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qiifi-qvqd Telephone | 0522-24657 73 Fax: 91-0522-2452587

No. ELl3.2.17612 Date: 15.03.2018

Chief Electrical Engineers,

r Central Railway, Mumbai CST- 400 001.

r East Centre Railway. Hazipur, Bihar - 844 101.
. East Coast Railway. Chandrashekharpur. Bhubaneshwar-751 016.
. Eastern Railway, Fairlie Place, Kolkata- 700 001.
. North Central Railway, Sr,rbedarganj. Allahabad-211 033.
. Northern Railway. Baroda House. New Delhi- 1 I 0 001 .
. South Central Railway.Rail Nilayam. Secunderabad- 500 071.
. South East Centre Railway. Bilaspur-495 004.
. South Eastern Railway. Garden Reach, Kolkata- 700 043.
. Southern Railwa,v, Park Tow-n, Chennai-600 003.
r West Central Railway, Jabalpur- 482 001.
r Western Railway. Churchgate. Murnbai-400 020.
. Chittaranjan Locomotive Works. Chittaranjan-713 331.
. Norlh Eastern Railway,Gorakhpur-273012.
. Norlh Western Railway,Jaipur-302006.
. North East Frontier Railway,Guwhati-781 012
. South Western Railu,ay.Hubli-580031.

SPECIAL MAINTENANCE INSTRUCTION NO. RDSO IZOISIELISMI/O319

(REV.'0'), Dated 15.03.2018

1. Title:

Special Maintenance Instruction for maintenance of Oil Cooling Unit (OCU) for
3- phase Electric Locomotives.

2. Brief History:

In absence of any guidelines for maintenance of OCB, Zonal Railways are

following different practices for its maintenance which creates problems for
reliability. Railways have requested RDSO to issue guidelines for maintenance of
OCB so that proper & uniform maintenance practices can be implemented.
Therefore, detailed procedures for maintenance of OCB ale chalked out & issued
in this Special Maintenance Instruction(SMI).

3. Object:
To provide Maintenance Instruction for Oil Cooling Unit (OCU) for 3- phase
Electric Locomotives.

Page I of7
4. Activities to be undertaken on Oil Cooling Unit (OCU) during different schedules

4.1 IA & IB Schedule

a) Check for abnormal noise. vibration level of OCU casing, burning smell.
b) Check for looseness and crack of motor mounting .

c) Check and tighten the foundation bolts of OCU .

d) Check and tighten the tenninal connections.

e) Check the condition of terminal lugs.
0 Check the impeller blades, casing etc. for cracks" looseness etc.
g) Check the earthing connections of the motor body.
h) Check OCB casing fixing bolts with radiator.

4.2 IC Schedule

In addition to the works in IA /IB schedule, following additional works to be

carried out during iC schedule.

a) Dust accumulated inside walls of OCB casing/motor/Impeller should be

cleaned with brush keeping a protective cover on radiator. Then after , blow
dust with compressed air.
b) Ensure intactness of duct jointing felt, tightness of foundation bolts.
c) Check the bearing condition using Shock Pulse Meter (SPM).Where
bearings are found to be giving abnormal vibrations and noise by SPM, the
clearance of the bearings to be measured and balancing of impellers to be
checked/done as per need.
d) Lubricate motor bearing by approved grease.
e) Check OCU round gasket/casing inspection cover gasket for air leakage and
if any leakage found , RTV should be applied to arrest the air leakage.

4.3 Term Over haul (TOH) Schedule

All the works mentioned under IA, IB or IC to be done in TOH also. in addition
to this, following activities are to be carried out in TOH.

4.3.1 Pre -Testing

a) Check the insulation resistance of motor winding with the help of megger.
b) Give three-phase supply and start motor to check starting and running current.
c) Check and note down the defects and abnormalitl, if any.
d) Check the impeller with Red Dye Penetrate Test (RDPT) or Magnaflux test
for detecting any crack/discontinuity in the surface or w.elded portion.

4.3.2 Dismantling

a) Remove the impeller with the help of puller.

b) Unscrew the bearing cover bolts on both sides.

Page2 of 7
 c) Unscrew the end shield bolts and remove end shield , check the condition of
end shield, grease cups! .

d) Take out the rotor from stator carefully cover overhang porlion with nomex
paper, take out rotor cautiouslv without damaging the winding.

4.3.3 Cleaning

a) Clean duct, impeller and cover.

b) clean the motor parts i.e. stator, rotor, bearing, grease cup (both outside
and inside), end cover, protection by kerosene oil.
c) Dust accumulated inside walls of OCB casing/rnotor/Impeller should be
cleaned with brush keeping a protective cover on radiator. glo* dust with
compressed air.

