White Paper
Reducing the Cost of Locomotive
Traction Motor Overhaul
Process & Procedures
Contents:
• Executive Summary
• Overview
• Overhaul Procedures
• Pre-cleaning
• Final Cleaning
• Vacuum Drying
• Testing & Diagnosis
• Major Cost and Quality Benefits
• Attachments
White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
Executive Summary
During the overhaul of traction motors (TMs) the first and most important operation is the perfect
cleaning and drying of stator and rotor windings prior to testing and diagnosing. Poor cleaning, rinsing
and drying will cause:
•
False diagnostic test readings and will lead to unnecessary rewinding irs operations.
•
Residual dirt and carbon dust on stators and rotors will contaminate varnish tanks.
•
Residual detergent left in windings after cleaning will deteriorate insulation and attract humidity,
all of which will lead to premature motor failures.
The described Cleaning and Drying Technology addresses and resolves these issues completely.
Railways using this Cleaning and Drying
Technology, (see attachment 1 – User
List), have found that out of a random
sample of TMs returned to the shop for
overhaul, only 10% will actually require
rewinding operations, while 90% will
regain acceptable resistance readings
after cleaning and drying and can return
to service after minor repairs and vacuum
pressure impregnation (VPI), (see
attachment 2 – Canadian National
Railway Test Report and attachment 3 –
Norfolk & Southern Railway Test Report).
Regain acceptable
resistance readings
after cleaning,
drying, and minor
repairs
Need rewinding
CLASS-I Railways in US and Canada, using this Cleaning and Drying Technology as part of their overhaul
procedures, expect a service life of 1,000,000 miles between overhauls.
CLASS-I Railways in US and Canada keep their
locomotive fleet running with a traction motor
surplus inventory of 15 - 20% of the installed
number of motors.
The PROCECO Traction Motor Washing & Drying
Plant uses an environmentally friendly, waterbased cleaning process and vacuum drying. This
process is close-looped and conserves the water,
detergent, and energy of the cleaning solutions
for many weeks.
Fig.1: PROCECO 3-stage traction motor washing &
vacuum drying plant widely used in railroad and
OEM TM overhaul shops.
© PROCECO Ltd. 2014
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
Overview
Railways have three choices for the maintenance, repair and overhaul (MRO) of locomotive traction
motors (TMs):
•
Operate their in-house TM MRO-center.
•
Outsource to independent electric motor MRO shops
•
Outsource to the OEMs, the original suppliers of their TMs or locomotives.
In-house TM MROs typically need an annual production requirement of 800-1000 TMs per year to justify
the investment in plant space, state-of-the-art equipment and training necessary to achieve quality
overhauls cost-effectively.
The TMs arriving at a TM MRO originate from three different sources:
1. Scheduled general locomotive overhauls – TMs are likely still in operating condition, but all TMs
will be given a proper clean-up, inspection and minor repairs and part replacements (like bearing
change, commutator turning and undercutting, brushes, etc.) followed most likely by a new coat
of VPI insulation.
2. Scheduled individual TM overhaul after say 1,000,000 miles
3. Un-scheduled, accidented or otherwise defective TMs coming in from the service shops in the
field.
Overhaul Procedures
The following procedures - as practiced by Class I Railroads in the US and Canada - apply – at a minimum –
to all TMs arriving at the MRO-center:
Following these procedures offers the greatest potential saving in the entire TM overhaul activity – the
elimination of unnecessary rewinds! Experience shows that 80 – 90% of motor failures diagnosed in the
field with inferior resistance readings will revert to acceptable readings after passing through the above
process and procedures.
Pre-cleaning
Best practice demands that no TMs move into the TM MRO unless their outside is pre-cleaned as a first
operation. This will maintain the clean environment indispensable for quality TM overhaul work. The
typical equipment to be used for this operation would be a batch-type turntable power spray cabinet
© PROCECO Ltd. 2014
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
washer using a single-stage single chamber water-based cleaning process. (For example: PROCECO Model
HD 75-72-15,000-E(S/G)-SC).
One complete TM is placed on the turntable with its axis horizontal. Depending on the degree of
contamination the cleaning cycle will be 15 –20 minutes. The cleaning process uses a re-circulated heated
cleaning solution made up of water and a low percentage of suitable bio-degradable detergent followed
by a non-recirculated fresh water rinse.
Immediately after pre-cleaning, the TMs are
disassembled and the rotors and stators go into final
cleaning.
The mechanical parts like bearing housings, bearings,
suspension bearing caps, pinions, etc. are placed on a
parts rack and loaded onto the turntable and processed
through the pre-cleaning machine. Parts will flash-dry
due to the heat absorbed during cleaning
Fig. 2: PROCECO pre-cleaning spray cabinet
parts washer with TM components loaded on
part holding rack. TM assemblies can be
placed directly on turntable instead of part
rack.
Final Cleaning
Typical equipment to be used for this operation
would be a batch-type, three-stage, single chamber
turntable power spray cabinet washer using a waterbased cleaning and rinsing process. (For example:
PROCECO Model HD 75-72-15,000-E(S/G)-3-CNP).
