OVERLOAD RELAYS, STARTERS TESTING, …

1 OVERLOAD RELAYS, STARTERSTESTING, installation & trouble & SUREL&T SWITCHGEAR30 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALOVERLOAD TEST1m1mDUT1m1mFROM CURRENT SOURCE'NC' CONTACTOF RELAYC onnections of Thermal OVERLOAD Relay for O/L TestingTESTING OF THERMAL OVERLOAD up the following data of relay under ) Relay Type _____ b) Relay Range _____c) Max. Back up fuse rating continuity of auxiliary contacts and main ) Normally open _____b) Normally closed _____c) R Pole _____d) Y Pole _____NOTE : If the answer is to all above points then only take the relay for OVERLOAD the proper size of cable for connection. In case of smaller size of cable or improper termination, relay may trip all three poles of relay in series as shown in the following proper size of cables. Length of cable should be one normally closed (NC) contact of relay in series with test panel's auxiliary contact. (This will give relay trip to test panel.)31 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUAL8.

2 Switch on the supply and adjust the test current. Immediately switch off the current. Keep variac at adjusted position. Reset the time counter. Cool the relay for about 10 Switch on the test current and check trip time of the each test, cool the relay for minimum 10 minutes. Otherwise, relay will trip early and you will not get correct Set the relay and calculate the test current as follows:Relay Setting XMultiples of Set CurrentTest Current(% of OVERLOAD )=AmpsEg.: 10 (200%)=20 Amps1. X 2(200%)=2. X 3(300%)=Sr. Current (Amp) Trip Time in Secondsi-t /Not per Curve7. Find out the minimum and maximum trip time with respect to multiples of set current you have selected and note down the values in the following size with respect to test Current AmpFor Copper Cablessq. mm 0 to 15115 to to 46446 to 66666 to 11010100 to 15025150 to 2203532 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALSINGLE PHASING TEST1m1m1mDUTFROM CURRENT SOURCE'NC' CONTACTOF RELAYCONNECTIONS OF THERMAL OVERLOAD RELAYFOR SINGLE PHASE TESTINGSr.

3 No. Relay SettingTest Current (Amp)Trip Time inSec. fromi-t /Not & SUREL&T SWITCHGEARESPSERVICEMANUALNOTE : 1. THE TRIPPING TIME FOR ANY CURRENT SHALL LIE BETWEEN THE VALUESCORRESPONDING TO 90% AND 110% OF THAT CURVE REPRESENTS COLD STATE TIME IN 7 8 MULTIPLES OF SET CURRENTTRIPPING CURVE FOR MK1 / ML1 RELAYSFOR RANGES UPTO 6-10 & SUREL&T SWITCHGEARESPSERVICEMANUALNOTE : 1. THE TRIPPING TIME FOR ANY CURRENT SHALL LIE BETWEEN THE VALUESCORRESPONDING TO 90% AND 110% OF THAT CURVE REPRESENTS COLD STATE TIME IN 1 7 8 MULTIPLES OF SET CURRENTTRIPPING CURVE FOR MK1 / ML1 RELAYSFOR RANGES UPTO 9-14 & 10-16 & SUREL&T SWITCHGEARESPSERVICEMANUAL72006000400020 001000600400200100605040302010642 TRIPPING TIME IN 5 67 8 MULTIPLES OF SET CURRENTNOTE :CURVE REPRESENTS COLD STATE TRIPTIME CURVEMINI. TRIPTIME CURVETRIPPING CURVE FOR ML2 / ML3 RELAYS36 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALTRIPPING CURVE FOR MN RELAYSON 3 POLE LOADING (BALANCED) CONDITION1000040002000100040020010040201 02 TRIPPING TIME IN SECONDSMULTIPLES OF SET 1 5 67 8 9 10115 TRIPTIME CURVE48 TRIPTIME CURVENOTE :CURVE REPRESENTS COLD STATE & SUREL&T SWITCHGEARESPSERVICEMANUALTRIPPING CURVE FOR MN RELAYSON 2 POLE LOADING (SINGLE PHASING) CONDITION1000040002000100040020010040201 0642 TRIPPING TIME IN SECONDSMULTIPLES OF SET 1 5 67 8 9 1060 :CURVE REPRESENTS COLD STATE & SUREL&T SWITCHGEARESPSERVICEMANUALMULTIPLES OF SET CURRENTTRIPPING TIME IN 10410310210110 MAX.

