railways fo|qr yksdkseksfvo fo|qr yksdkseksfvo dh ddhh dh fgvkph vªsd’ku eksvj...

¦ÉÉ®úiÉ ºÉ®úEòÉ®ú ¦ÉÉ®úiÉ ºÉ®úEòÉ®ú ¦ÉÉ®úiÉ ºÉ®úEòÉ®ú ¦ÉÉ®úiÉ ºÉ®úEòÉ®ú GOVERNMENT OF INDIA

®äú±É ¨ÉÆjÉÉ±ÉªÉ ®äú±É ¨ÉÆjÉÉ±ÉªÉ ®äú±É ¨ÉÆjÉÉ±ÉªÉ ®äú±É ¨ÉÆjÉÉ±ÉªÉ MINISTRY OF RAILWAYS

fo|qr yksdkseksfVo fo|qr yksdkseksfVo fo|qr yksdkseksfVo fo|qr yksdkseksfVo dh dh dh dh

fgVkph VªSD’ku eksVj ¼,p,l & 15250,½ fgVkph VªSD’ku eksVj ¼,p,l & 15250,½ fgVkph VªSD’ku eksVj ¼,p,l & 15250,½ fgVkph VªSD’ku eksVj ¼,p,l & 15250,½ ds ds ds ds

vuqjk.k dh gLriqfLrdkvuqjk.k dh gLriqfLrdkvuqjk.k dh gLriqfLrdkvuqjk.k dh gLriqfLrdk

MAINTENANCE HANDBOOK

ON

HITACHI TRACTION MOTOR (HS – 15250A)

OF

ELECTRIC LOCOMOTIVES

TARGET GROUP – TECHNICIANS AND SUPERVISORS OF ELECTRIC LOCO SHEDS/ WORKSHOPS

Centre for Advanced Maintenance TECHnology

Excellence in Maintenance

¨É½þÉ®ú¨É½þÉ®ú¨É½þÉ®ú¨É½þÉ®úÉVÉÉÖ®úÉVÉÉÖ®úÉVÉÉÖ®úÉVÉÉÖ®ú, M´ÉÉÊ±ÉªÉ®ú M´ÉÉÊ±ÉªÉ®ú M´ÉÉÊ±ÉªÉ®ú M´ÉÉÊ±ÉªÉ®ú ---- 474 020474 020474 020474 020

Maharajpur, GWALIOR - 474 020

dseVsd@bZ@2005@Vh,e¼,p½@1-0 CAMTECH/E/2005/TM(H)/1.0

tuojh 2005

January, 2005

fo|qr yksdkseksfVo fo|qr yksdkseksfVo fo|qr yksdkseksfVo fo|qr yksdkseksfVo dh dh dh dh

fgVkph VªSD’ku eksVj ¼,p ,l & 15250,½ fgVkph VªSD’ku eksVj ¼,p ,l & 15250,½ fgVkph VªSD’ku eksVj ¼,p ,l & 15250,½ fgVkph VªSD’ku eksVj ¼,p ,l & 15250,½ ds ds ds ds

vuqjk.k dh gLriqfLrdkvuqjk.k dh gLriqfLrdkvuqjk.k dh gLriqfLrdkvuqjk.k dh gLriqfLrdk

MAINTENANCE HANDBOOK

ON

HITACHI TRACTION MOTOR (HS – 15250A)

OF

ELECTRIC LOCOMOTIVES

TARGET GROUP – TECHNICIANS AND SUPERVIS ORS OF ELECTRIC LOCO SHEDS/ WORKSHOPS

FOREWORD

With increasing freight and passenger traffic, reliability and availability of electric locomotives have become very important. Proper maintenance of traction motor is vital to ensure good reliability and availability of electric locomotives in service.

CAMTECH has prepared this handbook to cover all essential aspects of maintenance and overhauling of Hitachi Traction Motor type HS 15250A. It describes various maintenance schedules, overhauling procedure and trouble shooting for common failures.

I am sure the book will prove to be very useful for our maintenance staff in electric loco sheds

and workshops.

CAMTECH, Gwalior R.N.Misra Date :20th January, 2005 Executive Director

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 correct maintenance and overhaul techniques to be adopted in field.

It is clarified that this handbook does not supersede any existing provisions laid down by RDSO or Railway Board. The handbook is for guidance only and it is not a statutory document.

I am sincerely thankful to Director, Std./ Elect./ RDSO/ LKO for his valuable comments. I am also thankful to all field personnel who helped us in preparing this handbook.

Technological upgradation and learning is a continuous process. Hence feel free to write us for any addition/modification in this handbook. We shall highly appreciate your contribution in this direction.

CAMTECH, Gwalior Randhawa Suhag Date :20th January, 2005 Director Electrical

Chapter No. Description Page No.

Foreword iv Preface vi Contents viii Correction Slip ` xii

1. GENERAL DESCRIPTION 01 1.1 INTRODUCTION 01

1.2 TECHNICAL DATA 01

1.3 CONSTRUCTIONAL FEATURES 04

1.4 POWER SUPPLY ARRANGEMENTS 06 2. MAINTENANCE OF TRACTION MOTOR 08

2.1 TRIP INSPECTION 08

2.2 IA SCHEDULE 08

2.3 IB SCHEDULE 10

2.4 IC SCHEDULE 11 3. OVERHAULING 14

3.1 GENERAL 14

3.2 INCOMING INSPECTION/ TESTING 14

3.3 GENERAL CLEANING 15

3.4 DISMANTLING 16

3.5 CLEANING OF ARMATURE BEARING 23

3.6 CHECKING OF ARMATURE BEARINGS 23

3.7 CLEANING OF ARMATURE, STATOR AND OTHER PARTS 24

3.8 OVERHAULING OF ARMATURE 24

3.9 OVERHAULING OF ROCKER RING (BHRR & BRUSH HOLDERS) 27

3.10 OVERHAULING OF MAGNET FRAME (STATOR) 28

3.11 OVERHAULING OF PE & CE BRACKETS 29

3.12 OVERHAULING OF TERMINAL AND INSPECTION COVERS 29

3.13 OVERHAULING OF EARTHING PLUNGER ASSEMBLY 29

3.14 CHECKING OF PINION 29

3.15 REASSEMBLY OF ARMATURE BEARINGS 30

3.16 REASSEMBLY OF TRACTION MOTOR 32

3.17 FITTING OF CARBON BRUSHES 36

3.18 TEST THE MOTOR ON NO LOAD 36

3.19 FINAL ASSEMBLY CHECKING 36

3.20 INSPECTION AND TESTING PROFORMA FOR OVERHAULING

OF TRACTION MOTOR 37

3.21 SPECIAL TOOLS FOR TRACTION MOTOR OVERHAULING 42

CONTENTS

Chapter No. Description Page No. 4. COMMON FAILURES 43 5. DO’S AND DON’TS 46

5.1 DO’S 46

5.2 DON’TS 47 ANNEXURE ‘A’ – SPECIAL MAINTENANCE INSTRUCTIONS 48 ANNEXURE ‘B’ – MODIFICATION SHEETS 49 REFERENCES 50

ISSUE OF CORRECTION SLIPS

The correction slips to be issued in future for this handbook will be numbered as follows : CAMTECH/2004/E/TM(H)/C.S. # XX date--------- Where “XX” is the serial number of the concerned correction slip (starting from 01 onwards). CORRECTION SLIPS ISSUED

Sr. No. Date of issue Page no. and Item no. modified

Remarks

CAMTECH/E/2005/TM(H)/1.0

Maintenance Handbook on Hitachi Traction Motor(HS-15250A) of Electric Locomotives January, 2005

1

CHAPTER 1

GENERAL DESCRIPTION 1.1 INTRODUCTION

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 Indian Railways. 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 forced ventilation system and cooling air is supplied by the separate motor blower. It is attatched to its respective driving axle of bogie by nose suspension and tractive effort is transmitted from the traction motor to the axle through gear device with a single reduction. In this traction motor axle taper roller suspension drive (bearing) is used in place of sleeve bearings.

