Signature

I Page lof16 I Issued on: 01.03.2016 I Report No. RDSO/2016/ELITARl0001 Rev. '0' I

GOVERNMENTOF INDIA

MINISTRYOF RAILWAYS

Technical Audit Report of Electric LocomotiveWorkshop Bhusawal, for maintenance of bearings ofthree' phase locomotive Traction Motors (TM) andMotor Suspension Units (MSU)

Report No.: RDSO/2016/ELlTAR/0001 Rev. '0'

ISsue Date: 01.03.2016

EDSE(Co-Ord)

Approved by

Issued byElectrical Directorate

Research, Designs and Standards OrganisationManak Nagar, Lucknow-226011

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Status of Revision

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SN. Date of Revision Page No. Revision Reason for Revision1. All 0 First Issue

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Technical Audit Report of EL WIBSL

1. Technical audit of ELW/BSL for maintenance of Bearings of three phase locomotivetraction motors and Motor Suspension Unit (MSU) has been carried out from 3.2.2016(AN) to 05.02.2016 (FN). Observations are given in the following paragraphs.

2. Shortage of Critical material: ELW/BSL is facing shortage of several critical materialswhich is also affecting the replacement of 'must change items' during POR. Some of theimportant items which are out of stock are listed below:

SN PLNO Description Out of SectionStockfrom

1 29030031 Set of cylindrical roller bearing for three phase TM 30.5.15 TMtype 6FXA 7059

2 29030020 Set of cylindrical roller bearing for three phase 4.11.15 TMtraction motor type 6FRA6068

3 29018067 Set of Taper Roller Bearing assembly for TM 30.10.15 WHSuspension unit of Hitachi TM HS-15250A.

4 29010020 Cylindrical roller bearing unit CRU-150 (axle box 20.11.15 WH. bearing)5 29030110 Set of cylindrical roller bearing for MSU tube 13.3.15 WH6 29330117 Standard hardware for TM type 6FRA6068 27.3.15 TM7 29940096 Set of labyrinth and bearing cap (DE) for WAG9/ 29.3.15 TM

WAP78 29940060 End frame driving end assembly (machined) of 11.7.15 TM

WAP-7 /WAG-9 loco for TM type 6FRA60689 29940102 Set of labyrinth ring bearing cap & clamp plate 4.12.15 TM

(NDE) for WAP-7 / WAG-9 TM type 6FRA606810 29050066 Set of labyrinth' ring for nose suspended drive (MSU 30.3.15 WH

tube)11 25949690 Set of machined items for TM TAO-659 3.2.15 TM12 29420052 Pinion shaft 21 teeth for WAG-9 20.4.15 TM13 24100055 Set of hex socket head cap screw for tm suspension 16.7.15 WH14 25018050 End Axle Box assembly with plain end cover with 29.4.15 WH

bearing15 25018851 Standard inner races for WAP-1, WAP-4 13.7.15 WH16 25019053 Set of components for axel box of WAP-l and 22.12.15 WH

WAP-417 25018747 Set of axle box bearing components for WAG-7 & 6.8.15 WH

WCAM-3 locos

Above items are vital for proper maintenance of locomotive during POR. Therefore,availability of these items may be ensured.

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3. Bearing Storage3.1 Bearing main storage: Bearings were kept in a dry room, separated from other

components.

Photo 1 & 2: Bearings stored in main store depot

Recommendation: ELW/BSL is advised to keep the bearings little away from wallsto avoid ingress of water/moisture in a stack of not more than 5 bearings. Bearingsshould also not be stored directly on floor. First In First Out (FIFO) system should befollowed to avoid prolonged storage.

3.2 Released Bearing storage in section:Released bearing storage on Shop floor were not proper. Large size MSU bearingswere kept in open condition with dust and dirt. Released bearings which are to bereused should also be stored properly. If bearings are not to be re-used, they should becut by gas cutting. As bearings released from overhauled MSUs (Work order wheels,not due for POR) are reused, proper handling and storage of released bearings isrequired.

Photo 3 to 5: MSU Bearings & components stored at Shop Floor (Not recommended)

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Photo 6 to 7: MSU Bearings & components stored at Shop Floor (Not recommended)

Recommendation:I. Bearing assembly and storage should be done in dust free area. Separate room/dust

free environment should be made available for bearing storage.11. Released bearings should be properly packed and stored in horizontal condition for

reuse. Released bearings should not be stored in stacks of more than 5 bearings. _111. Bearings which are not to be re-used should be segregated and stored separately after

gas cutting.

4 Observations related to Motor Suspension Unit Maintenance:4.1 Greasing: Greasing of bearings is done with bare hands.

Photo 8: Greasing of Bearings with bare hands (Not recommended)

Recommendation: Bearings should be handled with protective industrial gloves.Lint free cloth should be used for cleaning purpose.

