HITACHI TRACTION MOTOR (HS – 15250A) OF ELECTRIC LOCOMOTIVES

PREFACE Traction motor is one of the most important equipment of electric locomotives which Provides driving power to the wheel. Its proper upkeep and maintenance is necessary to ensure good Reliability and availability of electric locomotives in service.

This handbook on maintenance of Hitachi Traction Motor type HS 15250A has been prepared By CAMTECH with the objective of making our maintenance personnel aware of correctMaintenance and overhaul techniques to be adopted in field.

It is clarified that this handbook does not supersede any existing provisions laid down by Railway Board. The handbook is for guidance only and it is not a statutory document.I am sincerely thankful to SSE and technician for his valuable comments. I am also thankful to all field personnel who helped us in preparing this handbook.

DATE DEEPESH PRATAP SINGH

16-07-2015 (GLA UNIVERSITY) BATCH- 2013-17

CONTENTSChapter No. Description Page No.

1. GENERAL DESCRIPTION 011.1 INTRODUCTION 011.2 TECHNICAL DATA 011.3 CONSTRUCTIONAL FEATURES 041.4 POWER SUPPLY ARRANGEMENTS 062. MAINTENANCE OF TRACTION MOTOR 082.1 TRIP INSPECTION 082.2 IA SCHEDULE 082.3 IB SCHEDULE 102.4 IC SCHEDULE 113. OVERHAULING 143.1 GENERAL 143.2 INCOMING INSPECTION/ TESTING 143.3 GENERAL CLEANING 153.4 DISMANTLING 163.5 CLEANING OF ARMATURE BEARING 233.6 CHECKING OF ARMATURE BEARINGS 233.7 CLEANING OF ARMATURE, STATOR AND OTHER PARTS 243.8 OVERHAULING OF ARMATURE 243.9 OVERHAULING OF ROCKER RING (BHRR & BRUSH HOLDERS) 27

3.10 OVERHAULING OF MAGNET FRAME (STATOR) 283.11 OVERHAULING OF PE & CE BRACKETS 293.12 OVERHAULING OF TERMINAL AND INSPECTION COVERS 293.13 OVERHAULING OF EARTHING PLUNGER ASSEMBLY 293.14 CHECKING OF PINION 293.15 REASSEMBLY OF ARMATURE BEARINGS 303.16 REASSEMBLY OF TRACTION MOTOR 323.17 FITTING OF CARBON BRUSHES 363.18 TEST THE MOTOR ON NO LOAD 363.19 FINAL ASSEMBLY CHECKING 363.20 INSPECTION AND TESTING PROFORMA FOR OVERHAULINGOF TRACTION MOTOR 373.21 SPECIAL TOOLS FOR TRACTION MOTOR OVERHAULING 424. COMMON FAILURES 435. DO’S AND DON’TS 465.1 DO’S 465.2 DON’TS 47CHAPTER 1GENERAL DESCRIPTION1.1 INTRODUCTION

HITACHI TRACTION MOTOR TYPE HS15250A Hitachi traction motor is one of the most critical and vital equipment in conventional Electrical locomotives type WAG-7 & WAP-4 under production at CLW.The production of Hitachi TM is now completely stabilized.

(HITACHI TM TYPE HS15250A)

Traction motor is one of the most important equipment of electric locomotives.Traction motor type HS-15250 A was specially developed by M/s Hitachi for IndianRailways. This traction motor is being used in AC locomotives type WAG-5, WAG-7,WAP-4 and AC/DC locomotives type WCAM-3.

It is a six pole dc series wound motor with commutating poles. It is of the forcedVentilation system and cooling air is supplied by the separate motor blower. It isattatched to its respective driving axle of bogie by nose suspension and tractive effort istransmitted from the traction motor to the axle through gear device with a singlereduction. In this traction motor axle taper roller suspension drive (bearing) is used inplace of sleeve bearings.1.2 TECHNICAL DATA1.2.1 Rating Continuous One hour Maximum ValuesVoltage 750V 750V 900 VCurrent 900 A 960A 1300 A

RPM 895 rpm 877 rpm 2150 rpmPower 630 KW 670 KW --1.2.2 Resistance Values At 115°C At 25°CArmature winding 0.01283 ohm ± 10% 0.00953 ohms ± 10%Series field winding 0.01184 ohms ± 10% 0.00880 ohms ± 10%Commutating pole winding 0.00907 ohms ± 10% 0.00674 ohms ± 10%1.2.3 Armature DetailsCore diameter : 500 mmCore Length : 480 mmDistance between bearing abutment faces : 949mmOverall length of armature : 1336 mm1.2.4 Armature Permanent BandingMaterial : 0.33 TK x 25 wide (Glass Binding Tape)Turns on PE winding : 70 nos.Turns on CE winding : 86 nos.1.2.5Armature bearings Pinion side Commutator sideType of bearings NU 330 NJ324 + HJ324Manufacturer NSK/ SKF/ FAG NSK/ SKF/ FAGRadial clearance of freebearing when new0.165/0.210mm 0.155/0.195mmFitment between inner raceand shaftIntf = 0.045/0.086mm Intf = 0.039/0.075mmFitment between outer raceand bearing bracketIntf = 0.046mm toClr = 0.018mmIntf = 0.041mm toClr = 0.016mmCharge of lubricant (totalvolume)925 gm. 864 gm.1.2.6 CommutatorDiameter with new : 400mmMinimum usable diameter : 380mmRiser width : 20mmMica groove depth : Max. 2.5 mmMin. 1.2mmMica groove width : 1.1 mmLength of working face : 146 mmMica thickness : 1.16 mm1.2.7 Carbon BrushesNumber per brush holder : 3Brush grade : EG 105 S (ACPL) or EG 9049 (SCI)

Brush type : 2 splitBrush size : 20mm x 40mm x 64mm splitBrush spring pressure : Max. 3.44 kg/brush ± 10% (With new brush)Min. 2.82 kg/brush ± 10% (With condemn brush)Brush wear limit : Brush length is 25 mm1.2.8 Brush HoldersNumber per motor : 6Clearance bottom of brushholder to commutator : 2~ 4mm

1.2.9 Pole Bores (average)Main pole (at centre) : 512.7 mm (Nominal air gap = 6.35mm)Commutating pole(at centre) : 520 mm (Nominal air gap = 10.0mm)1.2.10 Liner at Back PoleMain pole : NilCommutating pole : 4.9mm1.2.11 Axle Suspension TubeRoller bearing details : Gear end Non gear endManufacturer : TIMKEN TIMKENType of bearing : Taper roller Taper rollerCone M349547 Cone M249747Cup M349510 Cup M 249710Charge of lubricant (total volume) 1250gm. 900gm.1.2.12 Gear CaseInitial charge of lubricant : 8.5 litres1.2.13 LubricantArmature bearing : Shell Alvania grease no.3/Servo Gem RR3/Lithon 3Axle suspension bearing : Shell Alvania grease no.3/Servo Gem RR3/Lithon3Gear case compound : Shell Cardium Compound D or F or E/Bharat Camex Compound F/ H.P. gear tak 2.1.2.14 Weight (Approx.)Complete motor : 3485 kg(including gear case and motorsuspension unit)Armature : 1010 kgPinion : 29 kg. (for 18 teeth pinion)1.2.15 Dielectric Test VoltageNew : 5720V, A.C. for 1 min.Periodical checking : 3432 V, AC for 1 min.1.2.16 Other DetailsMinimum field strength : 40%Insulation class : Class ‘C’ (200)Gear Ratio : 18 : 64 (WAG-5), 16 : 65 (WAG-7),23 : 58 (WAP-4)Number of poles : 6Air volume : 90 m3/min.Air pressure : 150 mm (WG).

Earth return brush : Grade BM-51 (ACPL), BE-14Z1 (ELCA): Size New – 53.5mm, Condemn – 34.4mm1.3 CONSTRUCTIONAL FEATURESFollowing are the main parts of traction motor type HS-15250A.1.3.1 ArmatureIt is rotating part of the motor, consisting of a number of copper conductorssuitably placed and connected so as to form a closed winding. Armature core is built upfrom high quality electrical varnished sheet steel laminations assembled on the shaftwith interference fit and consolidated under pressure.The core and commutator are fitted directly onto the armature shaft. Thearmature is lap wound with kapton coveredconductors. The armature coil leads are TIG weldedto commutator risers in order to improve thestrength and have low voltage drop. The armaturecoils are held down in the core slots by Epoxy glasswedges and the end windings are secured by Res-Iglassbands. The wound armature is finally VacuumPressure Impregnated with solventless epoxy resininsulating varnish.

