13 IL e n EN RETR MTA 14 Tiroeranad 14 tii rigi keta a da Nota itti a 14 yuaya on ka a n 15 PERIODIC CHECKS AND ROUTINE MAINTENANCE 15 MEN WE WA NE ER 15 DISKA di ik tee bo isti Mea be de DR e ira isti ko epe ba Edit 15 CONTACT CEEANING uzun a tata 16 SEER VIE INC u Sanam if a re esau ded a e aa e Ga a 16 RENEWA B PA YARI ukuna dite a G dia 16 EISFOFIEEUSTRA ON 17 Cover Photo 8043180 These instructions do not purport to cover all details or variations in equipment nor provide for everv possible contingency to be met in connection with installation operation or maintenance Should further information be desired or should particular problems arise which are not covered sufficiently for the purchaser s purposes the matter should be referred to the General Electric Companv To the extent required the products described herein meet applicable ANSI IEEE and NEMA standards but no such assurance is given with respect to lo
5. the operating value Operating voltage for the IAV51D IAV52D IAVSIK and IAV52K relays 15 the minimum voltage for a given tap setting at which the contacts just make 14 GEK 45404 Time Setting The time of operation of the overvoltage relav 16 determined primarily by the setting of the time dial Further adjustment is obtained bv moving the permanent magnet along its supporting shelf moving the magnet in toward the back of the relav decreases the time while moving it out increases the time Fig 11 shows the time voltage characteristics of the IAV51D IAV52D IAVSIK and IAV52K for the four tap settings for the Number 1 5 and 10 time dial positions The time voltage characteristic of the 1AV52C which has no taps 15 the same as for the tap in the D amp K relays To make time settings set the time dial to the number required to give the desired characteristic by turning it until the number lines up with the notch in the adjacent frame The time indicated by the curves 15 the time required to close the relav contacts when the voltage 15 suddenly increased from a value below pickup to the value on the curve expressed in multiples of tap setting The time obtained should be the value on the curve 15 PERIODIC CHECKS AND ROUTINE MAINTENANCE In view of the vital role of protective relays in the operation of a power system it is important that a periodic test program be followed It 15 recognized that the interval between per
6. 0 INTERNAL CONNECTIONS OF THE IAV52C RELAY FRONT VIEW 0418A790 0 INTERNAL CONNECTIONS OF THE TYPE IAV52D RELAY FRONT VIEW 0257A8379 0 INTERNAL CONNECTIONS OF THE TYPE IAV52K RELAY FRONT VIEW O275A2004 0 EXTERNAL CONNECTION DIAGRAM OF TYPES IAV5IK AND IAV52K FOR GENERATOR GROUND FAULT PROTECTION 0275A2003 0 EXTERNAL CONNECTION DIAGRAM OF TYPE IAV5ID AND IAV52C FOR GROUND FAULT DETECTION ON AN UNGROUNDED SYSTEM K6154391 3 TEST CONNECTIONS FOR OVERVOLTAGE RELAYS 0178 8140 0 TIME VOLTAGE CURVES FOR TYPES IAVSID SIK 52D AND S2K RELAYS 8025039 CROSS SECTION OF DRAWOUT CASE SHOWING POSITION OF AUXILIARY BRUSH 0275A4399 0 OUTLINE OF IAV5IK AND IAV52K EXTERNAL CAPACITOR K6209270 2 OUTLINE AND PANEL DRILLING FOR RELAY TYPES IAV51D 52 AND IAV52C K6209271 7 OUTLINE AND PANEL DRILLLING FOR RELAY TYPES IAV51K AND IAV52K 17 GEK 45404 PLUG TARGET SEAL IN UNIT STATIONARY CONTACTS SEAL IN UNIT MOVING ASSEMBLY Tuma AL i t EL a IB gt 1 4 811 OF YE tay ko WO 24 L Li 12 RIGHT sapaq N p FARTA TALE i Madan a Pp kr PIVOT BLOCK TIME DIAL MAIN STATIONARY BRUSH AND CONTACT ASSEMBLY MAIN MOVING CONTACT SPIRAL SPRING SPIRAL SPRING
7. 2K FOR GENERATOR GROUND FAULT PROTECTION 25 GEK 45404 UNGROUNDED SYSTEM ALTERNATE RESISTOR FT m IAV5ID 520 W A tr IAV52C TAVSID 1 52 OR 1 520 D C FIG 9 0275A2003 0 EXTERNAL CONNECTION DIAGRAM OF TYPE IAVSID IAV52C ANDIAV52D FOR GROUND FAULT DETECTION ON AN UNGROUNDED SYSTEM 26 GEK 45404 A C SUPPLY CORRECT FREQUENCY TPOTENTIONETER EXTERNAL L CAPRE TOR T USED ONLY ON TAN silt 2 sek lear gt Ch MF 2 TIMER DEVICE FUNCTION NUMBERS 59 OVERVOLTAGE RELAY TYPE AV SI SEAL IN UNIT WITH TARGET FIG 10 K6154391 3 TEST CONNECTIONS FOR OVERVOLTAGE RELAYS 27 GEK 45404 TIME IN SECONDS m T 1 3 253322 ss its HEEE STICS FI RELAY IZIAWSIDEK umama mam code LI HE kt W LLI 12 14 8 MULTIPLES OF SETTING NOTE TD Time Dial setting FIG 11 0178A8140 0 TIME VOLTAGE CURVES FOR TYPES IAV51D 51K 52D AND 52K RELAYS 28 GEK 45404 CONNECTING PLUG MAIN BRUSH CONNECTING BLOCK AUXILIARY BRUSH TERMINAL BLOCK SHORTING BAR NOTE AFTER ENGAGING AUXILIARV BRUSH CONNECTING PLUG TRAVELS V4 INCH BEFORE ENGAGING THE MAIN B