One TM stator is loaded onto the turntable with its
axis vertical and in the center of the turntable.
Alternatively four rotors are placed on the periphery
of the turntable with their axis vertical. The cleaning
process uses a re-circulated heated cleaning solution
made up of water and a low percentage of suitable
bio-degradable detergent sprayed at a pressure not
to cause damage to the insulation in the first stage.
© PROCECO Ltd. 2014
Fig. 3: PROCECO spray cabinet washer can clean four
rotors or one stator at a time.
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
This stage is followed by multiple rinses effectively
removing all detergent residues from the windings.
The total cycle time of this process will be 45
minutes plus loading & unloading.
Immediately after the final cleaning is finished,
stators and rotors are transferred into the vacuum
dryer.
Fig. 4: During final cleaning, one TM stator is
positioned in the center of the turntable with its
axis in a vertical position to expose internal and
external surface to power sprays.
Final Cleaning, Typical Results
Before
© PROCECO Ltd. 2014
After
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
Vacuum Drying
Typical equipment for this operation would be a
batch-type heated vacuum chamber of vertical
cylindrical design with hydraulically operated
clamshell lid. TM stators and rotors are transferred
immediately from the washer into the dryer. (For
example: PROCECO Model VD 83-E(S/G). This dryer
can hold two stators or four rotors at a time and will
dry them in 45 – 60 minutes.
Now that all windings have been perfectly cleaned,
rinsed and dried, they must be left to cool down to
ambient temperature before proceeding to testing
and diagnosis.
© PROCECO Ltd. 2014
Fig. 5: TM components are deposited directly on
the vacuum dryer platform. This PROCECO vacuum
dryer model has the capacity to dry one stator or
four rotors per batch.
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
Testing & Diagnosis
Rotors
•
Preliminary resistance Test
Wrap copper braid around commutator and test resistance against armature shaft at 500 V –
DC*
*.
•
Core Lamination Test
Test probes are placed on two opposite ends of armature shaft. Apply power source at 7V – DC
and generate current flow*
*.
•
Bar-to-Bar Surge Test
Test the commutator bar-to-bar for shorts by applying 500V-AC between adjacent bars*
*.
•
High-Potential Test
Test the commutator with high-potential to shaft. Wrap braided copper around the commutator
to short all bars. Apply 4300 V-AC between the commutator and the shaft. Gradually increase the
hi-pot voltages from zero, hold at a specified voltage for one minute and then reduce to zero*.
Note: Never apply hi-pot test until the rotor is at ambient temperature.
Stators
•
Resistance Test
Test resistance of each field coil and interpole coil against frame*
*.
•
High – Potential Test
Apply 2000V-AC between the coils and the frame*.
*Note: Determine acceptable readings with the help and consultation of OEM specifications.
Major Cost and Quality Benefits
The major cost and quality benefits of PROCECO’s Technology are derived from:
1. Elimination of unnecessary rewinding operations.
2. Elimination of premature failures due to detergent residues left in windings.
3. Elimination of contamination of varnish tanks.
4. Extension of traction motor service life to 1,000.000 miles.
5. Reduction of traction motor inventory 15 - 20% of installed inventory.
6. Reduction of time needed for cleaning and drying to 2 hours.
7. Reduction of water consumption due to re-circulation principle.
8. Reduction of detergent consumption due to re-circulation principle.
9. Reduction of energy consumption due to re-circulation principle.
10. Elimination of environmental, health and fire hazards due to water-based technology.
© PROCECO Ltd. 2014
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
Attachment 1 – User List
PROCECO Traction Motor Cleaning Systems Sold Over the Years
Country
Customer
Country
Customer
Australia
State Rail Authority of NSW
Victoria Public Transport Corp.
Pakistan
Pakistan Railways
Panama
Panama Canal Commission
Austria
Austrian Railways (ÖBB)
Poland
Brazil
Cia. Vale do Rio Doce
GEVISA
Polish State Railway
Polish State Railway
Switzerland
SBB/CFF
Tanzania
Tanzanian Railways Corp.
USA
Atchison, Topeka & Santa Fe
Railway
Co.Northern Railroad Co.
Burlington
(2)
Burlington Northern Railroad Co.
MGE
VALE
Bulgaria
Bulgarian Railway
Canada
BC Rail Ltd.
CN North America
CP Rail System
GEC Alstom AMF Transport Inc.
General Electric Co.
Motor Coils Manufacturing Ltd.
Quebec Cartier Mining Co.
Toronto Transit Commission
Egypt
Egyptian Railways
India
Indian Railways
Ireland
Irish Rail
Kazakhstan
Locomotiverem Services Ltd.
Kenya
Kenya Railways
Korea
Korean National Railways
Seoul Metro Subway Corp.
Mexico
CN North America (CNW)
Consolidated Rail Corporation
CSX Transportation Inc.
General Electric Co.
GM Electro-Motive Division
Livingston Rebuild Center
Long Island Rail Road
Motor Coils Manufacturing Co.
Nat'l Railroad Passenger Corp.
(Amtrak)Southern Railway Co.