1.3.2 CommutatorThe commutator is of arch bound construction built-up with hard drawn silverbearings copper segments which are insulated with micanite segments and areassembled with moulded mica insulation between steel V-rings. After assembly, thecommutator is statically and dynamically seasoned to ensure stability. The completearmature is dynamically balanced. The commutator outer mica V-ring is protected withanti-creepage PTFE tape/ring.1.3.2.1 CommutationThe function of the commutator in d.c. motor is to reverse the direction ofcurrent in each conductor as it passes from one pole to another, it helps to develop acontinuous and unidirectional torque.The current in particular conductor is in one direction when the conductor ismoving under the North pole and in the opposite direction, when it is moving underSouth pole. This reversal of current in a coil will take place when the two commutator

segments to which the coil is connected are being short circuited by a brush. Thisprocess of reversal of current in a coil is termed as commutation. The period duringwhich coil remains short circuited is very small. If the current reversal is completed bythe end of short circuit then the cummutation is ideal. If reversal is not completed bythat time, then sparking is produced between the brush and the cummutator whichresults in progressive damage to both. The rapid reversal of current in the armature coresets up a self induced emf, generally called reactance voltage, which hinders the reversalof current and tends to delay the current reversal in the coil. As a result, the current inthe short circuit coil does not attain its full value in the reversed direction by the end ofshort circuit. This is the basic cause of sparking at commutator.

1.3.2.2 Method of improving commutationArrangement is made to neutralize the reactance voltage by producing areversing e.m.f. in the short circuited coil under commutation. This reversing e.m.f. asthe name shows, is an e.m.f. in opposition to the reactance voltage and if its value ismade equal to the reactance voltage, it will completely wipe it off, thereby producingquick reversal of current in the short circuited coil which will result in sparklesscommutation. For this purpose, special commutation poles (inter pole) are placed midway between the main poles and wound with comparatively few heavy gauge Cu wireturns and are connected in series with the armature so that they carry full armaturecurrent. Their polarity should be opposite to the next main pole in the direction ofrotation. The field produced by the interpole winding opposes the armature field.The mmf developed by the interpole must be stronger than the armature mmf inthe neutral zone, because this mmf has to cancel the armature mmf and in additioninduce an emf in short circuit coil which opposes reactance voltage and the voltage dropat the brushes.1.3.3 Stator (Magnet Frame)The high permeability cast steel or fabricated roundmagnet frame is machined to ensure alignment of the endshields, pole bores and axle way bores. Mainpole and compolecoils are edge wound, curved epoxy insulated and bonded topole bodies using epoxy resin. This improves heat dissipationand eliminates spring and support plates.

1.3.4 Rocker Assembly & Brush HoldersThis motor is 6 pole type motor and the brush holders aremounted on the rocker ring that is fixed to the bearing bracket atcommutator side by four bolts. The brush holders and carbonbrushes can be inspected by rotating the rocker ring until eachbrush holder comes to the inspection window. The brush holdersare mounted on the rocker ring by one insulating rod. Brushescan be changed without dismantling the motor. Flame retardentmodified ETFE(fluonlex) cable is used for brush gear connections.

1.3.5 Arcing HornsArcing horns are provided near the brush holders on the rocker ring to minimizethe damage in an event of a flash over.1.3.6 Armature BearingThe armature is supported on two grease lubricated cylindrical roller bearings atboth the ends. Bearing may be greased intermediately. At the commutator side type NJ324 + HJ 324 roller bearing is used and at the pinion side type NU 330 is used. Thearmature is located axially by the commutator end bearing, while the pinion end bearingis capable of taking care of any axial play between armature and frame.1.3.7 Motor Suspension UnitThe axle suspension unit is made from cast steel and at the both ends cylindricalroller bearing housings are formed. Tapered roller bearings (TIMKEN) are used at bothsides of tube. The suspension bearings are lubricated with grease. Grease is suppliedthrough a grease nipple fitted to the suspension tube by a grease pump.1.3.8 PinionThe pinion which is shrunk fitted on the armature shaft, drives the loco axlethrough a spur gearwheel which is pressed onto the axle. It is made of high-speedcarbon steel and case carburised.1.3.9 Gear CaseThe gear case is of welded steel construction and is two halves, which are boltedtogether. The complete gear case is supported on the motor frame and end shield PE.

The joints between the gear case halves are baffled and grooved to carry felt sealingrings so as to prevent ingress of dust and any other foreign material and the escape ofthe gear lubricant.1.3.10 Earth Brush and Earth Brush HolderThe earth brush holder is installed on the axle section of the magnet frame. Theearth brush is made of metallic carbon and pressed to the axle by the coil spring.1.3.11 Terminal BoxThe terminal boxes have been provided at the commutator side and pinion side.On the reverse of the terminal cover, the packing is stuck to prevent dusts from cominginto the terminal box.1.3.12 Cooling SystemThe traction motor is of the forced ventilation system and cooling air is suppliedby the separate motor blower. One motor blower supplies cooling air to the group ofthree traction motors.1.4 POWER SUPPLY ARRANGEMENTSIn traction position all the 6 traction motors M-1 to M-6 are supplied by the twosilicon rectifiers in two groups of 3 motors each connected in parallel through contactorsL-1 to L-6. The output from the rectifier assembly is taken through a smoothing reactorand is fed to the motor circuits. The direction of the rotation of the traction motor isreversed by reversing the connection to the motor field windings with the help ofreverser thus enabling the locomotive to run in either direction.Permanent field weakening resistance RPS 1-6 in parallel with the fieldwindings of motors are used to prevent the ripple component of the current from passinginto the field windings.Three step field weakening resistance are connected through contactors for eachmotor. These resistances in steps control the field of the traction motor.For electrical braking (rheostatic) the motors are disconnected from the siliconrectifiers and the armatures are connected to the braking resistances by means of thetraction braking switch CTF 1-2. The exciting winding of the traction motors areconnected in series and fed by the braking excitation transformer ATFEX and RSI-1.

CHAPTER 2MAINTENANCE OF TRACTION MOTORPeriodical maintenance is essential to ensure safety, reliability and continuous operationOf traction motors over long time periods.Following maintenance schedules are to be followed for traction motors (type HS-15250A).

Schedule Freight locomotive Pass./Mail/Exp. Train locomotiveTI 20 days Every 3000 Km. or one trip which ever is laterIA 45 days 40 daysIB 90 days 80 daysIC 135 days 120 daysWork to be carried under each maintenance schedule is given below.2.1 TRIP INSPECTIONCarry out the following inspection and fill up the proforma

Sno.

Inspection and work to be carried out Standard value

Actual value

1. Check general appearance of all traction motors fromoutside for any abnormality

No abnormality

2. Check the inspection covers for proper attachment. Ok 3. Check the cables of all traction motors visually for

anyrubbing or damages

No damage

2.2 IA SCHEDULE

Carry out the following inspections and fill up the proforma.

S. No.

Inspection & work to be carried out Standard value

Actual value

1. Clean inspection covers before removing them and checktheir condition.

Clean,ok

2. Examine the commutator thoroughly with the help of torchlight or hand lamp for a uniformly colored, well polished surface, free from bar marked, groove and high mica.

Clean, well polished

3. Remove copper beads from the commutator surface with fine cloth.

clean

4. Check commutator riser for solder run out. No damage5. Check the following through inspection window up

toPossible extent.

5.1 Check the condition of arcing horns and clearance. Ok, 11.5-13.5 mm

S. No.

Inspection & work to be carried out Standard value

Actual value

5.2 Check brush holder and positive/ negative lead insulatorsfor proper glaze and clean them.

Clean

5.3 Check the carbon brushes for chipping, mechanicaldamages and breakage of pig tails.

No damage

5.4 Check the size of carbon brushes and if required, changethe brushes which are likely to wear beyond the permissiblelimit before the next maintenance schedule.(Exchange limit 30mm)

New -64mmCondemn -25mm

5.5 Check the flexible leads are firmly secured to the brushholders.

Secure

5.6 Check the tightness of rocker lock pin and rocker holdingbolt.

Ok

5.7 Check the bellow net & bellow condition. Ok5.8 Rotate rocker if found necessary. Ok6. Examine the motor for signs of flashover,

overheating,loose connections and damaged insulation.

No abnormality

7. Check the cables of all traction motors visually for anyrubbing or damages.

No damage

8. Check the MP & IP bolts and if required, apply the ‘M’seal/RTV compound.

Ok

9. Check visually from PE endshield net for any abnormality.

No abnormality

10. Check visually earthing brush connection, terminal covers,cables cleats, both ends end shields and overall appearancefor any abnormality.

No abnormality

2.3 IB SCHEDULECarry out the following inspections and fill up the proforma

S. No.

Inspection & work to be carried out Standard value Actual value

1. Clean inspection covers before removing them and check their conditonInspection & work to be carried out

Clean,ok

2. Examine the commutator thoroughly with the help oftorchlight or hand lamp for a uniformly coloured, wellpolished surface, free from bar marked, groove and highmica.