1.2 TECHNICAL DATA

1.2.1 Rating Continuous One hour Maximum Values Voltage 750V 750V 900 V Current 900 A 960A 1300 A RPM 895 rpm 877 rpm 2150 rpm Power 630 KW 670 KW --

1.2.2 Resistance Values At 115°C At 25°C Armature 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 Details

Core diameter : 500 mm Core Length : 480 mm Distance between bearing abutment faces : 949mm Overall length of armature : 1336 mm

Figure 1.1 Traction Motor HS – 15250A



2

1.2.4 Armature Permanent Banding

Material : 0.33 TK x 25 wide (Glass Binding Tape)

Turns on PE winding : 70 nos.

Turns on CE winding : 86 nos. 1.2.5

Armature bearings Pinion side Commutator side

Type of bearings NU 330 NJ324 + HJ324

Manufacturer NSK/ SKF/ FAG NSK/ SKF/ FAG

Radial clearance of free bearing when new

0.165/0.210mm 0.155/0.195mm

Fitment between inner race and shaft

Intf = 0.045/0.086mm Intf = 0.039/0.075mm

Fitment between outer race and bearing bracket

Intf = 0.046mm to Clr = 0.018mm

Intf = 0.041mm to Clr = 0.016mm

Charge of lubricant (total volume)

925 gm. 864 gm.

1.2.6 Commutator

Diameter with new : 400mm

Minimum usable diameter : 380mm

Riser width : 20mm

Mica groove depth : Max. 2.5 mm Min. 1.2mm

Mica groove width : 1.1 mm

Length of working face : 146 mm Mica thickness : 1.16 mm

1.2.7 Carbon Brushes Number per brush holder : 3

Brush grade : EG 105 S (ACPL) or EG 9049 (SCI)

Brush type : 2 split

Brush size : 20mm x 40mm x 64mm split

Brush 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 mm 1.2.8 Brush Holders

Number per motor : 6

Clearance bottom of brush

holder to commutator : 2~ 4mm



3

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 Pole

Main pole : Nil Commutating pole : 4.9mm

1.2.11 Axle Suspension Tube

Roller bearing details : Gear end Non gear end

Manufacturer : TIMKEN TIMKEN

Type of bearing : Taper roller Taper roller Cone M349547 Cone M249747

Cup M349510 Cup M 249710

Charge of lubricant (total volume) 1250gm. 900gm.

1.2.12 Gear Case

Initial charge of lubricant : 8.5 litres

1.2.13 Lubricant

Armature bearing : Shell Alvania grease no.3/Servo Gem RR3/Lithon 3

Axle suspension bearing : Shell Alvania grease no.3/Servo Gem RR3/Lithon3

Gear 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 motor suspension unit)

Armature : 1010 kg

Pinion : 29 kg. (for 18 teeth pinion)

1.2.15 Dielectric Test Voltage

New : 5720V, A.C. for 1 min.

Periodical checking : 3432 V, AC for 1 min.

1.2.16 Other Details Minimum 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 : 6 Air volume : 90 m3/min. Air pressure : 150 mm (WG).

Earth return brush : Grade BM-51 (ACPL), BE-14Z1 (ELCA) : Size New – 53.5mm, Condemn – 34.4mm



4

1.3 CONSTRUCTIONAL FEATURES Following are the main parts of traction motor type HS-15250A.

1.3.1 Armature

It is rotating part of the motor, consisting of a number of copper conductors suitably placed and connected so as to form a closed winding. Armature core is built up from high quality electrical varnished sheet steel laminations assembled on the shaft with interference fit and consolidated under pressure.

The core and commutator are fitted directly onto the armature shaft. The

armature is lap wound with kapton covered conductors. The armature coil leads are TIG welded to commutator risers in order to improve the strength and have low voltage drop. The armature coils are held down in the core slots by Epoxy glass wedges and the end windings are secured by Res-I-glass bands. The wound armature is finally Vacuum Pressure Impregnated with solventless epoxy resin insulating varnish.

1.3.2 Commutator

The commutator is of arch bound construction built-up with hard drawn silver bearings copper segments which are insulated with micanite segments and are assembled with moulded mica insulation between steel V-rings. After assembly, the commutator is statically and dynamically seasoned to ensure stability. The complete armature is dynamically balanced. The commutator outer mica V-ring is protected with anti-creepage PTFE tape/ring.

1.3.2.1 Commutation

The function of the commutator in d.c. motor is to reverse the direction of current in each conductor as it passes from one pole to another, it helps to develop a continuous and unidirectional torque.

The current in particular conductor is in one direction when the conductor is

moving under the North pole and in the opposite direction, when it is moving under South 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. This process of reversal of current in a coil is termed as commutation. The period during which coil remains short circuited is very small. If the current reversal is completed by the end of short circuit then the cummutation is ideal. If reversal is not completed by that time, then sparking is produced between the brush and the cummutator which results in progressive damage to both. The rapid reversal of current in the armature core sets up a self induced emf, generally called reactance voltage, which hinders the reversal of current and tends to delay the current reversal in the coil. As a result, the current in the short circuit coil does not attain its full value in the reversed direction by the end of short circuit. This is the basic cause of sparking at commutator.

Figure 1.2 Armature



5

1.3.2.2 Method of improving commutation

Arrangement is made to neutralize the reactance voltage by producing a reversing e.m.f. in the short circuited coil under commutation. This reversing e.m.f. as the name shows, is an e.m.f. in opposition to the reactance voltage and if its value is made equal to the reactance voltage, it will completely wipe it off, thereby producing quick reversal of current in the short circuited coil which will result in sparkless commutation. For this purpose, special commutation poles (inter pole) are placed mid way between the main poles and wound with comparatively few heavy gauge Cu wire turns and are connected in series with the armature so that they carry full armature current. Their polarity should be opposite to the next main pole in the direction of rotation. The field produced by the interpole winding opposes the armature field.

The mmf developed by the interpole must be stronger than the armature mmf in

the neutral zone, because this mmf has to cancel the armature mmf and in addition induce an emf in short circuit coil which opposes reactance voltage and the voltage drop at the brushes.

1.3.3 Stator (Magnet Frame)

The high permeability cast steel or fabricated round magnet frame is machined to ensure alignment of the end shields, pole bores and axle way bores. Mainpole and compole coils are edge wound, curved epoxy insulated and bonded to pole bodies using epoxy resin. This improves heat dissipation and eliminates spring and support plates.

1.3.4 Rocker Assembly & Brush Holders

This motor is 6 pole type motor and the brush holders are mounted on the rocker ring that is fixed to the bearing bracket at commutator side by four bolts. The brush holders and carbon brushes can be inspected by rotating the rocker ring until each brush holder comes to the inspection window. The brush holders are mounted on the rocker ring by one insulating rod. Brushes can be changed without dismantling the motor. Flame retardent modified ETFE(fluonlex) cable is used for brush gear connections.

1.3.5 Arcing Horns

Arcing horns are provided near the brush holders on the rocker ring to minimize the damage in an event of a flash over.

1.3.6 Armature Bearing

The armature is supported on two grease lubricated cylindrical roller bearings at both the ends. Bearing may be greased intermediately. At the commutator side type NJ 324 + HJ 324 roller bearing is used and at the pinion side type NU 330 is used. The armature is located axially by the commutator end bearing, while the pinion end bearing is capable of taking care of any axial play between armature and frame.

