about my summer training at ac loco shed jhansi 2015

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

2. 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 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

3. CONTENTS
Chapter No. DescriptionPage No.
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

4. 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
4. COMMON FAILURES 43
5. DO’S AND DON’TS 46
5.1 DO’S 46
5.2 DON’TS 47
CHAPTER 1
GENERAL DESCRIPTION
1.1 INTRODUCTION
HITACHI TRACTION MOTOR TYPE HS15250A
Hitachi tractionmotor isone of the mostcritical and vital equipmentinconventional Electrical
locomotivestype WAG-7&WAP-4underproductionat CLW.The productionof Hitachi TM isnow
completelystabilized.

5. (HITACHITM 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 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

6. 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
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)

7. 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
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).

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

9. 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.
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.

10. 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.
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.

11. 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.

13. 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 locomotive Pass./Mail/Exp. Train locomotive
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 and 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.
Inspection & work to be carried out Standard
value
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 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 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

14. 2.3 IB 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
check their conditon
Inspection & work to be carried out
Clean,ok
S.
No.
Inspection & work to be carried out Standard
value
Actual
value
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
7. Check the cables of all traction motors visually for
any
rubbing 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
appearance
for any abnormality.
No
abnormality

15. 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
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, 11.5-13.5mm
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.
Free
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
7. Check the cables of all traction motors visually for any
rubbing 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
appearance
for any abnormality.
No abnormality
2.4 IC SCHEDULE
Carry out the following inspections and fill up the proforma

16. S.
No.
Inspection & work to be carried out Standard value Actual
value
1. Clean inspection covers before removing them and
check their condition.
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
4. 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
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
8.5 Check the flexible leads are firmly secured to the brush
holders.
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
8.9 Check brush holder and positive/ negative lead
insulators for proper glaze and clean them.
Clean
8.1
0
Tight the rocker lock pin and rocker holding bolt. Tighten
8.1
1
Check the bellow net, there should be no foreign
material 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 Actual

17. value
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
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

18. 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.
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.

19. 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.
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
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.

20. 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
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.
Openthe 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

21. 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
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.
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

22. 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.

23. 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.
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

24. 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.

25. Extract the bearing bracket in arrow mark
direction.
Write serial number with white paint to PE
end 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 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-12 2(1set)
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 L-40 -- 2

26. 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(1set)
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 L-40 -- 2
3.5 CLEANING OF ARMATURE BEARINGS
To clean the dismounted armature bearings,
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

27. 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.
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

28. 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.
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 0.1mm 0.03 mm
Inequality in diameter Not more than 0.06 mm 0.006mm
High, 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 –
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

29. 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.
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.

30. 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.
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.

31. 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 HOLDERS
Remove 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 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

32. 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.
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 SHIELDS)
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

33. 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.
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

34. 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.
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.
Description Tool mark Qty.
1. Nut TL-4 4
2. Hook TL-11 5
3. Support disk TL-6
4. Stand TL-19 1

35. 5. Ram with oil power pump -- 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.
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 volt and nut Tightening torque (in .kgf. cm)
Min. value Standard value Max. value
M6 41.0 51.1 61.6

36. 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
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
S.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 Earth brush holder 1 set Earth brush (if required)
13 Grease - Servogem RR-3/ Lithon-3/ Shell
Alvania grease no.3

37. 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

38. 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
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.

39. 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

40. 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
perature. 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).
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 :
I0 - 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.

41. 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.
3.20 INSPECTION AND TESTING PROFORMA FOR OVERHAULING HITACHI
TRACTION MOTOR TYPE HS – 15250A
A- Stage : Pre-inspection
S.
No.
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)
S.
No.
Inspection/ Test Standard value Actual
value
1 Do the baking before and after Done

42. Inspection/ Test
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
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
9 Check top lug thickness 38-40 mm
10 Distance between lug mounting bush and
stator
collar.
16.5-18 mm
Inspection/ Test
11 Check the PE & CE housing e/
shield bore dia
(PE)
(CE
696 + 0.080 mm
+ 0.00
710 + 0.080 mm
+ 0.00

43. 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
4.28-2.68 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
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.
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 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)

44. .
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
D- Stage : Overhauling of Armature & Commutator
S.
No.
Inspection/ Test Standard value Actu
al
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 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 meag 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 200 V 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

45. 13 Check UST of shaft for no flaw. Ok
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
16 i) Radial clearance of free bearing when new.
Pinion end
Commutator end
ii) Actual radial clearance after assly.
Pinion end
0.165 – 0.210
mm
0.155 – 0.195
mm
0.104 –0.177
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
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
S.
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 cracks
4 Check for bedding 90-100%

46. 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 mm
8 Check the ‘k’ value of pinion between
3 teeth for 18 teeth pinion
3 teeth for 16 teeth pinion
4 teeth for 23 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.)
F Stage : Final Assembly
S.
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
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)
CHAPTER 4
DO’S AND DON’TS
4.1 DO’S
1. Add a few drops of mineral oil to the solvent while cleaning the bearings and

47. 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
4.2 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

48. 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).

49. CHAPTER 5
COMMON FAILURES
S.
No.
Failures Possible cause Suggested Remedies
1.
Commuator
Flashed/poor
commutation
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 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.

50. 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 & clean
the 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 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.
3. Overload
relay
tripping due
to
more current
drawn by
traction
motor.
i) Armature winding short
circuited or commutator
segments shorted.
Replace the defective traction motor
and rectify the defect.

51. 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.
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.
4.
Abnormal
noise coming
from traction
motor.
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.
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.
5.
Traction not
effective i.e.
particular
wheel not
rotating.
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.
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.

52. CONCLUSION
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.
NAME-DEEPESH PRATAP SINGH
B.Tech 3rd year
(GLA UNIVERSITY)
MATHURA