Clean, well polished

3. Remove copper beads from the commutator surface withfine cloth.

Clean

4. Check commutator riser for solder run out. No damage5. Check the following through inspection window up to

possible extent.5.1 Check the condition of arcing horns and clearance. Ok, 11.5-13.5mm5.2 Check brush holder and positive/ negative lead

insulatorsfor proper glaze and clean them.

clean

5.3 Check the carbon brushes for chipping, mechanicaldamages and breakage of pig tails.

NO Damage

5.4 Check the size of carbon brushes and if required, changethe brushes which are likely to wear beyond the permissiblelimit before the next maintenance schedule.(Exchange limit 30mm)

New-64mmcondemn -25mm

5.5 Check the flexible leads are firmly secured to the brushholders.

secure

5.6 Check the tightness of rocker lock pin and rocker holdingbolt.

Free

5.7 Check the bellow net & bellow condition. Ok

5.8 Rotate rocker if found necessary. Ok6. Examine the motor for signs of flashover, overheating,

loose connections and damaged insulation.No abnormality

7. Check the cables of all traction motors visually for anyrubbing or damages.

No damage

8. Check the MP & IP bolts and if required, apply the ‘M seal/RTV compound.

Ok

9. Check visually from PE endshield net for any abnormality.

No abnormality

10. Check visually earthing brush connection, terminal covers,cables cleats, both ends end shields and overall appearancefor any abnormality.

No abnormality

2.4 IC SCHEDULECarry out the following inspections and fill up the proforma

S. No.

Inspection & work to be carried out Standard value Actualvalue

1. Clean inspection covers before removing them andcheck their condition.

Clean, ok

2. Blow out the interiors of the motor. Blown3. Clean commutator with fluff – free cloth, moistened

with a suitable solvent (such spirit).clean

4. Examine the commutator thoroughly with the help oftorchlight or hand lamp for a uniformly coloured, wellpolished surface, free from bar marked, groove and

high mica.

Clean, well polished

5. Remove copper beads from the commutator surfacewith fine cloth and inspect visually commutator endbanding and risers for abnormality.

Clean, no abnormality

6. Check interpole lead for any crack. Ok7. Clean hands with suitable solvents & cloth. Clean8. By Rotating the rocker ring , check the following.8.1 Measure spring tension of each spring and check their

condition and record in format ‘A’.2.82 kg. to 3.44kg. per brush

8.2 Check up spring pins by hand. Ok8.3 Check the carbon brushes for chipping, mechanical

damage and breakage of pig tails.No damage

8.4 Measure the length of each carbon brush and record informat “A”. Replace them which are likely to wearbeyond the permissible limit before the nextmaintenance schedule(Exchange limit 30mm)

New – 64 mmCondemn 25mm

8.5 Check the flexible leads are firmly secured to the brushholders.

Secure

8.6 Check each brush is free in its pocket. If it is sticking,wipe the brush with a fluff-free cloth moistened with a

suitable solvent and also clean the brush pocket

Free

8.7 Check the condition of arcing horns and measureclearance and record in format ‘A’..

Ok, 11.5 – 13.5mm

8.8 Measure the gap (clearance) between brush holderbottom and commutator and record in format ‘A’.

2-4 mm

8.9 Check brush holder and positive/ negative leadinsulators for proper glaze and clean them.

Clean

8.10

Tight the rocker lock pin and rocker holding bolt. Tighten

8.11

Check the bellow net, there should be no foreignmaterial or oil.

Ok

9. Examine the motor for signs of flashover, overheating,loose connections and damaged insulation.

No abnormality

S.No.

Inspection & work to be carried out Standard value Actualvalue

10. Lubricate inspection covers latches. Lubricate11. Check external cables of traction motors for wear and

any rubbing mark.No damage

12. Check connections of earth return brush. Ok13. Check the condition of T.M. bellows and if required,

got them replaced.Ok

14. Check the MP & IP bolts and if required, apply ‘M’seal /RTV compound.

Ok

15. Check visually from PE end shield net for anyabnormality.

No abnormality

16. Ensure availability and proper tightness of PE/CE endshields and bearing covers bolts.

Available/tighten

17. Check bearing covers of PE & CE side endshields forany looseness or hitting marks.

No abnormality

18. Replace the gaskets of inspection cover/ terminalcovers if required.

Ok/replaced

19. Check visually top & bottom lug, PE/ CE end shields,cable cleats and overall general appearance for anyabnormality.

NO abnormality

20. Clean terminal box covers, remove them and checktightness of terminal box connections.

Intact.

21. Check grease leakage from armature bearings, cleanand got attended if required.

NO leakage

22. Grease both end armature bearings with pneumaticgrease pump.

greased

CHAPTER 3OVERHAULINGOverhauling of traction motor is to be carried out during every AOH/IOH/POH.Periodicity for Overhauling

Major schedule Freight locomotives Pass./ Mail/ Exp. train locomotives

AOH 18 months 12 monthsIOH 54 months or 6 lakhs kms.

which ever is earlier36 months or 4 lakhs kms. whichever is earlier.

POH 9 years or 12 lakhs kms.which ever is earlier

6 years or 8 lakhs kms. which ever isearlier.

Details of work to be carried out during overhauling is given as under:3.1 GENERALFirst of all remove the bogie from the vehicle.Remove as much dirt as possible particularly around the inspection covers, the axlecap and the armature bearing caps on position.Remove the motor from the bogie and brought it to the TM section for overhauling.3.2 INCOMING INSPECTION/ TESTINGBring motor to the testing place.Remove terminal covers and also the dummy cover on bellow fixing location.Meggar the connection terminals of TM with 1000 v Meggar and record the IRvalues in the proforma.Carry out visual inspection for any damage/ defect/ deficiency and note the same.Note the existing modifications and modifications which are not existing, to be doneduring overhauling.Carry out run test of T.M. by connecting variable d.c. supply to its terminal(connecting armature & field in series) and the run the motor.Check bearing noise, vibration and ovality and record in the proforma.Off the switch and disconnect d.c. supply.Ensure implementation of all SMIs.

3.3 GENERAL CLEANING3.3.1 Cleaning Material3.3.1.1 ClothCloth used for cleaning of traction motor parts should be non-fluffy, clean and dry,unless it is moistened with a recommended solvent.Cotton waste or fluffy cloth should not be used for cleaning brushgear, commutatoretc. since left over flufts or fibres may cause failure.3.3.1.2 Compressed airDry compressed air should be used to blow out traction motor.3.3.1.3 Cleaning solventsWarningAs all solvents are toxic to a varying degree, the minimum amount of solvent shouldbe used and the workshop area should be well ventilated.Some solvent when heated become more toxic and therefore, the cleaning of hotsurface should be avoided.Smoking should be prohibited in all areas where solvents are used, since some arehighly inflammable.When using solvents, the operator should wear plastic gloves and not rubber sincesome solvents can be absorbed through the skin with harmful results.i. For cleaning of electrical winding parts having silicon based, class ‘H’insulation ORION 77 may be used.ii. For cleaning of mechanical parts ORION 510 diluted with kerosene oil in

the ratio of 1:6 may be used.Note: Ensure that oil based cleaning solutions used for general body cleaning arenot allowed to come in contact with windings.3.3.2 Cleaning methodsCleaning of accessible parts of traction motor should be carried out by wiping theparts with a dry cloth or, if necessary, with a cloth lightly moistened with the aboverecommended solvents.Cleaning of inaccessible parts of machines, for example, behind the field coilsshould be carried out by spraying the part with a solvent. The spray of solvent mustbe kept moving over the surface.The spray cleaning of the field system of a traction motor should not exceed 15minutes and spray rinse 3 to 5 minutes.

3.4 DISMANTLING3.4.1 GeneralBring the motor from testing place to dismantling place.Disassembly of the traction motor must be performed at a clean place with no dust,and the parts must be handled carefully not to damage and rust.Observe the orders of disassembly correctly.The conditions on the work (for instance, temperature, pressure, amount of greasesupplied etc.) must be observed strictly.

3.4.2 Flow Chart for Dismantling

3.4.3 Disassembly of Pinion From Armature ShaftLoosen the pinion-locking nut so that clearance of 3 to 4mm is made between thenut and pinion.Remove the pinion by oil injection method as described below.1. By oil injection methodA groove is machined around the armature shaft extension on the pinionseating and is connected by vertical drilled hole to a tapped hole parallel in theend face of the shaft. This is provided for the removal of the pinion by oilinjection, oil under high pressure being supplied by a oil injector pump

The tapped hole in the shaft is sealed with a rubber screwed plug toprevent gear lubricant from entering and blocking the oil ways. Follow theprocedure mentioned below:Remove all traces of gear lubricant from the pinion, the shaft end and theoil injection plug using a solvent, such as white spirit.Remove the plug which seals the oil injection hole, using the plug driver/screw driver.Remove gear lubricant if found its way past the plug.Assemble the oil pump and injector attachment, fit the high-pressure pipeand fill the pump reservoir.