Figure 1.3 Magnet Frame (Stator)

Figure 1.4 Rocker Assembly



6

1.3.7 Motor Suspension Unit

The axle suspension unit is made from cast steel and at the both ends cylindrical roller bearing housings are formed. Tapered roller bearings (TIMKEN) are used at both sides of tube. The suspension bearings are lubricated with grease. Grease is supplied through a grease nipple fitted to the suspension tube by a grease pump.

1.3.8 Pinion

The pinion which is shrunk fitted on the armature shaft, drives the loco axle through a spur gearwheel which is pressed onto the axle. It is made of high-speed carbon steel and case carburised.

1.3.9 Gear Case

The gear case is of welded steel construction and is two halves, which are bolted together. 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 sealing rings so as to prevent ingress of dust and any other foreign material and the escape of the gear lubricant.

1.3.10 Earth Brush and Earth Brush Holder

The earth brush holder is installed on the axle section of the magnet frame. The earth brush is made of metallic carbon and pressed to the axle by the coil spring.

1.3.11 Terminal Box

The 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 coming into the terminal box.

1.3.12 Cooling System

The traction motor is of the forced ventilation system and cooling air is supplied by the separate motor blower. One motor blower supplies cooling air to the group of three traction motors.

1.4 POWER SUPPLY ARRANGEMENTS

In traction position all the 6 traction motors M-1 to M-6 are supplied by the two silicon rectifiers in two groups of 3 motors each connected in parallel through contactors L-1 to L-6. The output from the rectifier assembly is taken through a smoothing reactor and is fed to the motor circuits. The direction of the rotation of the traction motor is reversed by reversing the connection to the motor field windings with the help of reverser thus enabling the locomotive to run in either direction.

Permanent field weakening resistance RPS 1-6 in parallel with the field windings of motors are used to prevent the ripple component of the current from passing into the field windings.

Three step field weakening resistance are connected through contactors for each motor. These resistances in steps control the field of the traction motor.

For electrical braking (rheostatic) the motors are disconnected from the silicon rectifiers and the armatures are connected to the braking resistances by means of the traction braking switch CTF 1-2. The exciting winding of the traction motors are connected in series and fed by the braking excitation transformer ATFEX and RSI-1.



7

Fig

ure

1.5

Pow

er C

ircui

t Dia

gram

(W

AG

-5)



8

CHAPTER 2

MAINTENANCE OF TRACTION MOTOR

Periodical maintenance is essential to ensure safety, reliability and continuous operation of traction motors over long time periods.

Following maintenance schedules are to be followed for traction motors (type HS-15250A).

Schedule Freight locomotives Pass./ Mail/ Exp. train locomotives

TI 20 days Every 3000 Km. or one trip which ever is later

IA 45 days 40 days

IB 90 days 80 days

IC 135 days 120 days

Work to be carried under each maintenance schedule is given below. 2.1 TRIP INSPECTION

Carry out the following inspection and fill up the proforma:

S.No.

Inspection & work to be carried out Standard value

Actual value

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

No abnormality

2. Check the inspection covers for proper attachment. Ok

3. Check the cables of all traction motors visually for any rubbing or damages.

No damage

2.2 IA SCHEDULE

Carry out the following inspections and fill up the proforma.

S. No.


Actual value

1. Clean inspection covers before removing them and check their condition.

Clean, ok

2. Examine the commutator thoroughly with the help of torchlight or hand lamp for a uniformly coloured, 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



9

S. No.


Actual value

4. Check commutator riser for solder run out. No damage

5. Check the following through inspection window up to possible extent.

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

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

Clean

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

No damage

5.4 Check the size of carbon brushes and if required, change the brushes which are likely to wear beyond the permissible limit before the next maintenance schedule.

(Exchange limit 30mm)

New- 64mm condemn -25mm

5.5 Check the flexible leads are firmly secured to the brush holders.

Secure

5.6 Check the tightness of rocker lock pin and rocker holding bolt.

Ok

5.7 Check the bellow net & bellow condition. Ok

5.8 Rotate rocker if found necessary. Ok

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

No abnormality


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 appearance for any abnormality.

No abnormality



10

2.3 IB SCHEDULE


S. No.


Actual value


Clean, ok



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

Clean

4. Check commutator riser for solder run out. No damage

5. Check the following through inspection window up to possible extent.

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


Clean

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

No damage

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

New- 64mm condemn -25mm


Secure

5.6 Check the tightness of rocker lock pin and rocker holding bolt.

Free

5.7 Check the bellow net & bellow condition. Ok

5.8 Rotate rocker if found necessary. Ok


No abnormality


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 appearance for any abnormality.

No abnormality



11

2.4 IC SCHEDULE


S. No.

Inspection & work to be carried out Standard value Actual value


Clean, ok

2. Blow out the interiors of the motor. Blown

3. Clean commutator with fluff – free cloth, moistened with a suitable solvent (such spirit).

Clean



5. Remove copper beads from the commutator surface with fine cloth and inspect visually commutator end banding and risers for abnormality.

Clean, no abnormality

6. Check interpole lead for any crack. ok

7. Clean hands with suitable solvents & cloth. Clean.

8. 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 3.44 kg. per brush

8.2 Check up spring pins by hand. ok

8.3 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 in format “A”. Replace them which are likely to wear beyond the permissible limit before the next maintenance schedule

(Exchange limit 30mm)

New – 64 mm

Condemn 25 mm


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 measure clearance and record in format ‘A’..

Ok, 11.5 – 13.5 mm

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

2 – 4 mm


Clean

8.10 Tight the rocker lock pin and rocker holding bolt. Tighten



12

S. No.

Inspection & work to be carried out Standard value Actual value

8. 11 Check the bellow net, there should be no foreign material or oil.

Ok


No abnormality

10. Lubricate inspection covers latches. Lubricate.

11. Check external cables of traction motors for wear and any rubbing mark.

No damage

12. Check connections of earth return brush. Ok

13. 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 any abnormality.

No abnormality

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

Available/ tighten

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

No abnormality

18. Replace the gaskets of inspection cover/ terminal covers if required.

Ok/ replaced

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

No abnormality

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

Intact.

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

No leakage

22. Grease both end armature bearings with pneumatic grease pump.

greased



13

FORMAT “A”

(i) Size of carbon brushes (in mm) : New – 64mm, Condemn- 25 mm (Exchange limit – 30 mm)

ACTUAL VALUES TM carbon Brush holder No. TM1 TM2 TM3 TM4 TM5 TM6

1. 2. 3. 4. 5. 6.

(ii) Brush holder spring tension : 3.44 kgf/ brush ± 10% (with new brush)

2.82 kgf/ brush ± 10%(with condemn brush)

ACTUAL VALUES TM carbon Brush holder No. TM1 TM2 TM3 TM4 TM5 TM6

1. 2. 3. 4. 5. 6.

(iii) Arc horn gap : 11.5 to 13.5 mm.

ACTUAL VALUES TM carbon Brush

holder No. TM1 TM2 TM3 TM4 TM5 TM6 1. 2. 3. 4. 5. 6.

(iv) Clearance between brush holder bottom and commutator : 2 to 4 mm

ACTUAL VALUES TM carbon Brush

holder No. TM1 TM2 TM3 TM4 TM5 TM6 1. 2. 3. 4. 5. 6.



14

CHAPTER 3

OVERHAULING

Overhauling 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 months IOH 54 months or 6 lakhs kms.

which ever is earlier 36 months or 4 lakhs kms. which ever is earlier.

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

6 years or 8 lakhs kms. which ever is earlier.