4.3.4 Overhauling of stator

a) Dry statol by keeping in the oven.

b) check the condition of terminal box/rugs and replace if required.
c) Surge test is done as per SMI/|49.

4.3.s Overhauling of Rotor.

a) Remove the bearing with bearing puller.

b) Check the rotor bars crack by growler test.
c) Check the bearing seat area of the rotor shaft.
d) check the key slot o, shaft and co,ditio, of the impeller key.

4.3.6 Impeller

By DPT check for any cracks o, Impeller, if found any defect replace
impeller.

4.3.7 Assembly

a) As per SMV79 befbre providing new bearing to be checked and tested for
any abnorrnality.
b) Ensure fits and limits on bearing as per SMVI6.
c) Measure bearing clearance of free bearing as per SMy23.
d) Provide the new bearing on rotor shaft, after heating it upto 70-g0oc with
induction heater and lock the bearing w.ith circlips. Bearing to be filled
with servogem-3 or its Equivalent grease.
e) Replace the bearing every overhauling i.e l8 months for wApT and 24
months for WAGS .
0 Inserl the rotor carefully in stator covering winding overhang porlion with
nomex paper.
g) Bearing retainer ANR 124 should be applied slightly before fixing end
shield on bearings.
h) Mount the end shields and tightent the end shield and grease cup bolts.
Replace and shields if found slack on stator.
Page 3 of7
 i) Ensure the free rotatiotl of rotor.
i) Fit the impeller on the shaft and lock with locking plate as per tire
procedure mentioned in 4.6.
k) Check the stator resistance, IR values
1) Check the fitting of nuts and bolt screws.
m) Check the vibration level on OCU casing .
n) Check for moister contents/rvater ingress in terminal box and at cable
casing. If any symptoms of moister contents/u'ater ingress are observed,
then apply RTV on terminal box cover and casing cable termination to
avoid same.
o) Check OCB round gasket/casing inspection cover gasket for air leakage
and if any leakage found , RTV should be applied to arrest the same.
p) Replacement of 10 sq mm cable t,vpe 4GKW-AX of cooling unit by 16sq
m; ( from motor terminals to duct junction box) as per RDSO MS no:
39s.
q) Check the condition of knurling washers/gasket between OCB casing&
radiator .If required replace it.
r) Ensure provision of Epoxy molded terminal box cover as per RDSO MS
no: 290 Rev'1'.

4.3.8 Testing

a) Carry 1o load test on moto1 to measure no load current and decibel of

bearing.
b) Carry load test w.ith irnpeller fitted on motor shaft. the motor should not
exceed rated current of motor.
c) Check OCB round gasket and change if required.
d) Measurements to be recorded during OCB (Overhauling( Enclosed as
annexure)

4.4 IOH & POH Schedule

4.4.1 A11 the w-orks mentioned in TOH schedule shall be carried out in IOH also.
Addition are as under:

a) Bearing replacement of tnotor.

b) Check the rotor bar crack with growler test.
c) Impregnation of stator as per SMI no: 86.

5. Assembly procedure of impeller on motor shaft

5.1 Before fitting of impeller on the motol shaft following checks must be done.

1 of Hub with a "Go or no-go gauge" must be checked'

. Bore
2. Keyway width should be checked as follou's:

a) Take out key of motor and push into keyway of hub and ensure that it
goes freely.
b) File keyway of hub if it does not move.
Page 4 of7
 c) Key should not loose in the keyway.
d) If key is loose, another neu,key to be used.
e) Check keyway depth with the help of Vernier Caliper.
0 Place the key properly in keywal,of motor.
g) Check H and H1 dimensions.
h) Maintain Hl - H:0.05 to 0.1 mm. as shown below

I
I
I
i

SHATT I Iirtl ll()trt:

After carrl,ing out above checks, the impeller should be press on the motor shafi
with proper press equipment. Special equipment jack/ pusher or puller should be
used to push in and pull out the impeller.

5.2 Follovr'ing imporlant precautions should be taken while assembling the impeller
on motor shalt.

a) Never exeft force on any other parl of the impeller except hub/ boss for
pulling out or pushing in the impeller.
b) Do not use hammer for pushing in the impeller.
c) Never try' to pull out impeller by holding shroud with a puller. This can
damage the impeller to unrepairable extent. Shroud may deform or a
prestress will be developed u,hich can cause failure in service.
d) Sometimes motor footings are broken or outlet flange damaged due to
mis-handling. Plane difference of motor and outlet flange causes
assembled uuit to rest on edge of outlet flange of casing and rear part of
the motor foot which sometime results in "Broken motor foot" or outlet
flanged twisted/ damaged/ welding crack. To avoid this, blower motor
assembly may be fitted on a dummy wooden stool, which shall be
removed only at the time of fitment in the loco. Assembled unit should not
be kept on floor without stool.