8. 52K CONNECTIONS Internal connections are shown in Figs 3 to 7 for the various relays GROUND CONNECTIONS One of the mounting studs or screws should be permanently grounded by a conductor not less than No 12 B amp S gage copper wire or its equivalent OPERATION Before the relay is put in service the pickup voltage and time voltage tests described under ACCEPTANCE TESTS ELECTRICAL TESTS should be made to determine that factory adjustments have not been disturbed The relay may be tested while mounted on the panel either from its own or another source of power by inserting a separate testing plug in place of the connecting plug Or the cradle can be drawn out and replaced by another that has been laboratory tested 13 GEK 45404 ADJUSTMENTS Target and Seal in Unit For trip coils operating on current ranging from 0 2 up to 2 0 amperes at the minimum control voltage set the target and seal in tap plug the 0 2 ampere tap For trip coils operating on currents ranging from 2 to 30 amperes at the minimum control voltage place the tap plug in the 2 0 ampere tap The tap plug is the screw holding the right hand stationary contact of the seal in element To change the tap setting first remove the connecting plug Then take a screw from the left hand stationary contact and place it in the desired tap Next remove the screw from the other tap and place it in the left hand contact This procedure is necessary to preve
9. Click here to get to our homepage http www gemultilin com MULTILIN GEK 45404F GE Power Management INSTRUCTIONS OVERVOLTAGE RELAYS TYPES IAV 51D K 52C D K GE Power Management 205 Great Valley Parkway Malvern PA 19355 USA GEK 45404 PpESCRU ON 3 APEC A TWO Na E 4 RACING Sete Si sa i bati ea set tal e e ee at 5 PURDEN at la 6 OFEKATING CHAR ACT ERTS kol bate tu 8 9 RECEIVING HANDLING AND STORAGE 255 tin issues sis 10 RN 10 IANDEING it e A 10 G 10 ACCEPIANCGE TES TS ikla be nt 10 OUR 10 a a 11 CR 12 Ji sol rR IAN AG eta a a t l a kn tp da a aa a a a 12 Power Reqtintement se Gor Billy uu a a la n kutanku a a a a so 12 spol Pp A 12 li YON LO SM L e 12 INSTALECA TION cate u au sana 13 INSPEC NO 13 Www 13 TIC ee bi pe i g 13 CONNECTION acus a Shu e a e a
10. RUSH THE TERMINAL BLOCK FIG 12 8025039 0 CROSS SECTION OF DRAWOUT CASE SHOWING POSITION OF AUXILIARY BRUSH 29 GEK 45404 PLAN VIEW AA 520 MAX_ 425 4125 FRONT VIEW DRILLING PLAN CAPACITOR 024649024 PI200A BRACKET 0302 0920 22 FIG 13 0275A4399 0 OUTLINE OF IAV51K AND IAV52K EXTERNAL CAPACITOR 30 GEK 45404 HANEL LOGATICH SE WH FLUSH SURF ACE hi TG HT6 3 4 18 STUDS OR SURFACE il MTG i fa 9 1 10 32 SCREW L OR STUD NUMBERING OF STUDS MTG il FRONT VIEW QUTLINE 7 feta a aa N 4 MOLES 7 de kull 22 24 lan ak ze Wr 34 l S PANEL DRILLING FOR SEMI FLUSH 45 MOUNTING FRONT VEW i PANEL DRILLING FOR SURFACE MOUNTING FRONT VIEW VIEW SHOWMG ASSEMBLY OF HARDWARE FOR SURFACE MTG ON STEEL PANELS FIG 14 K6209270 2 OUTLINE AND PANEL DRILLING FOR RELAY TYPES IAV31D 52D AND IAV52C 31 GEK 45404 PANEL LOCATION SEMI FLUSH SURF ACE P 5 16 18 STUDS MTG MIG FOR SURFACE MTG 0 C4 10 32 x 3 8 STUD MTG SCREWS NUMBER ING 97531 IL J 4 I x x 10 8 a l x BACK VIEW 1 4 DRILL 9MM F 6 187 g 0 PA pak 157 MM 7T6MM A FE c CUTOUT MAY REPLACE b 15MM DRILLED HOLES 2 187 406 56MM ON T x Eem b 112MM 224MM Ki Ta z
11. a 218 SMM 5 PANEL TYPICAL PANEL DRILLING FOR SEMI FLUSH MOUNTING PANEL DRILLING FRONT VIEW FOR SURFACE MOUNTING FRONT VICW CASE TYPICAL DIM INCHES VIEW SHOWING ASSEMBLY OF HARDWARE MM FOR SURFACE MTG ON STEEL PANELS FIG 15 K6209271 8 OUTLINE AND PANEL DRILLLING FOR RELAY TYPES IAVSIK AND IAV52K 22
12. cal codes and ordinances because they vary greatly OVERVOLTAGE RELAYS TYPES IAVSID IAVSIK IAV52C IAV52D 52 GEK 45404 DESCRIPTION These are single phase sensitive overvoltage relays of the induction disk construction They are equipped with a time dial so as to provide adjustable time delav in their operation The relavs are principallv applicable for sensitive overvoltage ground detection for high impedance grounded generators or for ungrounded power svstems The differences among the four relavs are as indicated in Table A below Each relay 15 mounted in a standard size 51 drawout case and the outline and panel drillings are shown in Figs 14 and 15 Fig 13 shows the outline for an external capacitor when used The internal connections of the relays are indicated in the table Each relay contains a target seal in unit that is used to protect the relay main contacts and control spring from damage due to breaker trip current TABLE A CONTINUOUS PICKUP INTERNAL RATING RANGE TAPS CONTACTS CONNECTIONS VOLTS VOLTS FIGURE IAVSID 10 40 16 64 28 112 IAVSIK 5 4 20 YES INO 2 52 IAV52D Ta a IAVS2K 67 5420 The two normally open contacts a common connection refer to the internal connections of the relav All relays have a 360 volt 10 second rating GEK 45404 APPLICATION These are single phase sensitive time delav overvoltage relavs They are principallv applicable for se