Details of work to be carried out during overhauling is given as under:

3.1 GENERAL

First of all remove the bogie from the vehicle.

Remove as much dirt as possible particularly around the inspection covers, the axle cap 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/ TESTING

Bring 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 IR values 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 done during 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.



15

3.3 GENERAL CLEANING 3.3.1 Cleaning Material 3.3.1.1 Cloth

Cloth 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, commutator

etc. since left over flufts or fibres may cause failure. 3.3.1.2 Compressed air

Dry compressed air should be used to blow out traction motor.

3.3.1.3 Cleaning solvents Warning As all solvents are toxic to a varying degree, the minimum amount of solvent should

be used and the workshop area should be well ventilated. Some solvent when heated become more toxic and therefore, the cleaning of hot

surface should be avoided. Smoking should be prohibited in all areas where solvents are used, since some are

highly inflammable. When using solvents, the operator should wear plastic gloves and not rubber since

some 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 are

not allowed to come in contact with windings. 3.3.2 Cleaning methods

Cleaning of accessible parts of traction motor should be carried out by wiping the parts with a dry cloth or, if necessary, with a cloth lightly moistened with the above recommended solvents.

Cleaning of inaccessible parts of machines, for example, behind the field coils should be carried out by spraying the part with a solvent. The spray of solvent must be kept moving over the surface.

The spray cleaning of the field system of a traction motor should not exceed 15 minutes and spray rinse 3 to 5 minutes.



16

3.4 DISMANTLING 3.4.1 General

Bring 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 grease supplied etc.) must be observed strictly.

3.4.2 Flow Chart for Dismantling en 3.4.3 Disassembly of Pinion From Armature Shaft

Loosen the pinion-locking nut so that clearance of 3 to 4mm is made between the nut and pinion.

Remove the pinion by oil injection method as described below.

1. By oil injection method

A groove is machined around the armature shaft extension on the pinion seating and is connected by vertical drilled hole to a tapped hole parallel in the end face of the shaft. This is provided for the removal of the pinion by oil injection, oil under high pressure being supplied by a oil injector pump.

Inspection cover

Carbon brush

Pinion nut

Pinion

Outer bearing stopper (pinion end)

Armature

Magnet frame

End Shield (PE)

End shield (CE) Rocker ring Brush Holder



17

The tapped hole in the shaft is sealed with a rubber screwed plug to prevent gear lubricant from entering and blocking the oil ways. Follow the procedure mentioned below:

Remove all traces of gear lubricant from the pinion, the shaft end and the oil 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 pipe and 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 oil and resistance of pumping is felt.

Fit the pump handle and continue pumping raising the pressure gradually and pausing after each stroke to let the pressure built up at the pinion seating.

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 oil

In some cases, difficulties may be faced in removing the traction motor pinion from shaft due to leakage of oil during extraction of pinion by oil injection method. In such type of case, follow the methods, mentioned below respectively.

Material and equipment required i. ‘M’ seal putty : For sealing the oil leakage. ii. Hot oil : For heating the pinion. iii. Oil injection equipment iv. Hydraulic Ram

Figure 3.1 Oil Injector To Remove Pinion

PINION PINION NUT

OIL TANK

HIGH PRESSURE PIPE

ADAPTER

INJECTOR BRACKET

PISTON



18

Procedure - I

By applying ‘M’ seal putty 1. 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 mating

points 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 to

6.

Procedure – II

By 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 the

pinion. 4. If the pinion is not getting extracted, apply oil pressure simultaneously by using

oil injection. For this purpose, a small metallic spacer may be used in between shaft end and ram of the puller so as to enable fitting of oil injection plug into the shaft.

NOTE

i. The procedure II of pulling and heating the pinion to be used only after oil

injection with ‘M’ seal fails repeatedly. ii. The use of excessive pressures may cause the pinion to be ejected violently, it

may 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 to

prevent the ingress of foreign material. v. Protect the pinion bore and shaft extension from damage and corrosion.



19

3.4.4 Disassembly of Outer Bearing Stopper (pinion side) Dismount the outer bearing stopper (pinion side) by using the exclusive tools as

shown in fig. 3.2

Item No. Description Tool mark Qty. 1. Nut TL-4 1 2. Double end stud TL-5 6 3. Support disk TL-6 1 4. Nut M16 -- 6 5. Ram with oil power pump -- 1

3.4.5 Disassembly of Armature 3.4.5.1 Preparation

The armature is to be dismounted from the stator with the bearing bracket (end shield) at the pinion side kept fitted. Before dismounting the armature, make preparation as follows:

Remove all the carbon brushes from the brush holders by disconnecting terminal bolts of carbon brushes lead wires and rotating rocker ring.

After removing the carbon brushes, wind a press board on the commutator for preventing the commutator surface from being scratched.

Dismount the bearing cover from the bearing bracket (CE end shield) utilizing the tapped hole for pulling out.

Dismount the outer bearing stopper (CE) and thrust collar of roller bearing (CE) from the armature shaft.

Figure 3.2 Outer Bearing Stopper Pulling Out (PE)



20

3.4.5.2 Disassembly

After completion of the preparation for disassembling the armature, keep the motor upright with the commutator side downside.

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 end shield).

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

Place the armature dismounted from the stator on a wooden table 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 in dia.) into the bearing bracket bolt hole and extract the bearing bracket crosswise with it lifted and supported by crane.

Extract the bearing bracket in arrow mark

direction.

Write serial number with white paint to PE end shield and armature.

Figure 3.3c

Figure 3.4

Figure 3.3a

Figure 3.3b

Bearing bracket



21

3.4.7 Disassembly of Commutator Side Bearing Bracket (end shield)

Dismount the CE bearing bracket (end shield) from the magnet frame utilizing the tapped 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 with white paint to CE end shield.

3.4.8 Disassembly of Rocker Ring

Remove one special reamer bolt (dowel bolt) that is fixing the rocker ring to the magnet frame commutator side. (This work is already performed during removal of carbon brushes for rotating the rocker ring).

Remove the rocker from the magnet frame and write serial number with white paint

to rocker ring and magnet frame. 3.4.9 Disassembly of Armature Bearings 3.4.9.1 Disassembly of roller bearing inner ring at pinion side

When the bearing bracket (end shield) at the pinion side is removed from the

armature, 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 and

bearing inner ring simultaneously by using the exclusive tools as shown in the fig. 3.5.

Item no. Description Tool mark Qty. 1 Hook TL-2 2 (1 set) 2 Keeper plate TL-3 1 3 Nut TL-4 1 4 Double end stud TL-8 4 5 Support disk TL-6 1 6 Nut M24 -- 4 7 Ram with oil power pump -- 1 8 Bolt M24 L40 -- 2

Figure 3.5 Bearing Inner Ring and Inner Bearing Stopper Pulling out (PE)



22

3.4.9.2 Disassembly of bearing inner ring at commutator side

When the bearing bracket at the commutator side is removed from the magnet frame, the bearing inner ring and inner bearing stopper are fitted on the armature shaft commutator 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 (1 set) 2 Keeper plate TL-3 1 3 Nut TL-4 1 4 Double end stud TL-14 4 5 Support disk TL-6 1 6 Nut M24 -- 4 7 Ram with oil power pump -- 1 8 Bolt M24 L40 -- 2

3.4.9.3 Extraction of bearing outer ring at pinion side

On the bearing bracket(PE end shield) removed from the armature, the roller bearing outer ring is fitted. Dismount it by using the exclusive tools as shown in fig. 3.7.

Figure 3.6 Bearing Inner Ring and Inner Bearing Stopper Pulling Out (CE)

Figure 3.7 Bearing Outer Ring Pulling Out (PE)

Item No.

Description Tool mark

Qty. Item No.


