M.t.

3317-7
*Rev. E

AR-TYPE TRACTION ALTERNATORS

“2. _. - ~. _i

DESCRIPTION Current production models are equipped with an air -

box cover which includes diode viewing windows
The purpose of this maintenance instruction is to and two access doors, Fig. i. These doors provide
supply maintenance information for the AR-type easy access to the collector rings or brushes for
traction alternator portion of a main generator. The inspection or replacement of brushes. Another
main generator consists of an AR-type traction feature is the collector ring cover, Fig. 2, to prevent
alternator and a D14 or D18 companion alternator. snow from entering the collector ring area.
The D 14 or D 18 companion alternator is physically
comrected to, but electrically independent of the
traction alternator.

Differences between AR-type traction alternator

models wiil be identified throughout this mainte-
nance instruction, but this instruction will apply to
all models unless specifically identified.

The main generator consists of two, three-phase,

alternating current generators with a single bearing.
‘The spiders of the two machines are bolted together
and the coupling disc of the companion alternator is
boited to the coupling of the engine, the outboard
end of the traction alternator rotor is supported by a
bearing.

The rotating fields of the traction alternator consist

of series connected field coils wound on laminated
poles, which are bolted to a drum-type spider. The
spider is connected to the rotor shaft which is 28916
supported by the bearing mounted in the main
generator end housing. Fig.1 - Typical Main Generator

The field coils are insulated with class “F” The traction alternator stator frame and core
insulation, and are electrically connected to the two assembly, utilizing welded construction, provides a
inboard collector rings mounted in the air box at the rigid structure which houses the stator windings and
bearing end of the assembly. The D14 or D18 supports the end housing and D14 or D18 stator
companion alternator field coils are electrically assemblies. The class “H” insulated traction
connected to the two outboard collector rings. The alternator stator coils are internally connected at the
collector rings and associated brush holders provide bearing end of the stator into two sets of three-phase
the means of exciting the fields of the two machines. “Y” connected windings.

*Extensively revised and completely retyped. Supersedes previous issues of this number.

DE-L385
 M.I. 3317-l

CLEANING
Both the interior and exterior of the traction
alternator should be kept clean and free of dust, dirt,
oil, and water which are likely to have a detrimental
effect on insulation and performance.

As often as conditions warrant, the alternator

should be blown out with low pressure air. Avoid
excessive air pressure which could cause damage to
insulation.

Clean bound-edge, lintless wiping cloths should be

used as necessary to remove oil, grease, and
accumulations of dirt. It is essential that the rectifier
section be kept as clean as possible at all times.

COLLECTOR RINGS AND

BRUSHES
Collector rings and brushes, Fig. 3, should be
frequently checked for sparking while the generator
is in operation. If the collector rings are sparking,
refer to Collector Ring Sparking section for causes
NOTE and repair.
Model AR1 1 traction alternator has a two piece collector ring cover.

28576

Fig.2 - Brush Holder Installation

‘Iwo rectifier assemblies mounted on the front of the
main generator provide means of converting the
three-phase AC power to DC power. Each assembly
consists of high-current, high-voltage, silicon diodes
connected in a three-phase, full wave, rectifier
circuit, and mounted on heat sinks capable of
providing adequate cooling.

For information on the ARIO, AK12, AR15, and

AR16-D14 or D18 rectifier banks, refer to
M.l. 33 17-2. For information on the AR1 1 rectifier
banks, refer to M.I. 3317-3.

For information on the D14 alternator, refer to

M.I. 3306. For information on the D18 alternator,
refer to M.I. 3307.

MAINTENANCE
The traction alternator is designed and manu-
factured to provide a long service life and optimum
performance with a minimum of maintenance. Like
any machine, however, certain maintenance is
required, the extent of which is largely determined
by the operation and service to which the alternator 28577
is subjected. Inspections and maintenance should be
performed at the time intervals as specified in the
Scheduled Maintenance Program. Fig.3 - Collector Ring And Brush Arrangement

-2-

_I-..__-.-..- --.- I_ -..-- -

__.,--.-_
 MJ. 3317-i

It is norma! for the negative collector ring !o wear The above coliditions can usual!y be corrected by
more rapidly than the positive rinp. The unequal grinding. However, the minimum acceptable
wear can be minimized by reversing polarity of the diameter of collector rings is 260 mm (10-t /4”). If
rings every six months. Refer to Service Data for rings cannot be cleaned up without going below
condemning limits of the collector rings and minimum diameter, they shouid be renewed. Rings
brushes. should also be renewed if lateral runout exceeds
0.8 mm (l/32”).
COLLECVOR RING SPARKING
A collector ring grinder is available (8219264) which
Sparking on collector rings should be corrected must be mounted to the generator with an adapter.
immediately to prevent failure of the generator. Adapter 9504268 is used on large bearing (260 mm)
generators and adapter 8364940 is used on smail
The various causes of sparking and their remedies bearing (215 mm) generators.
follow.