13. e dust and metallic chips Foreign matter collected on the outside of the case mav find its wav inside when the cover is removed and cause trouble in the operation of the relav ACCEPTANCE TESTS Immediatelv upon receipt of the relav an inspection and acceptance test should be made to make sure that no damage has been sustained in shipment and that the relay calibrations have not been disturbed VISUAL INSPECTION Check the nameplate stamping to make sure that the model number and rating of the relay agree with the requisition Remove the relay from its case and check that there are no broken or cracked molded parts or other signs of physical damage and that all screws are tight 10 GEK 45404 CAUTION Every circuit in the drawout case has an auxiliary brush It is especially important on current circuits and other circuits with shorting bars that the auxiliary brush be bent high enough to engage the connecting plug or test plug before the main brushes do This will prevent Current Transformer CT secondary circuits from being opened MECHANICAL INSPECTION On relays that have time dials the dials will be set at zero before the relay leaves the factory It is necessary to change this setting to open the relay contacts On all relays with locked time dials make sure the two time dial locking screws are tight These locking screws are to prevent the dial from moving when the relay is subjected to high operating torque T
14. he moving contact should be fastened securely in its support and should engage the stationary contact about in the middle or at least 1 16 inch inside the periphery of the stationary contact The stop arm leaf spring should deflect about 1 64 inch and the stop arm should clear the molded block by at least 0 020 inch Any foreign material must be cleaned out of stator air gaps Clearance between the disk and either the drag magnet or U magnet should be at least 0 010 inch for any position of the disk End play of the disk should be from 0 005 inch to 0 010 inch End play should not be so great as to allow the disk to strike the U magnet or the drag magnet Check that top and bottom pivot and bearing screws are tight There should be no noticeable friction in the rotating structure Rotate the time dial to the zero position Check by means of a neon lamp that the contacts just close there should be approximately 1 32 inch wipe on the stationary contact If the contact does not close adjust the disk position by backing off the two clamping screws on the stop arm and rotating the stop arm relative to the cutout in the disk This is coarse adjustment Retighten the clamping screws For fine adjustment of contact closing run the stationary contact brush in or out by means of its adjusting screw after this adjustment check that the screw is held firmly in its support 11 GEK 45404 ELECTRICAL TESTS Drawout Relavs General Since al
15. increase caring and deterioration of the contacts Abrasive paper or cloth may leave minute particles of insulating abrasive material in the contacts and thus prevent closing The burnishing tool described above can be obtained from the factorv SERVICING For servicing and adjustments see applicable instructions under ACCEPTANCE TESTS INSTALLATION AND MAINTENANCE RENEWAL PARTS It is recommended that sufficient quantities of renewal parts be carried in stock to enable the prompt replacement of any that are worn broken or damaged Parts bulletin number GEF 3897 gives a list of those most subject to wear in ordinary operation or to damage due to possible abnormal conditions When ordering renewal parts address the nearest Sales Office of the General Electric Company specify quantity required and give name of part wanted complete nameplate data including serial number If possible give the General Electric Company s requisition on which the relay was furnished 16 FIG 1 FIG 2 FIG 3 FIG 4 FIG 5 FIG 6 FIG 7 FIG 8 Fig 9 FIG 10 FIG 11 FIG 12 FIG 13 FIG 14 FIG 15 GEK 45404 LIST OF FIGURES 8043181 TYPE IAVSID RELAY REMOVED FROM CASE FRONT VIEW 8043182 TYPE IAVSID RELAY REMOVED FROM CASE REAR VIEW K6400439 5 INTERNAL CONNECTIONS OF THE IAVSID RELAY FRONT VIEW 0362A5 14 3 INTERNAL CONNECTIONS OF THE 5 RELAY FRONT VIEW K6556505