Qty.

1 Nut TL-4 1 4 Distance piece TL-9 1 2 Puller TL-18 1 5 Support disk TL-6 1 3 Absorber TL-10 1 6 Stand TL-19 1 7 Ram with oil power pump -- 1

Outer race

Bearing bracket

piston

Ram



23

3.4.9.4 Extraction of bearing outer ring at commutator side

On the bearing bracket (CE end shield) removed from the armature, the roller bearing outer ring is fitted. Dismount it by using the exclusive tools as shown in fig. 3.8

3.5 CLEANING OF ARMATURE BEARINGS

To clean the dismounted armature bearings, put them into a vessel containing kerosene heated upto about 60° C without degreasing and leave them as they are in kerosene for more than 10 minutes. After that wash them roughly and take them out of the vessel. Then blow away sticking grease with compressed air.

Repeat the procedures more than twice, and then, wash the bearings finally with clean kerosene having ordinary temperature and blow away adhering kerosene completely with air.

For the final washing, always use new kerosene and do not use heavily oxidised or foul one.

Wash hands with a degreasing agent such as ethyl alcohol/ petrol carefully for preventing the bearings from getting rusty when handling after the final wash.

3.6 CHECKING OF ARMATURE BEARINGS

Check 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 make sure that there is no abnormality.

If any abnormality observed in either inner or outer ring, replace with new set of bearings.

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 rings should be assembled.

Note : Whenever a new bearing is provided, the date of commissioning of bearing should be engraved on the bearing.

Figure 3.8 Bearing Outer Ring Pulling Out (CE)

Outer race

Bearing bracket

piston

Ram

Item No.


Qty.

1 Nut TL-4 1 2 Puller TL-15 1 3 Distance piece TL-16 1 4 Absorber TL-17 1 5 Support disk TL-6 1 6 Stand TL-19 1 7 Ram with oil power

pump -- 1

1

4

5

6



24

3.7 CLEANING OF ARMATURE, STATOR AND OTHER PARTS

Clean the armature thoroughly by clean and dry compressed air.

Metallic portion of armature shaft to be cleaned with white spirit or ORION 510 diluted 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 compressed air.

Cleaning of spaces between & behind the field coils is to be done when magnet frame (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 ARMATURE

Check visually for any damage, both side resiglass bond, pinion seat for any abnormality.

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 Shaft

Ultrasonic testing of armature shaft is to be carried out to detect any flaw etc. to avoid 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 Surface

The necessity of reworking the commutator surface is determined depending on its condition and the judgement. It must be judged observing the condition of commutator surface carefully and can be maintained as following.

3.8.2.1 Grindstone

Applying “Grindstone” must rework the commutator exhibiting the following conditions: Where the commutator surface is heavily blackened. Where the commutator surface is rough owing to

minor flashover.

Procedure:

Put the armature on a lathe and apply grindstone. After completion of applying a grindstone, blow away the stone powder with air and check carefully the groove inside, between commutator bars to be sure that there is no abnormality.

Figure 3.9 Grind Stone



25

3.8.2.2 Turning of Commutator surface In case where the following conditions are recognised, apply turning to the

commutator surface:

If eccentricity, unequally in diameter, high-bar, low-bar etc are generated in commutator, cut the commutator as per given table.

Item Corrective Limits After Turning

Eccentricity Not more than 0.1 mm. 0.03 mm. Inequality in diameter Not more than 0.06 mm. 0.006 mm.

High, low-bar Not more than 0.005 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 δw’ (depth of stepped portion) exceeds 0.1mm at the maximum, it requires cutting work.

In case where it is impossible to rework by a grindstone because the commutator surface is heavily rough.

The degree of turning of commutator surface should be judged according to the conditions 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 as

shown below in figure 3.10

Figure 3.10 Resurfacing of Commutator

Push the shaft end of armature shaft on the commutator side by the centre of lathe, align the armature shaft by using the bearing fitting portion A, on the pinion side as reference and chuck the shaft end on the pinion side. Apply a steady rest to the bearing-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.

Commutator surface

Centre

Steady rest

Chuck

A



26

3.8.2.4 Mica under Cutting and Chamfering When the commutator surface is cut, the slot between the commutator bars

shallows and chamfering of commutator bars, become too small. Therefore after cutting, under cutting, chamfering should be performed with suitable tool. This is to be done as per RDSO SMI No. 31. Details of under cutting & chamfering are shown below in figures 3.11 to 3.14.

3.8.2.5 Cleaning On the completion of cutting the commutator surface, clean by blowing air

directly to it. To protect the commutator surface from injuring, a press board and polyester tape should be winded.

3.8.3 Creepage Area Surface

The creepage area surface, should be kept in good condition. The area should be cleaned and painted with anti track varnish or E 233 varnish. The procedure for painting 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 no dabs or overlapping areas.

Take care to avoid getting varnish into commutator slots or the relief at the bottom commutator neck.

3.8.4 Varnishing of Armature

Bake the armature for 2 hours at 80 deg. C and varnishing to be done with anti-track varnish 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 be minimum 10 M ohms.

Figure 3.13 Details of under cutting and chamfering

Figure 3.11 Chamfering Tool Figure 3.12 Chamfering Work

Figure 3.14 Example of under cutting

A. Correct B. Excessively large C. Excessively deep D. Left unchamfered E. Left ungiven under cutting



27

3.8.5 Cleaning of the Surface of Glass Tape

Clean the surface of glass bind and the side of commutator bars by wiping with clean cloth containing petrol.

Check the condition of resiglass binding.

After keeping the armature at room temperature for 2 hours or longer, dry its cleaned surface with portable dryer.

3.8.6 Cleaning of Surfaces of Commutator and Teflon Ring

Remove the protection cover from commutator surface.

Check whether varnish, finishing varnish or any other article does not remain in grooves, 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 Tests

One of the most important “condition monitoring” tests, is the bar to bar resistance check on traction motor. This is very important test to detect defective joints in commutator risers, open or short circuited coils. This test should be done with a precision 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 Test

This test is carried out for detecting cross connection of leads, short circuits or open circuits 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 Measurement

The measurement of tan-delta (dissipation factor) is carried out for checking insulation between armature shaft and winding. The measurements should be carried out between the commutator (with all segments shorted by a copper wire) and the armature 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 Test

Carry 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 HOL DERS

Remove and clean all 06 nos. brush holders.

Repair & clean flash marks on brush holders.

Check the spring tension, if required adjust.



28

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 the same.

Check the condition of threads of pig tail fixing holes on brush pocket and tap it if required.

Apply bectol red varnish on pocket from outside area.

Clean rocker ring (BHRR).

Check the condition of Teflon sleeve of insulating rod assembly, if required replace it.

Check the tightness of all 06 nos. insulating rod assemblies.

Check the tightness of positive and negative insulating rod and also check their stud 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, replace the 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 and record.

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/ablong replace 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 at 100 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 suspension tube as per SMI-207.

Perform H.V. test by applying 2.5 kv a.c. supply for one minute and measure the leakage 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 ensure the temperature rise at joints by hands. This is to be carried out as per RDSO SMI no. RDSO/ELRS/SMI/ 151 dtd. 08.12.92 and also record the voltage drop.



29

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 with torque wrench as per RDSO mod. WAM4/165.

Provide RTV to MP fixing bolts-03 nos. and terminal insulators-04 nos. at motor suspension 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 SHIELD S)

Clean the PE & CE end brackets

Check 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 COVERS

Clean 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 ASSEMBLY

Dismantle 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 PINION

Clean 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 any other defect.

Pinion should be checked with red dye penetrating test (RDPT) for any crackness on its teeth/body.