4.2 Measurements taken before mounting: ELW/BSL is measuring Drive End & Non-DriveEnd main bore diameter (seating area for Bearings) by two point inside micrometer with leastcount of 1Omicron.Recommendation:(i) It is recommended to check the actual fit dimensions of MSU & assembly components

(mating parts) and axle bearing seating area as specified in paragraph 1.4 of ABB

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document no. AEB 452511 'Drive 15 AN 21 Rl Instructions for Assembly andDisassembly' .

(ii) It is preferable to use 3 point digital inside micrometer with resolution of 1micron.

4.3 Use of Assembly components along with MSU tube in Kit form:At the time of inspection, new assembly components were not available. It was informed thatduring overhauling of the MSU, released components are used in same MSU. It isrecommended that the Suspension tube and its assembly components should be used in kitform and should not be mixed or interchanged. However, the components were not stored inkit form.

Photo 9: Assembly components lying in scattered condition (Not recommended)

Recommendation: It is recommended to store and use assembly components in kit form.One kit should be used for one MSU.

4.4 Availability and use of Torque Wrenches:Torque wrench of 80 Nm & 9.5 Nm are prescribed for use during assembly procedureof MSU. Torque wrench of 80 Nm was defective (dial broken) and Torque wrench of9.5 Nm was not available.Recommendation:(i) Sufficient number of torque wrenches of 80 Nm & 9.5 Nm to be procured and

used during assembly.(ii) It is preferable to use torque wrench with fixed predefined torque. In torque

wrench with adjustable torque, there is a probability that torque may not beset at required value.

(iii) Torque wrenches should be calibrated periodically.

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4.5 Oil bath heating of the bearing racer and assembly components:ELW/BSL is using oil bath heating method for heating of the assembly components forfitment in MSU. Even though, oil bath heating gives uniform heating, it suffers from thedrawback of ingress of dirt/dust/grease etc. in the oil on the components being heated. Oilbath heating is not prescribed by the OEM (Mis ABB). Only induction heating is prescribedin ABB document no. AEB 452 511 'Drive 15 AN 21 Rl Instructions for Assembly andDisassembly.

Photo 10: Heating of assembly components in Oil Bath Heater (Not recommended)

Recommendation:(i) ELW/BSL should procure sufficient number of induction heaters equipped with

essential features like temperature display, temperature hold, auto cut off & de-magnetization.

(ii) Induction heating should always be done in temperature mode as same/similarcomponents of different manufactures may have different properties.

4.6 Measurement of MSU Clearance:Name of Clerance Parameter Measured Bv'C' Clearance Distance between DE labyrinth ring By Feeler gauge

item 2 and Suspension Tube'D' Clearance Distance between inner face of DE side Measured by Scale.

of Suspension tube to the face of main Recommendation:gear To use Go/No Go Gauge

'X' Clearance Distance between NDE labyrinth ring By Feeler gaugeitem 15 and Suspension Tube

'F' Clearance Distance between the NDE labyrinth By Go gaugering item 14 and wheel face

Lateral Play DE side Bv dial gauge

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4.7 Insertion of bearings by hammering:As per prevalent practice, MSU bearing seating area is not heated before insertion ofbearing. Both DE & NDE bearing is inserted by hammering with hammer. Inductionheating is prescribed as per ABB document no. AEB 452511 'Drive 15 AN 21 RlInstructions for Assembly and Disassembly'. LPG flame heating is also permitted in ABBdocument no. AEB 050483, 'Wheel Set assembly procedure'.

Photo n to l3: Insertion of bearing by Hammering with Copper Hammer (Not recommended)

Recommendation:(i) ELW/BSL should procure proper induction heater for heating of the MSU and

follow the procedure given in ABB document no. AEB 452 511 'Drive 15 AN 21R1 Instructions for Assembly and Disassembly'. Induction heating results inuniform heating and it is better than LPG flame heating which produces non-uniform heating and may cause change in properties of the material.

(ii) Insertion of bearing by hammering is not recommended as it may cause dent markson bearings.

4.8 Use of thermoseal compoundELW/BSL is using Fevicol ANR 124 thread locker compound instead ofThermocup 1200 or equivalent prescribed in 'WAG-9 Maintenance and RepairManual Indent Number 3EHW 411416'.

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Photo 14: Fevicol ANR 124 being Used(Not recommended)

Photo 15: Loctite 767(Recommended)

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Recommendation: ELW/BSL should use the Thermocup 1200 or equivalent. CLWis using 'Loctite Anti seize thread compound 767' for similar application which is ahigh temperature anti seize thread compound.

4.9 Flame heating of labyrinth ring item 14 (normally referred as abutment piece)Labyrinth ring ofNDE side (item no. 14) is directly heated by flame heating and inserted byhammering, whereas para 3.13 of ABB document no. AEB 452511 'Drive 15 AN 21 RlInstructions for Assembly and Disassembly' prescribes that, "Heat up the ring item 14inductively to 1000e; and slip it over the wheelset axle until it is stopped by the separatethrust collar. Press it down in this position until it is cooled down".