4 SETTINGMIN. SETTINGTRIPPING CURVE FOR MN12 L RELAYSON 3 POLE BALANCED LOADING CONDITION39 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DETAILSMN45, MN65 DOLMN25, MN32 DOLMN16 DOL40 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DETAILSMN25, MN32 SASDMN25, MN32 FASDMN16 SASDMN16 FASD41 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DETAILSMN80, MN110, MN140 FASDMN45, MN65 FASD42 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DOLML1 SASD43 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DETAILSML3 SASDML3 FASDML2 SASDML2 FASD44 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DETAILSML4, ML6 FASDML10, ML12 FASD45 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DETAILSMF1 DOL (3 PHASE) STARTERSFOR SINGLE PHASE LOADSMF1 DOL (3 PHASE) STARTERSMF1 DOL (SINGLE PHASE) STARTERS46 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALWIRING DETAILSMK1 FASDMK1 DOLMK1 SASD47 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALSTAR DELTA STARTERS (ML SERIES)Details of Contactors and timers used in ML series star delta startersStartersContactorsTimersSTARDELT AHOLD ONML 1ML ML 1ML 2 SASDML 2ML 2ML 2 ML 2 FASDML 2ML 2ML 2GT-200ML 3 SASDML 2ML 3ML 3 ML 3 FASDML 2ML 3ML 3ET-100ML 4 FASDML 3ML 4ML 4ET-100ML 6 FASDML 4ML 6ML 6ET-100ML 10 FASDML 10ML 10ML 10ET-100ML 12 FASDML 12ML 12ML 12ET-20048 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALCHART FOR DOL MOTOR STARTERSWITH ML RELAYSM otor Rating240V-1 Rating215V-3 PhaseRelayRangeContactorBack (A)InkWhpIn49 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALCHART FOR DOL MOTOR STARTERSWITH ML RELAYSM otor Rating240V-1 Rating215V-3 PhaseRelayRangeContactorBack upfuseSDFkWhpTypeRating(A) :(1)The full load currents given apply in the case of single phase motors, to capacitor-start type motors and in the case of 3 phase motors, to squirrel cage type induction motors at full load having average power factor and efficiency.

5 The motors should have speeds not less than the following:Upto 10 hp - 750 , 10 to 30 HP - 600 , 30 - 125 HP - 500 , 125 - 300 HP - 375 (2)Contactors/Switches indicated are the minimum ratings suitable for the application. Higher sizes/Ratings can be used.(3)Normal motor starting times are assumed in all & SUREL&T SWITCHGEARESPSERVICEMANUALCHART FOR STAR-DELTA MOTOR STARTERSWITH ML RELAYSNOTES:(1)Contactors/Switches indicated are the minimum ratings suitable for the application. Higher sizes/Ratings can be used.(2)For applications above 35 hp suitable scheme to be employed to ensure change over delay of 40-75ms between star and delta contactors.(3)Normal motor starting times are assumed in all 415 V (A)RelayRangeContactorNominal Backup fuse linkSDFkWhpType/SizeRatingA(A)STARPHASEL INELINEDELTA51 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALCHART FOR MF1 THREE PHASE / SINGLE PHASEM otor rating in hpRelayscaleMaximum safe rating of back-up fuses*240 VSingle phase415V3 phaseAmps(A)CartridgefusesRewritablefuse s * Cartridge type fuses are recommended52 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALCHART FOR Mk1 DOL rating Fuse RatingMaximumMinimumDiazedSWGD iazedSWGCat :Amp.

6 Rating of back-up fuse refers to the recommended diazed type HRC catridge fuse. Where rewirable semi-enclosed, tinned copper wire fuses are used, SWG number in table is approximate guide to size of wire & SUREL&T SWITCHGEARESPSERVICEMANUALCHART FOR MK1 STAR-DELTA STARTERNote:Amp. Rating of back-up fuse refers to the recommended diazed type HRC catridge fuse. Where rewirable semi-enclosed, tinned copper wire fuses and used, SWG number in table is approximate guide to size of wire No SS 96254 & SS 96257 - FASD StartersCat. No SS 96255 & SS 96258 - SASD Fuse RatingMaximumMinimumDiazedSWGD iazedSWGCat loadlinecurrentin & SUREL&T SWITCHGEARESPSERVICEMANUALSELECTION CHART FOR MU/MBDOL 6315112114-23HF63FN 63MN2MU215112120-33HF63FN 63MU2MU215112120-32HF63FN 63 MaximumMotor rating ph 50 loadCurrent inRelayRange(A)RelayContactorBack-upHRC FuseSwitchDisconectorFuse UnitHPKWTypeRating(A) 63 MaximumMotor rating ph 50 loadCurrent inRelayRange(A)Relay ContactorBack-upHRC FuseSwitchDisconectorFuse UnitHPKWTypeRating(A)PhaseCurrentSELECTI ON CHART FOR MU/MB STAR DELTA STARTERS55 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALSELECTION CHART FOR MUG-10 DOLSUBMERSIBLE PUMP STARTERSHPKWTypeRating(A)TypeTypeMaximum submersiblepump ratingat 415 V,3ph.