Measure dimension ‘k’ over the specified teeth as per proforma and note the average value of 8 different measurements by a micrometer of suitable size. It should be within specified limit. If ‘k’ value is found less than specified value then scrap the pinion and fit new pinion.

Check the “p” value of pinion teeth, it should be less than 0.4mm.



30

3.15 REASSEMBLY OF ARMATURE BEARINGS 3.15.1 Preparation

Reassemble the armature bearings carefully after cleaning and be careful with ingress 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 never mix with grease of other brands.

Fill grease in the bearing bracket and bearing cover at the PE & CE side as shown in fig.3.15 (PE side 925 gm. and CE side 864 gm.)

3.15.2 Reassembly of Roller Bearing Inner Ring at Pinion Side

Wipe carefully the bearing inner ring assembling part of the armature shaft and fit the inner bearing stopper and inner ring in place in following order:

Put the inner bearing stopper and bearing inner ring into the oil bath containing kerosene heated up to 110 to 120°C for heating them and shrink fit on the armature shaft.

When shrink fitting them on the armature shaft, press them by hand till they cool so that 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 of armature,

After each part has been fitted on the shaft, apply grease thinly to the surface for rust prevention purpose.

Figure 3.15 Bearing brackets & Covers PE & CE

Figure 3.16

Assemble the parts without producing gap at these sections

Inner bearing stopper

Inner ring Outer bearing stopper



31

3.15.3 Reassembly of Roller Bearing Outer Ring at Pinion Side

Pressure fit the outer ring to the bearing bracket by using the exclusive tools as shown 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.


Qty. Item No.


Qty.

1 Nut TL-4 1 4 Stand TL-19 1 2 Hook TL-11 1 5 Ram with oil power pump -- 1 3 Support disk TL-6 1

3.15.4 Reassembly of Roller Bearing Inner Ring at Commutator Side

Wipe carefully the bearing inner ring assembly part of the armature shaft and put the inner bearing stopper and bearing inner ring in position in following order:

Put the inner ring and inner bearing stopper into the bath containing kerosene heated up to 110 to 120°C for heating them and shrink fit on the armature shaft.

When shrink fitting them onto the armature shaft, press them by hand till they cool so that gap is not produced at the stepped part of inner bearing stopper and inner ring as shown in fig. 3.18.

Figure 3.17 Inserting bearing Outer Ring into Bearing Bracket (PE)

Figure 3.18 Assembly of Bearing Inner Ring (CE)

Outer race

Bearing bracket

Grease

Piston

Inner bearing stopper

Inner ring



32

3.15.5 Reassembly of Roller Bearing Outer Ring at Commutator Side

Pressure fit the outer ring to the bearing bracket by using the exclusive tool as shown in fig. 3.19

Never fit the outer race while striking by hammer without using the exclusive tool; otherwise the bearing may damage.

3.16 REASSEMBLY OF TRACTION MOTOR

Reassembly can be made easily by reversing the procedure of disassembly. Prior

to reassembly, prepare all parts and tools necessary for reassembly correctly. 3.16.1 Preparation for Reassembly

Before 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 frame with the inner race, bearing stopper and outer race.

Wind a press board on the surface of commutator for protection of the surface and make preparation for reassembly.

3.16.2 Tightening Torque of Each Bolt and Nut

Check each bolt and nut for looseness and retighten as required. Each bolt and nut should be tightened with tightening torque as shown in table below.

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

Figure 3.19 Inserting Bearing Outer Ring into Bearing frame (CE)



33

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 Overhauling

Sr. No.

Description Qty. Remarks

1. Lock washer 1 Pinion

2. Lock washer 1 Outer bearing stopper

3. Gasket 2 Net of air inlet

4. Gasket 1 Inspection cover of magnet frame

5. Gasket 1 Cover of magnet frame

6. Rubber plug 1 Armature shaft

7. Roller bearing 1 Commutator side (if required)

8. Roller bearing 1 Pinion side (if required)

9. Carbon brush 18

10. Earth brush 1 Earth brush assembly

11. Brush holder As required

Replace if required

12. Earthing brush holder 1 set Earth brush (if required)

13. Grease -- Servogem RR-3/ Lithon-3/ Shell Alvania grease no.3

3.16.4 Flow Chart for Assembly

Magnet frame

Armature

Deflector (pinion end)

Pinion

Pinion nut/lock plate

Carbon brushes

Inspection covers

Bearing bracket (CE)

Rocker ring

Brush holder

Bearing bracket (PE)



34

3.16.5 Installation of Brush Holders & Reassembly of Rocker Ring

Reassemble the brush holders and insulating rods on rocker ring.

The neutral point mark and serial number are carved on rocker ring and magnet frame. When installing the rocker ring to the magnet frame, combine ones that have the same number.

3.16.6 Reassembly of commutator side bearing bracket

Mount the CE bearing bracket to the commutator side of magnet frame.

3.16.7 Reassembly of Pinion Side Bearing Bracket

Mount the bearing cover to the bearing bracket and tighten the bearing cover by the bolts

Insert a round steel bar to the bolt hole of bearing bracket, lift the bearing bracket by a crane and mount it to the pinion side of armature shaft as shown in fig.3.20

3.16.8 Reassembly of Armature

Keep the magnet frame up right. Don’t tilt it. If the magnet frame is left tilted, when inserting the armature into the magnet frame, the commutator and/or armature coil may contact the brush holder, main pole coil, interpole coil etc. and may damage them.

Insert the armature into magnet frame kept upright, with the armature lifting hook installed on the shaft end at pinion side and the armature lifted by crane turning the commutator side downward.

When inserting the armature, screw guide bolts into bearing bracket clamping built holes in the magnet frame as the guide for the bearing bracket.

Lower gently the armature keeping lifted by crane. Do not lower suddenly and insert the armature assembly unduly; otherwise bruise is caused in the bearing inner race face.

When the bearing bracket has been fitted to the due part of magnet frame, remove the guide bolt and clamp the bearing bracket with the bolts.

Figure 3.20



35

Tighten 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 turned smoothly, but if it fails to turn smoothly, re-tighten the bearing clamping bolts uniformly.

3.16.9 Reassembly of Bearing Stopper at Commutator Side

After the armature has been assembled in place, lay the motor, install the thrust ring for cylindrical roller bearing of roller bearing inner race at the commutator side and bearing stopper, tighten the bolt M16L35 and bend the lock washer for fixing.

3.16.10 Reassembly of Commutator Side Bearing Cover and Pinion Side Outer Bearing Stopper

Mount the bearing cover to the CE bearing bracket and tighten the bearing cover by the bolts.

Mount the outer bearing stopper on the pinion side by shrinkage fit (heating temperature 110 – 120°C).

3.16.11 Shrink Fitting the Pinion

Wash and clean the pinion with kerosene to remove the grease and oils. Then apply a thin coating of red paint (Fe2O3 powder) on the bore surface of the pinion, putting together the tally mark on the shaft and pinion, force fit the pinion lightly on the shaft. Then measure the dimension `lo’ with depth micrometer and record `lo’ as shown in figure 3.23.

Remove the pinion and check the bedding between the pinion and the shaft. It is necessary that more than 90% of entire contact area to be actually in contact. If there 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 to a temperature rise of 140 ±10°C. above room temperature. It is most important to keep the temperature of oven/ induction heater/ oil bath accurate.

Remove the pinion from oven/ induction heater/ oil bath and remove oil from pinion surface by air blowing as fast as possible (if immersed in oil bath heater).

Figure 3.22

Figure 3.23

Turn the armature slowly

Shaft end

Armature

Guide bolts

Magnet frame

Figure 3.21

I0-I



36

Perform shrink fitting of pinion immediately by putting together the tally marks on the armature shaft and the pinion. Tighten the pinion nut lightly and allow to cool naturally.