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Photo 16: Flame heating & hammering oflabyrinth ring (Item 14)

(Improper method)

Photo 17: Arrangement used at CLW for pressing oflabyrinth ring (Item 14) till it cooled down

(Proper method)

Recommendation:(i) ELW/BSL should procure proper induction heater for heating of the MSU

)

assembly components and follow the procedure given in ABB document.(ii) ELWIBSL should follow the instruction of "Press it down in this position until it is

cooled down". Photograph of procedure adopted by CLW is shown in photo 17.

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4.10 Greasing ofNDE side bearing:While providing NDE side bearing in the MSU, approximately 50 gm. Grease is filled byhand. It was informed that for POR wheels, about 200gm grease is filled by hand heldgrease gun. For work order wheels, remaining amount of grease needs to be provided bysheds while using the MSURecommendation:

(i) ELWIBSL should provide complete grease quantity in the NDE side MSUbearings, both in case of POB wheels and work order wheels.

(ii) As per ABB document no. AEB 452 511 'Drive 15 AN 21 Rl Instructions forAssembly and Disassembly', approximately 300 gm grease is required to befilled between rollers of the bearings, about 50 gm grease in the labyrinthreservoir of item number 17 and about 50 gm grease in the labyrinth reservoir ofitem number 15.

(iii) It is advised to provide specified quantity of grease at the bearing fitment stage .only instead of present practice of providing partial quantity initially and partialquantity by manual grease gun.

(iv) Instead of manual grease gun, it is preferable to use grease gun equipped withdigital meter for measuring the grease quantity.

4.11 Fasteners used for MSUReleased Socket head screw bolt (Allen key bolt) ofM12X30 (Property class 8.8) of differentmakes (NORM, FKE, IMAVI, LB etc.) are being used in overhauling of MSU. New boltswere not available. These bolts are not approved by CLW for use in MSU.

Photo 18: Non Standard Socket Head Screw BoltRecommendation:(i) It is advised to follow the instructions issued vide RDSO letter number

EL/2.2.13 dated 12.2.2016 to use socket head screw of approved makes only inMSU of 3-Phase Locomotives/Conventional Locomotives.

(ii) In one MSU tube, only one make of fasteners should be used and mixing shouldnot be done.

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(iii) It is preferable to replace the old fasteners of MSU by new fasteners of approvedmake.

(iv) If released fasteners are of un-approved make, they must be replaced with newfasteners of approved make.

(v) As per CLW Specification No. CLW/MS/3/049 Alt-4, following make of sockethead screw shall only be used in the MSU of WAG-9 Locomotives:(a) Un-Brako (Precision Fasteners)(b) G.K.W(c) Laxmi Precision(d) Sundaram Fasteners (TVS)

The steps of holding bearing race in case of DE bearing and inner bearing ring in case ofNDE bearing till the cool down are not being followed.

4.12 Holding of bearing race (DE) and bearing ring (NDE) during fitmentAs per chapter 2.06 page 26/36 (rev. 12.2001, Indent No. 3EHW-411416) of Maintenance &Repair Manual ofWAG-9 Locomotives for Wheel-set, while assembling DE side bearingfollowing procedure is recommended:"Install the bearing race into the DE of the Suspension Tube seat. The serial number on thebearing race must be facing towards the drive end of the suspension tube. Press the bearingrace up against the stop until the suspension tube has been cooled. The bearing race will sitslightly above the lip of the seat and be correctly positioned later in the procedure"Similarly for NDE bearing also following procedure is recommended on page no. 29-30/36chapter 2.96 page 26/36 (rev.12.2001 ,Indent No. 3EHW-411416)"Heat the inner bearing ring to tore using suitable induction heating equipment. Positionthe inner bearing ring onto the axle shaft until it stops against the labyrinth ring. Press thering against the labyrinth ring and hold until cool. "

Recommendation:The above mentioned procedure should be followed completely as it is critical for properassembling ofMSU. Earlier also, RDSO vide letter number ELl1.3.l0 dated 1.9.2011hadadvised CLWand other workshops to follow the correct procedure.

5 Observations related to 3-phase traction motor bearings:5.1 There was no 3 Phase loco under POR on the date of inspection, hence complete

overhauling of 3 phase traction motor and bearing assembly procedure could not beseen.

5.2 Use of assembly components in kit form: It was informed that ELW/BSL isprocuring and replacing assembly components in the kit form separately for DE &

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NDE side. Released assembly components of 3-ph traction motor were lying on shopfloor.