Do not fit the pump handle at this stage.Open the pump relief valve using the fingers.Operate the pump until air bubbles cease to the expelled with the oil.Close the relief valve again.Operate the pump handle socket with the fingers until system is full of oiland resistance of pumping is felt.Fit the pump handle and continue pumping raising the pressure graduallyand pausing after each stroke to let the pressure built up at the pinionseating.A sudden loss of pressure accompanied by movement of the pinion indicates its release.

2. Method for removal of pinion when extraction fails due to leakage of oilIn some cases, difficulties may be faced in removing the traction motorpinion from shaft due to leakage of oil during extraction of pinion by oilinjection method. In such type of case, follow the methods, mentioned belowrespectively.Material and equipment requiredi. ‘M’ seal putty : For sealing the oil leakage.ii. Hot oil : For heating the pinion.iii. Oil injection equipmentiv. Hydraulic Ram

Procedure - IBy applying ‘M’ seal putty1. Clean the face of the pinion & shaft with petrol or suitable cleaning solvent.2. Wipe and clean the pinion faces & shaft with dry cloth.3. Apply thick layer of ‘M’ seal putty on both side faces of the pinion at the matingpoints of pinion bore periphery and shaft, to seal the same.

4. Allow the putty to cure at room temperature for 12 hours.5. After the putty gets cured, heat the pinion slightly with the gas torch.6. Extract the pinion with oil injection method which is explained earlier.7. If oil still leaks out through ‘M’ seal putty, repeat the process as per clauses 1 to6.Procedure – IIBy heating the pinion :1. Clean the faces of the pinion & shaft with petrol or suitable cleaning solbent.2. Apply Hydraulic Ram for pulling out the pinion.3. While applying extraction force, pour hot oil (200 deg. C approx.), over thepinion.4. If the pinion is not getting extracted, apply oil pressure simultaneously by usingoil injection. For this purpose, a small metallic spacer may be used in betweenshaft end and ram of the puller so as to enable fitting of oil injection plug intothe shaft.NOTEi. The procedure II of pulling and heating the pinion to be used only after oilinjection with ‘M’ seal fails repeatedly.ii. The use of excessive pressures may cause the pinion to be ejected violently, itmay then rebound and reseat itself on the shaft.iii. Excessive pressures may also cause permanent distortion of the pinion bore.iv. Refit the plug in the oil injection hole immediately after removal of the pinion toprevent the ingress of foreign material.v. Protect the pinion bore and shaft extension from damage and corrosion.

3.4.4 Disassembly of Outer Bearing Stopper (pinion side)Dismount the outer bearing stopper (pinion side) by using the exclusive tools asshown in fig. 3.2

Item No. Description Tool mark Qty.1. Nut TL-4 12. Double end stud TL-5 63. Support disk TL-6 14. Nut M16 -- 65. Ram with oil power pump -- 13.4.5 Disassembly of Armature3.4.5.1 PreparationThe armature is to be dismounted from the stator with the bearing bracket (endshield) at the pinion side kept fitted. Before dismounting the armature, make preparationas follows:Remove all the carbon brushes from the brush holders by disconnecting terminalbolts of carbon brushes lead wires and rotating rocker ring.After removing the carbon brushes, wind a press board on the commutator forpreventing the commutator surface from being scratched.Dismount the bearing cover from the bearing bracket (CE end shield) utilizing thetapped hole for pulling out.Dismount the outer bearing stopper (CE) and thrust collar of roller bearing (CE)from the armature shaft.3.4.5.2 DisassemblyAfter completion of the preparation for disassembling thearmature, keep the motor upright with the commutator sidedownside.

Remove all bolts tightening the bearing bracket (PE end shield),screw M24 bolts into three tapped holes in the bearing bracket(PE end shield) and dismount the bearing bracket (PE endshield).

Fit the armature lifting hook on the armature shaft end at thepinion side, lift the armature by crane, screw the bolts in thetapped holes of bearing bracket (PE end shield) in turn, turn thearmature slowly till the spigot joint of bearing bracket (PE endshield) and magnet frame comes off, and while checking to seethat the armature is turned smoothly, dismount the armature andbearing bracket (PE end shield) together from the stator.

Place the armature dismounted from the stator on a woodentable with laid down, supported by the core face.Never support the armature with the coil, glass bind part or commutator part.

3.4.6 Disassembly of Bearing Bracket (PE end shield)For disassembling the bearing bracket (PE end shield), insert a steel bar

(20 to 24 mm india.) into the bearing bracket bolt hole andextract the bearing bracket crosswise with itlifted and supported by crane.Extract the bearing bracket in arrow markdirection.Write serial number with white paint to PEend shield and armature.

3.4.7 Disassembly of Commutator Side Bearing Bracket (end shield)Dismount the CE bearing bracket (end shield) from the magnet frame utilizing thetapped hole for pulling out.As the outer ring of roller bearing will come out together with the bearing frame,pay full attention when handling the bearing bracket. Write the serial number withwhite paint to CE end shield.3.4.8 Disassembly of Rocker RingRemove one special reamer bolt (dowel bolt) that is fixing the rocker ring to themagnet frame commutator side. (This work is already performed during removal ofcarbon brushes for rotating the rocker ring).Remove the rocker from the magnet frame and write serial number with white paintto rocker ring and magnet frame.3.4.9 Disassembly of Armature Bearings3.4.9.1 Disassembly of roller bearing inner ring at pinion sideWhen the bearing bracket (end shield) at the pinion side is removed from thearmature, the following parts are fitted on the armature shaft pinion side:Inner bearing stopper, bearing inner ring and outer bearing stopper.After dismounting the outer bearing stopper, dismount the inner bearing stopper andbearing inner ring simultaneously by using the exclusive tools as shown in the fig.

3.5.

Item no. Description Tool mark Qty.1. Hook TL-12 2(1set)2. Keeper plate TL-3 13. Nut TL-4 14. Double end stud TL-14 45. Support disk TL-6 16. Nut M24 -- 47. Ram with oil power pump -- 18. Bolt M24 L-40 -- 23.4.9.2 Disassembly of bearing inner ring at commutator sideWhen the bearing bracket at the commutator side is removed from the magnetframe, the bearing inner ring and inner bearing stopper are fitted on the armature shaftcommutator side. Dismount these parts at the same time by using the exclusive tools

shown in the fig. 3.6.

Item no. Description Tool mark Qty.1. Hook TL-12 2(1set)2. Keeper plate TL-3 13. Nut TL-4 14. Double end stud TL-14 45. Support disk TL-6 16. Nut M24 -- 47. Ram with oil power pump -- 18. Bolt M24 L-40 -- 2

3.5 CLEANING OF ARMATURE BEARINGSTo clean the dismounted armature bearings,put them into a vessel containing kerosene heated upto about 60C withoutdegreasing and leave them as they are in kerosene for more than 10 minutes. Afterthat wash them roughly and take them out of the vessel. Then blow away stickinggrease with compressed air.Repeat the procedures more than twice, and then, wash the bearings finally withclean kerosene having ordinary temperature and blow away adhering kerosenecompletely with air.For the final washing, always use new kerosene and do not use heavily oxidised orfoul one.Wash hands with a degreasing agent such as ethyl alcohol/ petrol carefully forpreventing the bearings from getting rusty when handling after the final wash.3.6 CHECKING OF ARMATURE BEARINGSCheck visually for roughness, scratch, bruise, discoloration, rust etc. on inner &outer race too.Check while moving the rollers for wear of retainer, looseness of rivets and makesure that there is no abnormality.If any abnormality observed in either inner or outer ring, replace with new set ofbearings.Check radial clearance of bearings of PE & CE side before assembling and record.

Check ID of bearings of PE & CE side before assembling and record.Check for inner & outer ring of same serial number and same serial number ringsshould be assembled.Note : Whenever a new bearing is provided, the date of commissioning of bearingshould be engraved on the bearing.