5.3 Dynamic balancing of impeller with motor during replacement of

impeller

As per TC No. RDSO/2013lELlTCl0123, Rev'0', the impeller should be

replaced in every POH. Dr,u'ing schedule maintenance of Impeller, if crack is
observed on Impeller, it should be replaced by neu,one with matching pair of

Page 5 of7
 cone ( matching pair means the impeller & cone should be of same make)
and local welding of impeller should not be done . Fufther, every impeller
shall be dynarnic balanced to G2.5 grade as per ISO - 1940 .

5.4 Special Precautions to be observed during maintenance of OCB & its

motor
a) Do replace bearings of OCB in TOH.
b) Do balancing of impeller during POH as well as after repairs.
c) Do ensure 100 % replacement of bearings during IOH/POH.
d) Do ensure availability of special tools in section required for repairing/
overhauling.
e) Do use puller and pusher for removing and fitment of impeller.
0 Do ensure winding diagram and winding procedure for rewinding work
being done through trades.
g) Do change the impeller if it is unbalanced due to vibration etc.
h) Do ensure use of approved winding wire and procurement from approved
sources only as per rewinding specifications.
i) Do use approved make of varnishes, leads and sleeves,
j) Do pretest the locomotive before taking into schedule.
k) Do change the cracked motor end shield.
1) Do depute tu'o persons for removing and assembling of OCB rotor to
avoid damages at overhang porlion due to falling by weight.
m) Do ensure proper identification mark on the rotors fitted with bearing
numbers 6312 to avoid interchanging during assembling.
n) Do vacuum pressure impregnation of stators.
o) Do surge test on stator after every overhaul.
p) Do dye penetrate test/ magna flux test for crack detection.
q) Do measure shaft dimensions at bearing seating as per norms.
r) Do prevent stretching of supply leads.
6.0 LIST OF SMIiLETTER / SPECIFICATION FOR IMPROVING
RELIABILITY OF OCB UNIT.

SN TITLE SMI/Letter no: reference

I Reu,inding materials for Auxiliarv RDSO/ELRSiSMIi 1 85-2000 Rev. 1

motors and Arno Converters.

,,
Use of corona resistant wire for RDSO letter no: ELlz.2.8l17 dated
manufacturer and rewinding of auxilialy 1410812008 & amendment no; to
motor of three phase Locos RDSO specification no: E 10-3-09
(motor)

7.0 TEST FACILITIES

The following minimum essential testing facilities are required for blowers:
a) Manometers
b) Control panel comprising wattrneter, ammeters, voltmeters, frequency
meter etc.
c) Multimeter
Page 6 of7
 d) Tongue Tester
e) Tachometer
0 Vibration meter
g) Shock pulse meter
h) Stop watch
i) Thermometers
j) Air velocity meter
k) Vernier calipers, screw gauge, scale, etc.
1) Megger.
m) Magna flux meter.
n) Surge tester.
o) Induction heater for.heating bearing.
p) Grease gun.
q) Puller of various types for removal of bearing and impeller
8.0 Application to the Class of Locomotives:

Oil Cooling Blower (OCB fitted in 3-phase locomotives viz. WAp5, WApT
and
WAG9/WAG9H.

9.0 Agency of Implementation:

All Electric LocoSheds holding 3-phase Electric Locomotives and poH shops
carrying out POH of 3-phase Electric Locomotives.

10.0 Periodicity oflmplementation:

Minor schedule inspection (IAIIB/IC), ToH/MoH, IoH and poH schedules

and
any other unscheduled maintenance as per need.

(A.K.Shukla)
Encl: Nil for Director General Std./Elect.

copy to: As per sta,dard Mailing List No.EL -M-4.2.3-|9(latest revision)

i1,.
-
,o;iffii.B,*
Encl: Nil for Director General Std./Elect.

Page 7 of7
 ANNEXURE

n RE,COMMENDED VALUE OBSERVATION

PARAMETER
1) Stator IR value Above 5 mesa Uhm
2) Surge test on 5kV Good Wave torm
3) Condition ol lugs & Visual Examtnatton
terminal block
4) Condition of end shields & Visual Examination
grease cups
s) No load voltages & current Record the current
( with out imPeller)
6) Voltages & current Current drawn should not
( with impeller) exceed rated current
t) Starting time to achieve full Not more than 6 sec
speed with imPeller
8) SPM reading GREEN ZONE
e) Impeller sl no & make & Record
record
10) DPT test on imPeller