After the pinion has cooled off completely, release the pinion nut. Measure and record “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 as follows :

I 0 - l = entering allowance of pinion (advancement) = 1.92 to 2.00 mm. where l0 = dimension before shrink fitting l = dimension after shrink fitting

After making sure that the pinion entering allowance is satisfactory, insert the lock plate and tighten the pinion nut.

If the pinion entering allowance is not sufficient, remove the pinion and perform shrink fitting again. This must be done until perfect result have been achieved.

3.17 FITTING OF CARBON BRUSHES Adjust 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 brush holders.

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 LOAD

Place the TM at light run testing panel.

Make the supply connection (armature and field connections in series) and ON the variable d.c. supply.

Increase voltage gradually till the TM gains the speed 895 rpm, allow it to run and check 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 the temperature of bearings, the steady state temperature rise should not exceed 35 to 45 deg. C above ambient.

3.19 FINAL ASSEMBLY CHECKING

Check 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.



37

3.20 INSPECTION AND TESTING PROFORMA FOR OVERHAULIN G HITACHI TRACTION MOTOR TYPE HS – 15250A A- Stage : Pre-inspection

Sr Inspection/ Test Standard value Actual value 1. Check insulation resistance with 1 kV

megger between – a) Main pole circuit to earth b) Inter pole circuit to earth c) 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. side b. Vibration c. Ovality of the armature

0 – 35 dBN 0-35 dBN no vibration 0.05 mm (Max.)

3. Check distance between outer surface of pinion & shaft face.

Recorded

B - Stage : Overhauling of Magnetic Frame (Stator)

Sr Inspection/ Test Standard value Actual value 1. Do the baking before and after varnishing of

stator with anti-track varnish or E 233 red varnish a) Pre-heating for 5 hours at 100 deg. C b) Baking for 3 hours at 100 deg. C

Done

2. Check insulation resistance with 1kV meggar between

a) Main pole circuit to earth b) Inter pole circuit to earth c) Main lead circuit to earth d) 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 – 0.0097 Ohm

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

0.0061 – 0.0074 Ohm

5. Check the tan delta of MP, IP Recorded

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

512.5 – 512.9 mm 519.8 – 520.2 mm

7. Distance of Magnet frame between connecting faces 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.



38

Sr Inspection/ Test Standard value Actual value

9. Check top lug thickness 38 – 40 mm

10. Distance between lug mounting bush and stator collar.

16.5 – 18 mm

11. Check the PE & CE housing e/ shield bore dia (PE) (CE)

696 + 0.080 mm + 0.00 710 + 0.080 mm + 0.00

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

Recorded 4.28 – 4.68 V

13. Check the distance between motor lugs. 304.25–305.75 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 roller bearing.

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 1kV meggar.

100 MΩ (min.)

C. Stage : Overhauling of brush holder/rocker ring.


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

3.10 to 3.78 kgf max.

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 9049

64 mm

2-4 mm

4 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 applying 3 KV A.C. supply for one minute and measure the leakage current.

10 milli amps

(maximum)

5. Check the arcing pointer gap. 11.5 – 13.5 mm



39

D- Stage : Overhauling of Armature & Commutator

Sr 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.)

2.5mm (max.)

4. Mica groove width 1.1 mm

5. 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 mega ohms (minimum)

7. Check tan delta at 1 KV

and at 3 KV

Less than 4%

Less than 6%

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

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

+/-3 SD.

10. Shaft

i. 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 mm

120 + 0.059 mm

+ 0.037 mm

perfectly 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. O.K.

14. 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 or discolouration

No such symptoms

Good



40


16. i) Radial clearance of free bearing when new. Pinion end Commutator end

ii) Actual radial clearance after assly. Pinion end Commutator end

iii) PE side 1) Bearing ID: 2) Bearing seat shaft dia

3) Interference

iv) CE side 1) Bearing ID 2) Bearing seat shaft dia 3) Interference

v) Check housing dia. of bearing. PE side (if new bearing provided) CE side

0.165 – 0.210 mm 0.155 – 0.195 mm

0.104 –0.177 mm 0.066 – 0.147 mm

150+ 0/-0.009 mm 150 + 0.068 mm + 0.043 mm

0.046 to 0.059 mm

120 +0/-0.009 mm 120 + 0.059 mm + 0.037 mm

0.041 to 0.050 mm

320 – 0.010 mm – 0.046 mm 260 – 0.009 mm – 0.041 mm

E- Stage : Pinion Inspection and fitting


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 cracks

4. 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 to 2.00 mm

8. Check the ‘k’ value of pinion between

3 teeth for 18 teeth pinion



93.293–94.741mm

95.88– 96.019mm

131.461–131.607 mm

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



41

F Stage : Final Assembly


1. Check ovality of commutator in assembled TM. 0.04 mm (max.)

2. Check the insulation resistance with 1 KV megger between –

a) Main pole circuit and earth

b) Inter pole circuit and earth

c) Main pole and Inter pole

10 mega ohms (Minimum)

3. Run the Traction Motor at 895 RPM on no load for two hours (in both direction) & check the following

a) Vibration

b) Bearing Noise i) PE side

ii) CE side

c) Temp. rise of bearing i) PE side

ii) CE side

d) SPM reading to be recorded

i) PE side

(0-35 dBN for old bearing)

ii) CE side

(0-35 dBN for old bearing)

No Vibration

Normal Noise

Normal Noise

35-40 Deg. C

(above ambient)

10 – 20 dBN (Green Zone) (New Bearing) 10-20 dBN (Green Zone) (New bearing)



1

3.21 SPECIAL TOOLS FOR TRACTION MOTOR OVERHAULING

Tools Combination of tools Tool No.

Description Outer bearing stopper pulling out (PE)

Bearing inner ring pulling out (PE)

Bearing inner ring pulling out (CE)

Bearing outer ring pulling out (CE)

Bearing outer ring pulling out (PE)

Inserting bearing outer ring into bearing bracket (PE)

Inserting bearing outer ring into bearing frame (CE)

Oil injector to remove pinion

Common tool

Qty. (Nos.)

TL-2 Hook 2

TL-3 Keeper plate 1

TL-4 Nut 1

TL-5 Double end stud 4

TL-6 Support disk 1


TL-9 Distance piece 1

TL-10 Absorber 1

TL-11 Hook 1

TL-12 Hook 2


TL-15 Puller 1

TL-16 Distance piece 1

TL-17 Absorber 1

TL-18 Puller 1 Spanner for pinion nut 1 Nut M16 4 Nut M24 4

TL-25

Bolt M24L40 2 Stand 1 Pump 1 Ram 1 Hose 6

TL-19

Oil injector 1 set Adapter 1 Grease gun 1 TL-115 Commutator stone 1

Maintenance H

andbook on Hitachi T

raction Motor (H

S-15250A) of E

lectric Locom

otives

January, 2005

CA

MT

EC

H/E

/2005/TM

(H)/1.0

4

2



43

CHAPTER 4

COMMON FAILURES

S.N. Failures Possible Cause Suggested Remedies

i. Carbon brushes of different grades & sizes.

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. Unbalance of brush current i.e. colour change in pig tail of brush.

Clean the commutator surface and polish it with 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.

1. Commutator Flashed/poor commutation

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.

i. Armature insulation level less or IR value zero.

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

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

Improve the IR value of field ciecuit and if required, replace the traction motor, check the field coils and rectify the defect & TM O/H to be done.

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

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

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

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.



44


v. Carbon brush pig tail broken & flashed.

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

vi. Traction motor inter connection leads insulation damaged.