3.7 CLEANING OF ARMATURE, STATOR AND OTHER PARTSClean the armature thoroughly by clean and dry compressed air.Metallic portion of armature shaft to be cleaned with white spirit or ORION 510diluted with kerosene in the ratio of 1:6 by spray gun.After the cleaning the solvent should be wiped off with clean cloth.Stator (magnet frame) should also be cleaned thoroughly by clean dry compressedair.Cleaning of spaces between & behind the field coils is to be done when magnetframe (stator) stood on end, so that dirt to drop out freely.Clean both end shields.Clean moving deflector, pinion, locking nut of pinion.Clean locking plates, bolts, terminal box cleats, inspection covers etc.3.8 OVERHAULING OF ARMATURECheck visually for any damage, both side resiglass bond, pinion seat for anyabnormality.Check IR value by 1 kV meggar between commutator and body.Check the condition of pinion seat on shaft.Measure the commutator dia (new- 400 mm. & condemning dia 380 mm.).Measure the following dimensions and record:i) Diameter of bearing seat on PE & CE side.ii) Deflector seat dia. & deflector bore dia.3.8.1 Ultrasonic Testing of Armature ShaftUltrasonic testing of armature shaft is to be carried out to detect any flaw etc. toavoid the failures of armature shaft.This is to be carried out as per RDSO SMI No. RDSO/ELRS/SMI/150 dt. 23.11.92.3.8.2 Maintenance of Commutator SurfaceThe necessity of reworking the commutator surface is determined depending onits condition and the judgement. It must be judged observing the condition ofcommutator surface carefully and can be maintained as following.3.8.2.1 GrindstoneApplying “Grindstone” must rework the commutator exhibiting the followingconditions:Where the commutator surface is heavily blackened.Where the commutator surface is rough owing tominor flashover.Procedure:Put the armature on a lathe and applygrindstone. After completion of applying agrindstone, blow away the stone powder with air andcheck carefully the groove inside, between commutator bars to be sure that there is noabnormality.

3.8.2.2 Turning of Commutator surfaceIn case where the following conditions are recognised, apply turning to thecommutator surface:If eccentricity, unequally in diameter, high-bar, low-bar etc are generated incommutator, cut the commutator as per given table.Item Corrective Limits After TurningEccentricity Not more than 0.1mm 0.03 mmInequality in diameter Not more than 0.06 mm 0.006mmHigh, low-bar Not more than 0.05 mm 0 mm

In case that stepped wear is caused in commutator surface:The stepped part should be corrected flat by turning. Standard for turning –when `w’ (depth of stepped portion) exceeds 0.1mm at the maximum, it requirescutting work.In case where it is impossible to rework by a grindstone because the commutatorsurface is heavily rough.The degree of turning of commutator surface should be judged according to theconditions of commuter surface, and it must be cut at minimum required limit.3.8.2.3 Turning Procedure (Resurfacing)When correcting the commutator surface by the lathe, align the armature shaft asshown below in figure 3.10

Push the shaft end of armature shaft on the commutator side by the centre oflathe, align the armature shaft by using the bearing fitting portion A, on the pinion sideas reference and chuck the shaft end on the pinion side. Apply a steady rest to thebearing-fitting portion B, on the commutator side.Resurfacing of commutator to be done as per RDSO SMI No.RDSO/ELRS/SMI/6 and SMI/29.3.8.2.4 Mica under Cutting and ChamferingWhen the commutator surface is cut, the slot between the commutator barsshallows and chamfering of commutator bars, become too small. Therefore aftercutting, under cutting, chamfering should be performed with suitable tool. This is to bedone as per RDSO SMI No. 31. Details of under cutting & chamfering are shownbelow in figures 3.11 to 3.14.

3.8.2.5 CleaningOn the completion of cutting the commutator surface, clean by blowing airdirectly to it. To protect the commutator surface from injuring, a press board andpolyester tape should be winded.3.8.3 Creepage Area SurfaceThe creepage area surface, should be kept in good condition. The area shouldbe cleaned and painted with anti track varnish or E 233 varnish. The procedure forpainting this surface is as follows:Clean surfaces thoroughly with alcohol/petrol. Remove any trace of carbon.Using a clean brush, apply the insulation paint carefully to the creep age surface.Make a coat as thin as possible applying the insulation varnish evenly leaving nodabs or overlapping areas.Take care to avoid getting varnish into commutator slots or the relief at the bottomcommutator neck.3.8.4 Varnishing of ArmatureBake the armature for 2 hours at 80 deg. C and varnishing to be done with anti-trackvarnish or E 233 varnish and again bake for 2 hours at 80 deg C.Check again IR value by 1 kV meggar between commutator and body. It should beminimum 10 M ohms.3.8.5 Cleaning of the Surface of Glass TapeClean the surface of glass bind and the side of commutator bars by wiping withclean cloth containing petrol.Check the condition of resiglass binding.After keeping the armature at room temperature for 2 hours or longer, dry itscleaned surface with portable dryer.3.8.6 Cleaning of Surfaces of Commutator and Teflon RingRemove the protection cover from commutator surface.Check whether varnish, finishing varnish or any other article does not remain ingrooves, and if you find them, you should clear them away.Clean Teflon ring and if the Teflon ring is found loose, distorted or damaged,replace with new one.3.8.7 Bar to Bar Conductor Resistance & Equiliser Resistance TestsOne of the most important “condition monitoring” tests, is the bar to bar resistancecheck on traction motor. This is very important test to detect defective joints incommutator risers, open or short circuited coils. This test should be done with aprecision digital resistance meter with least count of a few micro ohms.This test is to be carried out as per instructions given in SMI no.

RDSO/ELRS/SMI/51 dt. 30.04.1979.3.8.8 Millivolt Drop TestThis test is carried out for detecting cross connection of leads, short circuits or opencircuits in the armature winding coils and behind the commutator riser.This test is to be carried out as per instructions given in the RDSO SMI no.ELRS/SMI/25 dt. 24.07.78.3.8.9 Tan-Delta MeasurementThe measurement of tan-delta (dissipation factor) is carried out for checkinginsulation between armature shaft and winding. The measurements should be carriedout between the commutator (with all segments shorted by a copper wire) and thearmature shaft.For carrying out this test refer SMI no. RDSO/ELRS/SMI/128 dt. 19.06.1985.This should be recorded in armature history card.3.8.10 Surge Comparison TestCarry out surge comparison test and record in the proforma.3.8.11 Balancing : If required, balancing of armature to be done.3.9 OVERHAULING OF ROCKER RING (BHRR) & BRUSH HOLDERSRemove and clean all 06 nos. brush holders.Repair & clean flash marks on brush holders.Check the spring tension, if required adjust.Make sure that the carbon brush moves smoothly into the pocket of brush holder.Check the condition of arcing horns, if found flashed/ damaged, repair/replace thesame.Check the condition of threads of pig tail fixing holes on brush pocket and tap it ifrequired.Apply bectol red varnish on pocket from outside area.Clean rocker ring (BHRR).Check the condition of Teflon sleeve of insulating rod assembly, if requiredreplace it.Check the tightness of all 06 nos. insulating rod assemblies.Check the tightness of positive and negative insulating rod and also check theirstud threads, if found damage/slack, replace the insulating rod.Check the condition of lead wire for flash/ insulation damage, if required replace/repair.Check the binding of lead wire with ‘C’ clamp, if found loose/damage, rebind it.Check IR of each insulator and lead wire by 1 kV meggar, if IR found less, replacethe insulator.Fit the overhauled brush holders on rocker ring and connect the lead wires.Carry out HV testing on 3 KV for one minute and measure the leakage current andrecord.3.10 OVERHAULING OF MAGNET FRAME (STATOR)Ensure proper cleaning of magnet frame from outside and inside.Check distance between motor lugs, if required replace wearing plates.Check the condition of gear case mounting lug, bushes if found worn out/ablongreplace it.Bake the frame for 5 hours at 100 deg.C and varnishing to be done with anti-track

varnish or E 233 red varnish by spraying and again bake the frame for 3 hours at100 deg.C.Check IR value by 1 kV meggar and record.Check the resistance of MP & IP coils and record in the proforma.Check the Tan- Delta of MP, IP & record.Check the pole bore dia at main pole and commutating pole at centre.Check the distance of magnet frame between connecting faces of axle suspensiontube as per SMI-207.Perform H.V. test by applying 2.5 kv a.c. supply for one minute and measure theleakage current of the stator and record.Check the condition of lead wire terminal for ovalness and crackness.Check nose suspension lug by D.P. test.Check top lug thickness and record.Measure distance between lug mounting bush and stator collar and record.Check the PE & CE side housing end shield bore dia and record.Check the brazing joints of field coils (MP) by injecting high current and ensurethe temperature rise at joints by hands. This is to be carried out as per RDSO SMIno. RDSO/ELRS/SMI/ 151 dtd. 08.12.92 and also record the voltage drop.Check the insulation of positive & negative lead.Remove drain plug and refit after cleaning and tapping.Check locking arrangement of inspection cover on body and repair if required.Provide locktite on MP, IP fixing bolts after checking tightness of bolts withtorque wrench as per RDSO mod. WAM4/165.Provide RTV to MP fixing bolts-03 nos. and terminal insulators-04 nos. at motorsuspension unit tube portion.Check IR value of terminal insulators by 1 kV meggar and record.Clean the wooden cleat and varnish them.3.11 OVERHAULING OF PE & CE BRACKETS (END SHIELDS)Clean the PE & CE end bracketsCheck the wire mesh, if found broken/ damage, repair/ replace it.Apply anti-track varnish or E 233 red varnish on both end brackets from inside.3.12 OVERHAULING OF TERMINAL & INSPECTION COVERSClean terminal box covers and inspection covers.Remove old gasket from covers.Repair the covers where found bend/cracks.Provide new gaskets to covers.Paint the covers.3.13 OVERHAULING OF EARTHING PLUNGER ASSEMBLYDismantle the earthing plunger.Clean all parts.Check the condition of earthing brush, if found condemn in size, replace it.Check the spring for its proper tension.Repair the body of earthing plunger, if found damage.Assemble all parts.3.14 CHECKING OF PINIONClean the pinion with kerosene, XYLOL or similar solvent with a brush and wipe