Norfolk
Rock Island Electric Motor Repair
Southern Pacific Lines
Union Pacific Railroad
VMV Enterprises Inc.
Venezuela
GE Transportation
Electro-Motive Diesel
Total installations: 81
© PROCECO Ltd. 2014
CVG International
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
Attachment 2 – Canadian National Railway Test Report
Traction Motor Armature Preliminary Resistance Test for Diagnostics
Pos.#
Date
Arm.
Make &
Model
Armature
Serial #
Reason for Repair
1
April 04/05
D-87
97D180
Unknown
20kΩ
224MΩ
2
April 04/05
D-87
2499
B/O Commutator
10kΩ
292MΩ
3
April 04/05
D-87
12382
Main Fields Open/Shorted
"0"
890MΩ
4
April 05/05
D-87
99C10630
Overheated
150kΩ
525MΩ
5
April 05/05
D-87
10420
Interpole Open/Shorted
10kΩ
2.7MΩ
6
April 05/05
D-87
73D346
Armature Grounded
"0"
32.6MΩ
7
April 05/05
ARS
21143
Armature Grounded
10kΩ
510MΩ
8
April 05/05
D-90
38219
Shifted Interpole
30kΩ
248MΩ
9
April 06/05
D-87
4426-1-95
Armature Grounded
30kΩ
312MΩ
10
April 06/05
ARS
21171
Burnt Brushgear Cable
20kΩ
915MΩ
11
April 06/05
ARS
39104
Armature Grounded
20kΩ
650MΩ
12
April 06/05
ARS
21280
Armature Grounded
"0"
332MΩ
13
April 06/05
D-90
38060
Armature Grounded
"0"
466MΩ
14
April 06/05
D-90
41959
Flashed Commutator
"0"
595MΩ
15
April 07/05
D-90
38745
Noisy Bearing
820kΩ
520MΩ
16
April 07/05
D-90
36789
Main Fields Open/Shorted
110kΩ
585MΩ
17
April 07/05
D-90
40030
Armature Grounded
20kΩ
466MΩ
18
April 07/05
ARS
20946
B/O Pinion
10kΩ
272MΩ
19
April 07/05
D-87
98C8691
Overheating
20kΩ
372MΩ
20
April 07/05
ARS
25810
Unknown
90kΩ
1.04GΩ
Source: Canadian National Railway, Transcona Shops, Winnipeg, MB, Canada
Biddle Test
@ 500V
Before Clean
& Dry
Biddle Test
@ 5000V
After Clean
& Dry
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White Paper
Reducing the Cost of Locomotive Traction Motor Overhaul
Attachment 3 – Norfolk & Southern Railway Test Report
Traction Motor Armature Preliminary Resistance Test for Diagnostics
1000 Volt Megger
Test (MΩ)
Before
After
Cleaning
Cleaning
Cleaning
& Vac.
& Vac.
Drying
Drying
21.6
500
Pos.#
Date
Frame
Serial #
Armature
Model #
Armature
Serial #
Reason for Repair
1
4/1/2005
89h12067
D87BTR
mc00F8422
Armature Grounded
2
4/1/2005
94j12055
D90
94f99
Motor change-out
132
200
3
4/1/2005
ee98040990
AH
ee98041054
Armature Grounded
1.3
2000
4
3/31/2005
41573376
AG
60479555
Brusholder broken
72.2
2000
5
3/31/2005
47b1409
D77
a30863
Motor change-out
111
400
6
3/31/2005
ee00112100
AH
ee00124137
Armature Grounded
1.8
300
7
3/31/2005
gemye0005
D77
mc93h5035
Motor change-out
158
400
8
3/30/2005
89e12093
D87B
95a34264
Slipped pinion
6
237
9
3/30/2005
e92060055
AH
20879852
Slipped pinion
250
500
10
3/30/2005
e92080404
AH
80301071
Lead damage
47.2
2000
11
3/30/2005
ee97102124
AH
ee97115133
Armature Grounded
1
400
12
3/30/2005
ee99030946
AH
ee98026815
Slipped pinion
162
500
13
3/29/2005
01ecn203
D78
mc90h7271
Motor change-out
238
1000
14
3/29/2005
8910671
AG
97k93092919
Derailed
19
ovr
15
3/29/2005
91h12055
D87BTR
mc98a2205
Motor change-out
77
500
16
3/29/2005
91j12061
D87BTR
my2001b031
Motor change-out
172
188
17
3/29/2005
93j1440v
D77
1368
Motor change-out
ovr
500
18
3/29/2005
ee98020490
AH
ee98041069
Motor change-out
67
500
19
3/29/2005
ee99020693
AH
ee99038542
Motor change-out
74
1000
20
3/29/2005
mye0261
D87B
85h1890
Motor change-out
14
ovr
Source: Norfolk & Southern Railway, Juniata Shops, Altoona, PA, United States
PROCECO Ltd
7300 Tellier Street
Montreal, QC H1N 3T7
Canada
cleaning@proceco.com
Tel.: +1 514 254-8494
www.proceco.com
© PROCECO Ltd. 2014
November 2014
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