7 , 50hzTypeRelayRange(A)RelayContactorBack- up HRC FuseSwitchDisco-nnectorFuse 1MU 1HF16FN 1MU 1HF16FN 32 MUG-10 2MU 1HF32FN 2MU 1HF40FN 2MU 1HF16FN 32 MUG-10N 2MU 1HF32FN 2MU 2HF63FN 63 MUG-10H DOL* 2MU 2HN/0063FN 100 Note : MU 1/2 contactors are available in 415 V coil operating voltage : MUG-10 DOL are available with dry run facility as a optional feature.* - Controllers for low voltage application56 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALSELECTION CHART FOR MUG-20 STAR - DELTASUBMERSIBLE PUMP STARTERS15119-14MU 2MU 1HF32FN 32 MUG-20 Star-Delta201513-21MU 2MU 1HF40FN 63201520-32MU 2MU 2HF63FN 63 MUG-20H*Star-Delta201528-42MU 2MU 2HN/0063FN 100 Maximumsubmersiblepump ratingat 415 V,3ph., 50hzTypeRelayRange(A)RelayContactorBack- up HRC FuseHPKWTypeRating(A)TypeTypeSwitchDisco -nnectorFuse UnitNote : MU 1/2 contactors are available in 415 V coil operating voltage : MUG-10 DOL are available with dry run facility as a optional feature.* - Controllers for low voltage application57 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALC able connections to the terminalsWhen aluminium wires are used, the following method should be adopted:2If the wire is small up to 1 mm Single strand1.

8 Clean the wire surface by rubbing with a small hard wire Tin the wire immediately (within 2 or 3 minutes).3. Put wire under terminal clamp and tighten screws. Do not tighten to such an extent that the wire becomes two or three months, it may be necessary to ensure that the screws are tight and the wire has not become loose. This may happen because aluminium is soft and is likely to flow . Always apply inhibiting grease around the terminal and wire to prevent moisture from reaching the area of contact. Apply inhibiting grease, only on the terminals and wire and not on the the wire is large larger than 10 mm Multi-strandWires should be connected with the help of cable lugs or thimbles. The cable lugs may be of "soldering" or "crimping" "soldering" type cable lugs: Check that cable lug socket is clean and dry inside. Clean every strand of aluminium wire with a small hard wire brush by opening out the cable strands. Immediately dip all the strands in tin solder.

9 Insert the stranded cable in the proper size cable lug and pour solder through the cable lug. Ensure that solder fills the entire space inside the cable lug socket. Wipe off excess solder on cable insulation. Connect the cable lug to the terminal and tighten terminal screws using spring washers on the cable lug. There should not be excess load on the cable lug, or else the solder will become loose. Care must, therefore, be taken to cut the cable core and strip the insulation to the correct length. The cable lug should sit flat on the terminal and the cable should not have sharp two or three months it is necessary to check whether the connection is firm and to tighten the screws, if necessary. Also check and ensure that the cable is not loose in the cable FOR installation AND PREVENTIVE MAINTENANCE58 SAFE & SUREL&T SWITCHGEARESPSERVICEMANUALFor "crimping" type cable-lugs : Check that cable lug socket is clean and dry inside. Clean every strand of aluminium wire with a small hard wire brush after opening strands.

10 Close the strand again immediately, insert to the proper length inside the cable lug socket and crimp, using the correct crimping tool. Connect the cable lugs to the terminal and tighten terminal screws using spring washers on the cable maintenanceContact tips are made of silver compositions like silver nickel and silver cadmium oxide. In normal use, these tips may show slight brown or black tarnish. If the atmosphere around the starter contains high moisture and sulphur, the contacttips will show excessive tarnishing. To clean the contact tips, use this maintenance procedure:1. Rub the contact tips lightly with fine emery NOT FILE THE Remove small particles by rubbing with wet cotton wool or with awet, clean Remove the water on the contact tip surface with a dry, clean cloth. If possible, apply acetone or carbon terachloride. Do not use maintenance procedure is necessary only if contact tips are covered' with thick, black tarnish film. If the contact tip is uneven, but not heavily tarnished, do not disturb the replacementContact replacement becomes necessary if less than one- third of the original contact tip remains on the contact.