with a cloth.Examine the pinion visually for any damage, discoloration, excessive wear or anyother defect.Pinion should be checked with red dye penetrating test (RDPT) for any crackness onits teeth/body.Measure dimension ‘k’ over the specified teeth as per proforma and note the averagevalue of 8 different measurements by a micrometer of suitable size. It should bewithin specified limit. If ‘k’ value is found less than specified value then scrap thepinion and fit new pinion.Check the “p” value of pinion teeth, it should be less than 0.4mm.3.15 REASSEMBLY OF ARMATURE BEARINGS3.15.1 PreparationReassemble the armature bearings carefully after cleaning and be careful withingress of dust, etc. during reassembling process.When reassembling the bearings do not strike or pressure fit them unduly.Shell Alvania grease no.3/Servogem RR-3/ Lithon-3 grease to be used and nevermix with grease of other brands.Fill grease in the bearing bracket and bearing cover at the PE & CE side as shown infig.3.15 (PE side 925 gm. and CE side 864 gm.)

3.15.2 Reassembly of Roller Bearing Inner Ring at Pinion SideWipe carefully the bearing inner ring assembling part of the armature shaft and fitthe inner bearing stopper and inner ring in place in following order:Put the inner bearing stopper and bearing inner ring into the oil bath containingkerosene heated up to 110 to 120°C for heating them and shrink fit on the armatureshaft.When shrink fitting them on the armature shaft, press them by hand till they cool sothat gap is not produced at the stopped part of inner bearing stopper and shaft &between inner bearing stopper and bearing inner ring as shown in fig. 3.16

Shrink fit outer bearing stopper too by the same procedures.NOTE : However, outer bearing stopper must be fitted to after assembly ofarmature,After each part has been fitted on the shaft, apply grease thinly to the surface for rustprevention purpose.3.15.3 Reassembly of Roller Bearing Outer Ring at Pinion SidePressure fit the outer ring to the bearing bracket by using the exclusive tools asshown in fig. 3.17.Never fit the outer ring while striking by hammer with out using the exclusive tool;otherwise the bearing may damage

Item No.

Description Tool mark Qty.

1. Nut TL-4 42. Hook TL-11 53. Support disk TL-64. Stand TL-19 1

5. Ram with oil power pump -- 13.15.4 Reassembly of Roller Bearing Inner Ring at Commutator SideWipe carefully the bearing inner ring assembly part of the armature shaft and put theinner bearing stopper and bearing inner ring in position in following order:Put the inner ring and inner bearing stopper into the bath containing kerosene heatedup to 110 to 120°C for heating them and shrink fit on the armature shaft.When shrink fitting them onto thearmature shaft, press them by handtill they cool so that gap is notproduced at the stepped part ofinner bearing stopper and inner ringas shown in fig. 3.18.

3.16 REASSEMBLY OF TRACTION MOTORReassembly can be made easily by reversing the procedure of disassembly. Priorto reassembly, prepare all parts and tools necessary for reassembly correctly.3.16.1 Preparation for ReassemblyBefore reassembling clean all parts by blowing air.Use all the lock washers new.Pre-fit armature bearings to the armature shaft, bearing bracket and bearing framewith the inner race, bearing stopper and outer race.Wind a press board on the surface of commutator for protection of the surface andmake preparation for reassembly.3.16.2 Tightening Torque of Each Bolt and NutCheck each bolt and nut for looseness and retighten as required. Each bolt andnut should be tightened with tightening torque as shown in table below.

Nominal size volt and nut Tightening torque (in .kgf. cm)Min. value Standard value Max. value

M6 41.0 51.1 61.6

M8 97.4 122.0 146.0

M10 196.0 245.0 295.0M12 355.0 418.0 503.0M16 815.0 1020.0 1225.0M20 1600.0 2000.0 2420.0M24 2800.0 3500.0 4200.0M30 5500.0 6900.0 8300.0M36 9600.0 12100.0 14500.0

Note : The desirable tightening torque is as follows:1. Stainless steel bolts : Minimum value should be applied.2. Steel bolts : Maximum value should be applied.3.16.3 Consumable Material List for OverhaulingS.No. Description Qty. Remarks1 Lock washer 1 Pinion2 Lock washer 1 Outer bearing stopper3 Gasket 2 Net of air inlet4 Gasket 1 Inspection cover of magnet frame5 Gasket 1 Cover of magnet frame6 Rubber plug 1 Armature shaft 7 Roller bearing 1 Commutator side(if required) 8 Roller bearing 1 Pinion side(if required)9 Carbon brush 1810 Earth brush 1 Earth brush assembly 11 Brush holder As required Replace if required 12 Earth brush holder 1 set Earth brush (if required)13 Grease - Servogem RR-3/ Lithon-3/ Shell

Alvania grease no.3

3.16.5 Installation of Brush Holders & Reassembly of Rocker RingReassemble the brush holders and insulating rods on rocker ring.The neutral point mark and serial number are carved on rocker ring and magnetframe. When installing the rocker ring to the magnet frame, combine ones that havethe same number.3.16.6 Reassembly of commutator side bearing bracketMount the CE bearing bracket to the commutator side of magnet frame.3.16.7 Reassembly of Pinion Side Bearing BracketMount the bearing cover to the bearing bracket and tighten the bearing cover by theboltsInsert a round steel bar to the bolt hole of bearing bracket, lift the bearing bracket bya crane and mount it to the pinion side of armature shaft as shown in fig.3.20

3.16.8 Reassembly of ArmatureKeep the magnet frame up right. Don’t tilt it. If the magnet frame is left tilted, wheninserting the armature into the magnet frame, the commutator and/or armature coilmay contact the brush holder, main pole coil, interpole coil etc. and may damagethem.Insert the armature into magnet frame kept upright, with the armature lifting hookinstalled on the shaft end at pinion side and the armature lifted by crane turning thecommutator side downward.When inserting the armature, screw guide bolts into bearing bracket clamping builtholes in the magnet frame as the guide for the bearing bracket.Lower gently the armature keeping lifted by crane. Do not lower suddenly and insertthe armature assembly unduly; otherwise bruise is caused in the bearing inner raceface.When the bearing bracket has been fitted to the due part of magnet frame, removethe guide bolt and clamp the bearing bracket with the boltsTighten the bearing bracket bolts while confirming that there is no abnormality,turning the armature. So long as the armature is assembled correctly, it can be turnedsmoothly, but if it fails to turn smoothly, re-tighten the bearing clamping boltsuniformly.

3.16.9 Reassembly of Bearing Stopper at Commutator SideAfter the armature has been assembled in place, lay the motor, install thethrust ring for cylindrical roller bearing of roller bearing inner race at the commutatorside and bearing stopper, tighten the bolt M16L35 and bend the lock washer forfixing.3.16.10 Reassembly of Commutator Side Bearing Cover and Pinion Side Outer BearingStopperMount the bearing cover to the CE bearing bracket and tighten the bearing coverby the bolts.Mount the outer bearing stopper on the pinion side by shrinkage fit (heatingtemperature 110 – 120°C).3.16.11 Shrink Fitting the PinionWash and clean the pinion with kerosene toremove the grease and oils. Then apply athin coating of red paint (Fe2O3 powder) onthe bore surface of the pinion, puttingtogether the tally mark on the shaft andpinion, force fit the pinion lightly on theshaft. Then measure the dimension `lo’ withdepth micrometer and record `lo’ as shownin figure 3.23

Remove the pinion and check the bedding between the pinion and the shaft. It isnecessary that more than 90% of entire contact area to be actually in contact. Ifthere is insufficient contact, repair the bore surface of the pinion.Heat the pinion for about one hour in an oven/ induction heater/ oil bath heated toa temperature rise of 140 10C. above room temperature. It is most important tokeep the temperature of oven/ induction heater/ oil bath accurate.Remove the pinion from oven/ induction heater/ oil bath and remove oil frompinion surface by air blowing as fast as possible (if immersed in oil bath heater).Perform shrink fitting of pinion immediately by putting together the tally markson the armature shaft and the pinion. Tighten the pinion nut lightly and allow tocool naturally.After the pinion has cooled off completely, release the pinion nut. Measure andrecord “l” dimension which is depth of shaft with respect to pinion outer surface.Make sure that the allowance between the pinion and the armature shaft end is asfollows :I0 - l = entering allowance of pinion (advancement)= 1.92 to 2.00 mm.where l0 = dimension before shrink fittingl = dimension after shrink fittingAfter making sure that the pinion entering allowance is satisfactory, insert the lockplate and tighten the pinion nut.If the pinion entering allowance is not sufficient, remove the pinion and performshrink fitting again. This must be done until perfect result have been achieved.3.17 FITTING OF CARBON BRUSHESAdjust the clearance between commutator & brush holder. It must be 2 to 4 mm(standard: 3mm)Check the gap between brush holder and riser. (4mm minimum)Before fitting, bedding of new carbon brushes is to be done.Fit the new (bedded) carbon brushes of same recommended make & grade in brushholders.Check the free movement of carbon brushes in their pocket.Tight the rocker lock pin and rocker holding bolt.