16. iodic checks will vary depending upon environment type of relay and the user s experience with periodic testing Until the user has accumulated enough experience to select the test interval best suited to his individual requirements it Is suggested that the points listed under INSTALLATION PROCEDURE be checked every six months Revised since last issue MAINTENANCE These relays are adjusted at the factory and it 1s advisable not to disturb the adjustments If for any reason they have been disturbed the following points should be observed in restoring them DISK AND BEARINGS The lower jewel may be tested for cracks by exploring its surface with the point of a fine needle Ifit Is necessary to replace the Jewel the new Jewel should be turned up until the disk 15 centered in the air gap after which it should be locked in position by the set screw provided for the purpose 15 GEK 45404 CONTACT CLEANING For cleaning fine silver contacts a flexible burnishing tool should be used This consists of a flexible strip of metal with an etched roughened surface resembling effect a superfine file The polishing action is so delicate that no scratches are left vet corroded material will be removed rapidly and thoroughly The flexibilitv of the tool ensures the cleaning of the actual points of contact Fine silver contacts should not be cleaned with knives files or abrasive paper or cloth Knives or files mav leave scratches which
17. l drawout relavs in service operate in their cases it Is recommended that they be tested in their cases or an equivalent steel case In this way any magnetic effects of the enclosure will be accuratelv duplicated during testing A relav mav be tested without removing it from the panel bv using a 12XLA13A test plug This plug makes connections only with the relay and does not disturb any shorting bars in the case Of course the 12XLA12A test plug may also be used Although this test plug allows greater testing flexibility it also requires CT shorting jumpers and the exercise of greater care since connections are made to both the relay and the external circuitry Power Requirements General All alternating current operated devices are affected by frequency Since non sinusoidal waveforms can be analyzed as a fundamental frequency plus harmonics of the fundamental frequency it follows that alternating current devices relays will be affected by the applied waveform Therefore in order to test alternating current relays properly it 1s essential to use a sine wave of current and or voltage purity of the sine wave i e its freedom from harmonics cannot be expressed as a finite number for any particular relay however and relay using tuned circuits RL or RC networks or saturating electromagnets such as time overcurrent relays would be especially affected by non sinusoidal waveforms Similarly relays requiring DC control power should be
18. mal calibration it is permissible to insert an inverted potential transformer between the machine neutral transformer and the relay coil circuit The IAVSID has a seal in element Time curves are shown in Fig 11 The IAV51K relay is similar to IAV51D except that it has an external capacitor Time curves shown in Fig 11 GEK 45404 IAV52K relay 15 similar to the IAVSIK except that it has two instead of one normally open contacts The IAV52C is a low pickup time overvoltage relay with two normally open contacts It has a seal in element It has a capacitor connected in series with the operating coil but unlike the IAV51D relay it does not have a tapped resistor connected in series with the operating coil The time voltage characteristics at the 1 5 and 10 time dial settings are the same as for the taps of the IAV51 52D and K relays shown in Fig 11 CONSTRUCTION These relays are the induction disk construction The disk is actuated by a potential operating coil on a laminated U magnet The disk shaft carries the moving contact which completes the trip or alarm circuit when it touches the stationary contact or contacts disk shaft is restrained by a spiral spring to give the proper contact closing voltage and its motion is retarded by permanent magnets acting on the disk to give the correct time delay There is a seal in unit mounted to the left of the shaft This unit has its coil in series and its c
19. nsformers or some automatic means must be employed to disconnect the relay from the voltage supply When this fault occurs it is equivalent to shorting out one phase of the potential transformer primary The other two unfaulted phases of the PT primaries now have full phase to phase voltage applied and their corresponding dJelta secondaries will be supplying V3 times their normal rated voltage The broken delta equivalent voltage will be these two voltages added in series at a 60 angle and the GEK 45404 broken delta voltage will therefore be three times the normal delta phase to phase voltage with no fault RATINGS The operating circuit ratings available are shown in Table I The operating coil will stand rated voltage continuously on any tap RELAX VOLTAGE RATINGS 60HZ 5OHZ IAVSID 345 345 52 345 345 x 119 2 x 6 6 2 current closing rating of the contacts is 30 amperes for voltage not exceeding 250 volts The current carrying ratings are affected by the selection of the tap on the seal in coil as indicated in Table II TABLE FUNCTION AMPERES SI 2 Amp Tap Tripping Duty Carry Continuously The 2 ampere tap has DC resistance of 0 13 ohms and 60 cycle impedance of 0 53 ohms while the 0 2 ampere tap has a 7 DC resistance and a 52 ohm 60 cycle impedance tap setting used on the seal in element 1s determined by the current drawn by the trip coil