Photo 19 to 21: TM Assembly components lying on the shop floor

Recommendation:(i) Released assembly components as well as bearings etc. (released from POR

TMs), should be stored after Gas cutting to avoid re-use.(ii) It is recommended to use one kit for one motor assembly.(iii) It was informed that released assembly components are taken by Loco sheds.

Use of released assembly components by Loco sheds is not desirable. RDSOvide letter no. EL/3.2.182 dated 31.7.2007 had advised that assemblycomponents should be replaced in kit form.

5.3 Bearing mounting area: Bearing mounting area needs improvement in terms ofcleanliness. Other activities like component cleaning, air blowing etc. are also donenear the bearing assembly area.Recommendation: Bearing assembly area should be clean and dust free. No otheractivity should be performed near the bearing assembly area. It is recommended toseparate the bearing assembly area from cleaning area. Further scope of improvementto clean the area is still there.

5.4 Heating the bearing inner rings & the End frame: Bearing inner rings are heatedwith the induction heater and the end frames are heated in the heating oven for 3 to 4hours. The induction heater used is Inventurn make, without having the basic facilitieslike temperature display, temperature hold, auto cut off etc. Temperature of the ringsis measured by hand held temperature gun. DE & NDE side inner ring was heated upto 70°C. To heat the end frame inside the oven, the inside temperature of the oven iskept at 150°C.

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Photo 22 & 23: Heating of End Frame in OvenONotrecommended)

Recommendation:(i) ELW should procure sufficient number of induction heaters equipped with

essential features like temperature display, temperature hold, auto cut off & de-magnetization.

(ii) Induction heating should always be done in temperature mode as same/similarcomponents of different manufactures may have different properties.

(iii) Only Calibrated Temperature Guns should be used, ifrequired.(iv) Induction heater shown below can be used for heating end frames. Induction

heating will be fast (l0-15 minutes compared to 3 -4 Hrs in oven) and energyefficient.

Photo 25: Induction Heater for End Frame(Recommended)

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Photo 24: Induction Heater for Racers

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5.5 Marking done by ELW on bearings: ELW/BSL is following the practice of uniquemarking by way of etching on the bearings with the etching ink. Etching is done onbrass cage of TM bearings. It was also informed that etching is also done onpolyamide cage of WAP-5 NDE side bearing. Etching ink is forms by Seleniumpowder, HN03, CUS04 and water.

Recommendation:(i) Laser marking/vibratory pen is preferred for marking on the bearings.(ii) After etching, the component should be cleaned and wiped immediately and rust

preventive oil needs to be applied, if bearing needs to be stored after etching.(iii) Etching should not be done on polyamide cage as well as on rollers.

5.6 Implementation of SMI-278:ELW/BSL is measuring DE end RC as per SMI-278 by using jack and dial gauge,however, ELW/BSL is not carrying out Dye Transfer Test (Colour Matching) and colourmatching of pinion with shaft taper test.

Photo 28: Measurement of Redial Clearance

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Photo 26: Etching by Chemical Etching Ink Photo 27: Etching on cage

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Photo 30: Commutator without end chamfering (Not recommended) •••

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Recommendation:It is advised to follow the SMI-278 completely.

6 Observations related to HS15250 TM6.1 It was observed that balancing weights were welded on commutator disc spring of some

armatures.

Photo 29: Weight welded on disc spring (Not recommended)Recommendation: Balancing weight should not be welded on the disc spring.

6.2 It was observed that Commutator end chamfering is not done by ELW/BSL.

Recommendation: SMI-31 dated 24.10.1978 for 'Undercutting and chamfering ofTraction Motor Commutators' needs to be followed completely.

6.3 It was informed that Becktol Red is used as finishing varnish for Hitachi TM.Recommendation: Becktol Red is E Class (l20°C) Anti-tracking finishing varnish.Prescribed anti-tracking finishing varnish for TAO-659 TM is F-93/RE-118 which is HClass (l80°C). Prescribed finishing varnish for Hitachi TM is TVA-1410 which is Class200°C. Only TVA-1410 varnish to be used as fmishing varnish for Hitachi TM.

6.4 It was informed that Dynamic balancing machine & Surge testing machine were defective.Recommendation: To be repaired at the earliest.

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6.5 Process of Drop test was seen. It is observed that Probe spacing was not proper. Staff was notaware about placement ofthe current & potential probes. Staff counselled regardingsignificance of placement of current & potential probes for measurement of very lowresistance.

Recommendation: SMI-51 dated 30.4.1979 for 'Bar to bar conductor resistance andequaliser resistance test on Traction Motors" needs to be followed properly.

6.6 It was informed that gloves are used for handling the bearings but one pair is used for 15-20days. It is advised to use disposable surgical gloves for handling the bearings.

7 Interaction with officers & Supervisors: At the end of audit, interaction with officers andsupervisors was carried out and the findings of the audit as well as Dos and Don'ts ofbearings were discussed.

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