3.18 TEST THE MOTOR ON NO LOADPlace the TM at light run testing panel.Make the supply connection (armature and field connections in series) and ON thevariable d.c. supply.Increase voltage gradually till the TM gains the speed 895 rpm, allow it to run andcheck for any abnormality such as abnormal noise from bearings, vibration etc.Run the motor at 895 rpm for two hours (in both directions) and record thetemperature of bearings, the steady state temperature rise should not exceed 35 to 45deg. C above ambient.3.19 FINAL ASSEMBLY CHECKINGCheck ovality of commutator in assembled traction motor. (0.04 mm max.)Check the insulation resistance with 1 kv meggar between:i) Main pole circuit and earth.ii) Inter pole circuit and earth.iii) Main pole and inter pole circuit.It should be 10 Mohm min.Fit the P.G. clamps , terminal box covers and cleats. Also fit all inspection covers,grease nipples.Provide dummy cover on bellow portion.Provide earthing plunger assembly.Paint the motor from outside by grey paint.3.20 INSPECTION AND TESTING PROFORMA FOR OVERHAULING HITACHITRACTION MOTOR TYPE HS – 15250A

A- Stage : Pre-inspectionS. No.

Inspection/ Test Standard value Actual value

1. Check insulation resistance with 1 kVmegger between –a) Main pole circuit to earthb) Inter pole circuit to earthc) Main pole to inter pole

1 M Ohm. (min.)1 M Ohm. (min.)1 M Ohm. (min.)

2. Light run the TM by applying reduced D.C.voltage and check the following –a. Bearing noise i)P.E. side(by SPM) ii) C.E. sideb. Vibrationc. Ovality of the armature

0 – 35 dBN0-35 dBNno vibration0.05 mm (Max.)

3. Check distance between outer surface ofpinion & shaft face.

Recorded

B - Stage : Overhauling of Magnetic Frame (Stator)S. No.

Inspection/ Test Standard value Actual value

1 Do the baking before and after Done

Inspection/ Testvarnishing of stator with anti-track varnish or E 233 redvarnisha) Pre-heating for 5 hours at 100 deg. Cb) Baking for 3 hours at 100 deg. C

2 Check insulation resistance with 1kV meggarbetweena) Main pole circuit to earthb) Inter pole circuit to earthc) Main lead circuit to earthd) Main pole to inter pole

1 M Ohm. (min.)1 M Ohm. (min.)1 M Ohm. (min.)1 M Ohm. (min.)

3 Check the resistance of series field winding( at 25 deg. C temp.)

0.0079 – 0.0097Ohm

4 Check the resistance of commutating polewinding ( at 25 deg. C temp.)

0.0061 – 0.0074Ohm

5 Check the tan delta of MP, IP Recorded

6 Check the pole bore diaa. Main pole (at centre)b. Comm.. pole (at centre .

512.5 – 512.9 mm519.8 – 520.2 mm

7 Distance of Magnet frame between connectingfaces of axle suspension tube as per SMI-207

282.00 –282.052 mm

8 Perform H.V. test by applying 2.5 KV A.C.supply for one minute and measure the leakage

current of the stator.

20 mAmp. Max

9 Check top lug thickness 38-40 mm

10 Distance between lug mounting bush and statorcollar.

16.5-18 mm

Inspection/ Test11 Check the PE & CE housing e/

shield bore dia(PE)(CE

696 + 0.080 mm+ 0.00710 + 0.080 mm+ 0.00

12 Do high current injection test at 500 amp. for 20minutes & record the following –i) Temp. of joints MPii) Voltage drop MP

.

Recorded4.28-2.68 V

13 Check the distance between motor lugs 304.15-305.75 mm

14 Check the condition of liners New/serviceable

15 Check condition of gear case mounting lug bush.(Bush of 9 mm)

New/serviceable

16 Check the condition of all (04 nos.) niddle rollerbearing.

New/serviceable

17 Provision of locktite on MP, IP fixing bolts &tightening with torque wrench as per RDSO Mod.WAM4/165.

Done

18 Provision of RTV to MP fixing bolt 3 nos. &terminal insulator 4 nos. at MSU tube portion.

Done

19 Check IR value of terminal insulators by 1kVmeggar.

100 M(min.)

C. Stage : Overhauling of brush holder/rocker ring.S. No.

Inspection/ Test Standard value Actual value

1 Check spring pressure (at assly.) at brush height 64 mm (full length)

3.10 to 3.78 kgfmax.

2 i. Check brush grade/make.ii. Record length of carbon brush (new)iii. Check Clearance between bottom of brush holder to commutator.iv. Check gap between BH & riser.

EG 105S/EG 904964 mm2-4 mm4 mm (min.)

3 Insulation resistance with 1 kV meggar between the leads & rocker ring body.

10 Mega ohms(Minimum)

.

4 . Perform H.V. test on rocker ring by applying3 KV A.C. supply for one minute andmeasure the leakage current.

10 milli amps(maximum)

5 Check the arcing pointer gap 11.5 – 13.5 mm

D- Stage : Overhauling of Armature & Commutator S. No.

Inspection/ Test Standard value Actual value

1 Insulation resistance with 1 kV megger between commutator & body/shaft.(before overhauling)

To be recorded

2 Measure the commutator dia.(new commutator dia. = 400 mm)

380 mm (min. usable diameter)

3 Mica groove depth 1.2 mm(min.)2.5 mm (max.)

4 Mica groove width 1.1 mm5 Do the baking before and after varnishing of

armature with anti-track varnish or E 233 red varnish for 2 hrs. at 80 deg. C.

Done

6 Insulation resistance with 1 kV megger between commutator and body (after varnishing, baking & cooling)

10 meag ohms(minimum)

7 Check tan delta at 1 KVand at 3 KV

Less than 4%Less than 6%

8 Carry out surge comparison test 200 V between successive bar-bar

9 Conduct millivolt drop/ resistance test oncommutator as per SMI- 25 & 51 & SD to be calculated

+/-3 SD

10 Shafti. Diameter of bearing seat on pinion side.ii. Diameter of bearing seat on commutator side.iii. Check for scratch mark pitting/dent mark.

150 + 0.068 mm+ 0.043 mm120 + 0.059 mm+ 0.037 mmperfectly polished.

11 Measure the deflector seat dia. 140 + 0.117 mm+0.092

12 Measure the deflector bore dia 140 + 0.04 mm+ 0.00

13 Check UST of shaft for no flaw. Ok14 Charge of lubricant (Total volume)

i. Pinion end.ii. Commutator end

925 gms.860 gms.

15 Condition of bearing –Check for pitting mark, dents, burning ordiscolouration

No suchsymptomsGood

16 i) Radial clearance of free bearing when new.Pinion endCommutator endii) Actual radial clearance after assly.Pinion end

0.165 – 0.210 mm0.155 – 0.195 mm0.104 –0.177

Commutator endiii) PE side 1) Bearing ID:2) Bearing seat shaft dia3) Interferenceiv) CE side 1) Bearing ID2) Bearing seat shaft dia3) Interferencev) Check housing dia. of bearing. PE side(if new bearing provided)CE side

mm0.066 – 0.147 mm150+ 0/-0.009 mm150 + 0.068 mm+ 0.043 mm0.046 to 0.059 mm120 +0/-0.009 mm120 + 0.059 mm+ 0.037 mm0.041 to 0.050 mm320 – 0.010 mm– 0.046 mm260 – 0.009 mm– 0.041 mm

E- Stage : Pinion Inspection and fittingS. No.

Inspection/ Test Standard value Actual value

1 Check for any breakage of tooth and chipping & scoring mark on bore

No. breakage

2 Check for discolouration. Normal colour.3 DPT/Zyglo test of pinion. No cracks4 Check for bedding 90-100%

5 Distance between pinion outer surface & shaft face (cold condition)

Recorded

6 Distance between pinion outer surface & shaft face (hot condition)

Recorded

7 Check advancement of pinion 1.92-2.00 mm8 Check the ‘k’ value of pinion between

3 teeth for 18 teeth pinion3 teeth for 16 teeth pinion4 teeth for 23 teeth pinion

93.293–94.741mm95.88– 96.019mm131.461–131.607 mm

9 Check the ‘p’ value of pinion teeth. 0.4 mm (Max.)

F Stage : Final AssemblyS. No.