20. nsitive overvoltage ground detection for high impedance grounded generators or for ungrounded power systems These relays all have a capacitor in series with the operating coil For the IAV5IK and IAV52K relays this capacitor 15 external to the relav because of its large size The effect of the capacitor 1s to tune the relay coil circuit so that the relay pickup on third harmonic 180Hz voltage 15 approximately eight times the relay pickup at 60 Hz This is particularly important in overvoltage ground detection for generators since they produce a large third harmonic component of voltage during normal operation The external connection diagram for the IAV51K or the IAV52K relay for sensitive generator ground detection is shown in Fig 8 This is a typical protection scheme for a unit generator transformer using a distribution transformer connected in the neutral with a resistor across the transformer secondary The IAV51K 52K relays are usually used for this application because they provide the very sensitive 5 4 volt pickup rating This enables the relay to detect a ground fault within a few percent of the winding from the neutral Since the power transformer and the station service transformer in a unit generator transformer scheme are both connected in delta on the generator side coordination with other protection is virtually unnecessary and the ground relay used can be very sensitive Some time delay in relay operation is usually used to coordinate
21. nt the right hand stationary contact from getting out of adjustment Screws should not be in both taps at the same time as pickup for DC will be the higher tap value and AC pickup will be increased Voltage Seiting The voltage at which the contacts operate may be changed by changing the tap of the IAV51D IAV52D and relays The pickup of any of the relays when set for minimum pickup can be adjusted by means of the spring adjusting ring The ring may be turned by inserting a tool in the notches around the edge By turning the ring the operating voltage of the 52 relay may be brought into agreement with the nameplate value and in the same way the IAV5ID IAVSIK and IAV52K relays may be brought into agreement with the minimum tap setting For taps other than minimum the slide band on the adjustable resistor associated with the selected tap In series with the operating coil should be moved until the pickup is at tap voltage This adjustment should not be made until the spring adjustment for minimum pickup is made since the spring adjustment sets the basic torque level of the relay Adjustments for pickup between calibrated taps can be made by selecting the tap closest to the desired voltage and then adjusting the resistor band associated with the tap selected The relay is adjusted at the factory to operate from any time dial position at a minimum voltage that is 8 of rated voltage The relays reset at 90 or more of
22. ontacts in parallel with the main contacts such that when the main contacts close the seal in unit picks up and seals in When the seal in unit picks up it raises a target into view that latches up and remains exposed until released by pressing a button beneath the lower left corner of the cover The case 16 suitable for either surface or semi flush panel mounting and an assortment of hardware 15 provided for either mounting The cover attaches to the case and also carries the reset mechanism when one is required Two of the cover screws have provision for a sealing wire The case has studs or screw connections at the bottom for the external connections The electrical connections between the relay units and the case studs are made through spring backed contact fingers mounted in stationary molded inner and outer blocks between which nests a removable connecting plug that completes the circuits The outer blocks attached to the case have the studs for the external connections and the inner blocks have the terminals for the internal connections The relav mechanism is mounted in a steel framework called the cradle and is a complete unit with all leads being terminated at the inner block This cradle is held firmly in the case by a latch at the top and the bottom and bv a guide pin at the back of the case The case and cradles are so contructed that the relav cannot be inserted in the case upside down The connecting plug besides making the elect