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

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

Check and attend the damaged cable and secure all the cable properly providing the proper rubber gaskets.

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

Clean the concerned traction motor & blow it with dry compressed air and 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 attend the same. Tightness of cable connections to be checked.

x. Insulation of brush holder insulator damaged.

Check and apply insulating varnish or replace the brush holder insulator if required.

i) Armature winding short circuited or commutator segments shorted.

Replace the defective traction motor and rectify the defect.

ii) Motor suspension unit taper roller bearing defective/jam causing traction motor rotating jam.

Replace the concerned traction motor. Check the taper roller bearing and attend.

iii) Traction motor armature bearings seizure.

Replace the traction motor. Check the armature bearing clearances, grease condition and roller condition etc. and replace the bearing set.

3. Overload relay tripping due to more current drawn by traction motor.

iv) Axle box bearing seizure or bearing damaged.

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



45


i) Pinion teeth broken or damaged.

Replace the traction motor and check the pinion fitting & pinion teeth, if required, pinion to be replaced. Proper procedure to be followed for removing & fitting of the pinion.

ii) Any foreign material in the traction motor.

Replace the traction motor and remove the foreign material and check the health of traction motor and attend the defect.

4. Abnormal noise coming from traction motor.

iii) Armature bearing clearances more or damaged.

Replace the traction motor and overhaul. Check all the bearings carefully and replace with new one if required.

i) Armature winding coil or field coil or IP coil open circuited.

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

ii) Stator MP & IP connection lead broken flashed or burnt.

Check the motor and attend the defect, if required, traction motor to be replaced.

5. Traction not effective i.e. particular wheel not rotating.

iii) Traction motor cable connection flashed & parted in terminal box.

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

6. Armature shaft broken

Armature shaft may broken/sheared off due to existence of any flaw previously.

Ultrasonic testing of armature shaft to be carried out during every overhauling to prevent such type of failure.



46

CHAPTER 5

DO’S AND DON’TS 5.1 DO’S

1. 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 tightening torque value.

3. Always ensure that the modification/ special maintenance instructions are being followed.

4. Ensure that the new carbon brushes are of the same grade, as the old ones, while replacing 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 while assembling the traction motor parts.

7. Ensure that the oven/ induction heater/ oil bath heater is working at the recommended temperature.

8. Always use Shock Pulse Meter (SPM) for monitoring the condition of bearings and 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 for cleaning the traction motor.

11. Always slip a thin clean pressboard between brush holder and the commutator while 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 the commutator when refitting a brush holder.

13. Ensure that the lubricating oil/ compound of approved make are in use.



47

5.2 DON’TS

1. Don’t use cotton waste or fluffy cloth for cleaning brush gear, commutator since left 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 component authority.

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 cleaning inside 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 stepped wear 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 because of the possibility of rollers skid, which can cause scuffing of the track and roller surface and premature bearing failure.

14. Don’t forget to refit the plug into the oil injection hole immediately after removal 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 the armature is set, it shall be supported by the armature core and never with the commutator or glass bind.

17. Don’t remove the film on the commutator surface, unless there is special reason such as bad commutation, abnormal wear of carbon brush and so on. (Film adjustment 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 brush may be broken or hands injured).



48

ANNEXURE – A

Special Maintenance Instructions for Traction Motor type HS-15250A.

Sr. No. SMI No. Description

1. RDSO/ELRS/SMI/6

Dt. 30.12.77 & Dt. 22.02.78

Resurfacing of commutator of traction motors and its amendments.

2. RDSO/ELRS/SMI/25

Dt. 24.07.78

Millivolt drop or micro ohm resistance test on traction motors.

3. RDSO/ELRS/SMI/29

Dt. 08.1978

Resurfacing of commutator speed, feed & tool.

4. RDSO/ELRS/SMI/31

Dt. 24.10.78

Undercutting and chamfering of traction motor commutators.

5. RDSO/ELRS/SMI/51

dt. 30.04.1979

Bar-to-bar conductor resistance and equiliser resistance test on traction motors.

6. RDSO/ELRS/SMI/128

dt. 19.06.85

Tan delta measurements on traction motor armatures.


dt. 23.11.92

Ultrasonic testing of armature shaft of Hitachi Traction Motor type HS 1050Er/HS15250A.


dt. 8.12.92

Testing of brazing joints of field coil circuit of traction motor type TAO 659 & HS 1050 Er/HS 15250A.


dt. 29.06.93

Rewinding procedure for armature of Hitachi traction motor type HS 1050Er/HS 15250A.


dt. 11.04.94

Measurement of backlash of traction gears.

11. RDSO/ELRS/SMI/181 dt. 30.05.96

Neutral setting of BHRR of traction motor by electrical method known as “Kick Method”.

12. RDSO/ELRS/SMI/182 dt. 03/04.06.96

The skin that forms on the surface of commutator over the area covered by the brushes operating on it, is called ‘Patina’. It is advisable to remove this film.

13. RDSO/ELRS/SMI/183 dt. 13.12.96 & 19.03.98

Procedure of proper tightening of suspension tube fixation bolts fitted on traction motor type TAO-659 and HS 15250A & its amendment No.1.

14. RDSO/ELRS/SMI/186 dt. 15.05.97

Bonded rubber sand witch mounting for nose suspension of traction motors.


dt. 19.07.2000

Preventive measures to arrest the failures of commutator end armature bearing type NH 324 of T.M. type 15250 A.



49

ANNEXURE ‘B’

Modification Sheets of Traction Motor Type HS 15250A

Sr. No.

Modification Sheet No.

Description

1. RDSO/WAG5/23

Dt. 29.1.98

Provision of replaceable bushes in traction motor gear case mounting lugs of traction motor type HS 15250A.

2. RDSO/WAG5/24

Dt. 29.1.98

Adoption of modified commutator end bearing bracket on traction motor type HS 15250A.

3. RDSO/WAG5/25

Dt. 29.1.98

Provision of grease outlet i.e., drain hole in ‘CE’ outer bearing cap of traction motor type HS 15250A and procedure for regreasing of armature roller bearings (PE&CE).

4. RDSO/WAG5/27

Dt. 27.2.98

Adoption of modified insulating rod assembly (for positive & negative support) and modified fixation arrangment of BHRR flexible cable interconnectors for traction motor type HS 15250A.

5. RDSO/WAG5/28

Dt. 27.2.98

Adoption of modified brush holder insulator assembly (insulating rod) and brush box along with provision for arcing studs on BHRR assembly of traction motor type HS 15250A.

6. RDSO/WAG5/31

Dt. 30.3.98

Modification in the pinion end portion of armature shaft of traction motor type HS 15250A/HS1050Er.



50

REFERENCES

1. Manual of AC Traction Maintenance & Operation (ACTM) Vol.III, Electric Rolling Stock 1994.

2. Maintenance Manual for 25 kV, 50 C/S AC Electric Locomotive WAG-5 Vol. I

1993 published by CLW. 3. Maintenance Manual of Model HS 15250A Traction Motor published by M/S

Hitachi, Ltd. 4. Field study and Literature collected from various electric loco sheds/ workshops. 5. Presentations given by participants from various Railways during seminar

conducted on 08/10/2004 at IRCAMTECH/ Gwalior.



51

To 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.

OUR OBJIVECTIVE

If you have any suggestions and any specific Comments please write to us. Contact person : Director (Elect.) Postal Address : Indian railways

Centre for Advanced Maintenance technology, Maharajpur, Gwalior. Pin code – 474 020

Phone : 0751 – 2470740

0751 – 2470803 Fax : 0751 - 2470841

railways fo|qr yksdkseksfvo fo|qr yksdkseksfvo dh ddhh dh fgvkph vªsd’ku eksvj...

Documents