Inspection/ Test Standard value Actual value

1 Check ovality of commutator in assembled TM.

0.04 mm (max.)

2 Check the insulation resistance with 1 KVmegger between –a) Main pole circuit and earthb) Inter pole circuit and earthc) Main pole and Inter pole

10 mega ohms(Minimum)

3 Run the Traction Motor at 895 RPM on no loadfor two hours (in both direction) & check thefollowinga) Vibrationb) Bearing Noise i) PE sideii) CE sidec) Temp. rise of bearing i) PE sideii) CE sided) SPM reading to be recordedi) PE side(0-35 dBN for oldbearing)ii) CE side(0-35 dBN for oldbearing)

No VibrationNormal NoiseNormal Noise35-40 Deg. C(above ambient)10 – 20 dBN(Green Zone)(New Bearing)10-20 dBN(Green Zone)(New bearing)

CHAPTER 4DO’S AND DON’TS4.1 DO’S1. Add a few drops of mineral oil to the solvent while cleaning the bearings and

their components to protect them from rust.2. Always use torque wrench for tightening nuts & bolts as recommended tighteningtorque value.3. Always ensure that the modification/ special maintenance instructions are beingfollowed.4. Ensure that the new carbon brushes are of the same grade, as the old ones, whilereplacing the carbon brushes.5. Ensure that the cables are secured properly and not rubbing with any metal parts.6. Ensure that the washers and locking plates are properly provided whileassembling the traction motor parts.7. Ensure that the oven/ induction heater/ oil bath heater is working at therecommended temperature.8. Always use Shock Pulse Meter (SPM) for monitoring the condition of bearingsand keep a record of the bearings.9. Ensure that the all specified clearances are maintained properly.10. Ensure that the carbon brushes are removed before application of solvent forcleaning the traction motor.11. Always slip a thin clean pressboard between brush holder and the commutatorwhile replacing a brush holder to prevent damage to the commutator surface.12. Always check the clearance between the under side of the brush holder and thecommutator when refitting a brush holder.

13. Ensure that the lubricating oil/ compound of approved make are in use4.2 DON’TS1. Don’t use cotton waste or fluffy cloth for cleaning brush gear, commutator sinceleft over fluffs or fibres may cause electrical or mechanical failures.2. Don’t reuse used grease or lubricant oil.3. Don’t carry any alteration or modification without the approval of componentauthority.4. Don’t over tight cable cleats because cable insulation may damage.5. Don’t use carbon brushes of different grades on same traction motor.6. Don’t use higher voltage meggar than specified.7. Don’t use detergent or any other volatile cleaning solvent/ agent, for cleaninginside the traction motor, junction box, insulator etc.8. Don’t mix up the greases of same grade but different make.9. Don’t compromise with clearances of bearings.10. Don’t carry out the commutator resurfacing/ turning unless grooves or steppedwear or ovality is found.11. Don’t allow the wearing of carbon brushes beyond specified condemning size.12. Don’t soak the carbon brush in solvent as solvent will gradually ooze out,effecting the commutation and will cause the brush to jam in the pocket.13. Don’t run motor at high speed under no load condition for long period becauseof the possibility of rollers skid, which can cause scuffing of the track and rollersurface and premature bearing failure.14. Don’t forget to refit the plug into the oil injection hole immediately afterremoval of the pinion to prevent the ingress of foreign matter.15. Don’t strike the commutator surface, the commutator sleeve and riser. (High bar

or low-bar of the commutator may be caused).16. Don’t strike the glass bind with a hammer or polish with a file. In case that thearmature is set, it shall be supported by the armature core and never with thecommutator or glass bind.17. Don’t remove the film on the commutator surface, unless there is special reasonsuch as bad commutation, abnormal wear of carbon brush and so on. (Filmadjustment may get disarranged).18. Don’t polish the commutator surface with sand paper or a file.19. Don’t apply stone to the commutator during high speed operation or in vibration.(Bias wear or deformation of the commutator may be caused).20. Don’t release the brush spring of brush holder from hand suddenly. (The brushmay be broken or hands injured).

CHAPTER 5 COMMON FAILURES

S. No.

Failures Possible cause Suggested Remedies

1.CommuatorFlashed/poorcommutation

i. Carbon brushes of different grades & size.

Replace with the same grade and size.

ii. Sticking of carbon brushes in brush pocket

Clean the brush pocket and remove the dust etc.

iii. Chattering/vibration of Carbon brushes.

Check the spring tension & correct it.

iv. Unbalace of brush current i.e colour change in pig tail of brush.

Clean the commutator surface and polish it epoxy paper belt.

v. carbon brush slack in its housing.

Check the clearance between new carbon brush and its housing.it should be less than 0.3mm. if it is more.replace the brush holder.

vi. Defect in commutator i.e. ovality. High/low bar. Burrs.unequal oxygenated film etc.

Check the commutator surface and if required. Replace the traction motor. Commutator defect to be removed.

vii. Vibration in traction motor

Examine lateral (diametrical) clearance of axle bearing. Vibration of motor and unbalance of armature. Abnormality shall be adjusted according to the maintenance data.

2. Cricuit breaker tripping due to earth fault in Traction Motor

i. Armature insulation level less or IR value zero.

. Improve IR of armature and if required,replace the traction motor, check thearmature for earth fault and rectify thesame & TM O/H to be done.

ii. Field coil insulation damaged or IR value less/ zero.

Improve the IR value of field ciecuitand if required, replace the tractionmotor, check the field coils and rectifythe defect & TM O/H to be done

iii. IP coil insulation damaged or IR value less/zero.

Improve the IR value of interpolecircuit and if required, replace thetraction motor and attend the IP coil & TM O/H to be done.

iv. Carbon brush holder spring broken & carbon brush hanging &touching the metallic surface of TM

Replace the concerned brush holder &clean the commutator flashed area.

v. Carbon brush pig tail broken & flashed.

Check the carbon brush grade &replace with correct grade & cleanthe flashed area.

vi. Traction motor inter connection leads insulation damageed.

Rectify the defect and if required,replace the traction motor.

vii. Traction motor power cable insulation damaged due to rubbing withmetallic body.

Check and attend the damaged cableand secure all the cable properlyproviding the proper rubber gaskets.

viii. Traction motor IR less due to moisture & dust.

Clean the concerned traction motor& blow it with dry compressed airand improve its IR value, if require,replace the traction motor.

ix. Traction motor cable connection flashed in terminal box due to loose connection etc.

Check the terminal box and attendthe same. Tightness of cableconnections to be checked.

x. Insulation of brush holder insulator damaged.

Check and apply insulating varnishor replace the brush holder insulatorif required.

3. Overload relaytripping due tomore currentdrawn bytraction motor.

i) Armature winding shortcircuited or commutatorsegments shorted.

Replace the defective traction motorand rectify the defect.

ii) Motor suspension unittaper roller bearingdefective/jam causingtraction motor rotatingjam.

Replace the concerned tractionmotor. Check the taper roller bearingand attend.

iii) Traction motor armaturebearings seizure.

Replace the traction motor. Checkthe armature bearing clearances,grease condition and roller conditionetc. and replace the bearing set.

iv) Axle box bearing seizureor bearing damaged.

Check the axle box bearing andgrease condition for metal contacts &replace the axle box if required.

4.Abnormalnoise comingfrom tractionmotor.

i) Pinion teeth broken ordamaged.

Replace the traction motor and checkthe pinion fitting & pinion teeth, ifrequired, pinion to be replaced.Proper procedure to be followed forremoving & fitting of the pinion.

ii) Any foreign material inthe traction motor.

Replace the traction motor andremove the foreign material andcheck the health of traction motorand attend the defect.

iii) Armature bearingclearances more ordamaged.

Replace the traction motor andoverhaul. Check all the bearingscarefully and replace with new one ifrequired.

5.Traction noteffective i.e.particularwheel notrotating.

i) Armature winding coilor field coil or IP coilopen circuited.

Replace the traction motor and checkthe defect and attend the same.

ii) Stator MP & IPconnection lead brokenflashed or burnt.

Check the motor and attend thedefect, if required, traction motor tobe replaced.

iii) Traction motor cableconnection flashed &parted in terminal box.

Check and attend the defect onposition, replace the cable lugs etc.,if required.

6.Armature shaftbroken

Armature shaft maybroken/sheared off due toexistence of any flawpreviously.

Ultrasonic testing of armature shaftto be carried out during everyoverhauling to prevent such type offailure.

CONCLUSIONTo upgrade maintenance technologies and methodologies and achieve improvement in productivity, performance of all Railway assets and manpower which inter-alia would cover reliability, availability, utilisation and efficiency.

NAME-DEEPESH PRATAP SINGH B.Tech 3rd year

(GLA UNIVERSITY) MATHURA