23. rical connections between the respective blocks of the cradle and case also locks the latch in place cover which 15 fastened to the case by thumbscrews holds the connecting plug in place To draw out the cradle from a single ended case the cover must first be removed Then the connecting plug can be drawn out In so doing the trip circuit 1s the first one opened then the voltage circuits are opened After the connecting plug has been removed the lower latch can be released and the cradle easily drawn out To replace the cradle the reverse order should be followed The internal connections of the relays are shown in Figs 3 4 5 6 and 7 GEK 45404 RECEIVING HANDLING AND STORAGE RECEIVING These relavs when not shipped as a part of a control panel will be shipped in cartons designed to protect them against damage Immediatelv upon receipt of the relav an examination should be made for any damage sustained during shipment If injury or damage resulting from rough handling 15 evident a damage claim should be filed at once with the transportation companv and the nearest General Electric Sales Office should be notified promptly HANDLING Reasonable care should be exercised unpacking the relav order that none of the parts injured nor the adjustments disturbed STORAGE If the relays are not to be installed immediately they should be stored in their original cartons in place that is free from moistur
24. tested using direct current and not full wave rectified power Unless the rectified supply is well filtered many relays will not operate properly due to the dips in the rectified power Zener diodes for example can turn off during these dips As a general rule the DC source should not contain more than 5 ripple Pickup voltage Test The pickup voltage should be checked for the IAV51D IAV51K and IAV52K the pickup voltage should be checked on more than one tap See relay nameplate for value of pickup voltage closing volts Test connections Fig 10 are the same as for the time voltage test except that the timer is not required Time voltage Test The time voltage curves should be checked for one or more settings Recommended test connections for this test are shown in Fig 10 12 GEK 45404 INSTALLATION INSPECTION At the time of installation the relav should be inspected for tarnished contacts loose screws or other imperfections If any trouble is found it should be corrected see MAINTENANCE Check the nameplate for model number and rating LOCATION The location should be clean and dry free from dust and excessive vibration and well lighted to facilitate inspection and testing MOUNTING The relav should be mounted on a vertical surface The outline and panel drilling dimensions are shown in Fig 14 for relay Types IAV51D IAV52D and IAV52C Fig 15 shows outline and panel drilling for relay Types IAVSIK and IAV
25. with fuses protecting against faults on the secondary side of potential transformers that are normally connected to the generator terminals The usual practice is to use these relays to trip the generator breaker and shut down the machine If the relay is used only to sound an alarm when a ground fault is detected the application should be reviewed It may be necessary to add another relay to provide ground protection with good sensitivity simultaneously with a high continuous voltage rating The resistor shown in Fig 8 connected across the broken delta secondary of the PT s or alternatively connected in series in the primary neutral connection is usually required to prevent the occurrence of ferro resonance This phenomenon could occur due to the interaction of the PT inductance with the distributed capacitance to ground of the primary power system The external connection diagram for the IAVSID 52D or the IAV52C relay for ground fault detection on an ungrounded power system is shown in Fig 9 The relay operates to detect the first ground fault that occurs on the system connections so that it can be removed before a second ground occurs causing a double phase to ground fault which requires a service interruption Since the relay may be applied merely to sound an alarm in this application it is necessary that it be continuously rated for the full broken delta voltage expected for a single phase to ground fault located right at the potential tra
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