O I L O N S U R F A C E O F C O L L E C T O R RiNG
Use..the following procedure to grind the collectoi
If collector ring surfaces are oily, wipe off the ring surface.
surface of the rings and brushes with a clean, dry,
lintiess cloth. C.&w-t3PJ
Never use emery cioth to polish coiiector rings
BRUSH HOLDER LOOSE or to sand new brushes.

The generator is equipped with eight constant I, Remove the collector ring cover (snow guard),
pressure brush holders, four rnounted at the top of the four 12 o’clock brush holders, and remove
the collector ring assembly, and four at the bottom. diode fuses as required to provide clearance for
If a brush ho!der is not mounted securely to the the grinder and adapter. If b!ushes are to bc
brush holder stud or the stud itself is loose, it will reinstalled, labe! them so that they may be
allow the brushes to bounce on and offthe collector reinstalled in their original positions.
ring, resulting in sparking. Tighten all mounting
bolts. 2. Mount applicabie adapter assembiy ai the
2 o’ci0ck position on the beariilg housing rla:ige
DAMAGEi BRUSH HOLDER using two of the cigh; 3/4”-10 bearing housiztg
bolts.
Make certain that brushes are free to move up and
down in their slots. The spring pressure, on constant
pressure brush holders, is preset and cannot be Use care to avoid damage or loss of ths
adjusted. The pressure will remain constant insulating washers or Insulating strip, a:;6 bolt
throughout the brush life, regardless of brush wear. hole insulated tubes surrounding the bearing
Refer to Service Data for spring pressure value. housing to end housing bolts so tizat ciectricai
iso!ation of the bearir;g is maintained.
Check that each brush is cen:ered to within 1.6 mm
(1,’ 16”) of the mating collector ring, when facing the 3 . Mount coliector ring grinder to grinder adapter.
brush holders. The right-hand side of ail brush
holders is set closer to the collector rings than the 4. Position grinder so that there is 3 mm (l/S”;>
left side. Check that the right-hand side is I .6 mm f clearance between the grirlder icnd the collector
0.8 mm (l/ 16” 111 l/32”) closer. ring to be ground. -

ECCENTRIC OR PIT-I-ED COLLECTOR RINGS 5. instali grinding stones in position on grinder.

Ensure there is eriough travel to grind the rings.
If collector riilg eccentricit:! exceeds 0.15 mm
(0.006”) total inditator rt:ad;ng (ring assembly cAuPIaN
installed) the ring wit1 have 10 be machined to bring Make certain that grinding stories do ~:ot
it into tolerance. A rough or pitted coiiector ring CGiltriCt collector ring surface until genernior
surface should also be cleaned up by machining. begins rotating.
M.I. 3217-I
1. Contamination of grease.
6. Make necessary preparations to start engine.
Start engine and run it at approximately
600 RPM. 2. Excessive thrust due to misalignment.

3. Pounding caused by worn rollers of bearing

7. Gradually bring stones in contact with ring
surface. Grind ring surface until it is smooth. being !oose on shaft.
After grinding, stop engine and recheck
eccentricity with a dial indicator. 4. Actual bearing failure caused by bearing fatigue
or wear.
8. When grinding operation is complete, stop Model AR10 generators manufactured prior to
engine and remove grinding equipment. Blow November, 197 1, were equipped with a 215.00 i mm
all grinding dust from stator and rotor (8.4646”) bearing with a phenolic lined bearing
assembiics. Use high volume low pressure air. housing. Model AR10 generators manufactured
after November, l971, and all the other models
covered in this maintenance instruction, have a
Current model generators are equipped with 259.999 mm (10.2362”) bearing.
eight constant pressure brush holders, fo:rr
mounted at the top of the collector ring The large bearing will operate for a longer service
assembly, and four at the bottom. Earlier period than the smaller bearing and will require
model generators had four double arm brush maintenance at intervals rt-commended in the
holders mounted at the top of the collector ring Scheduled Maintenance Program. The small
assembly. The brushes riding on the two inside bearing should riot require maintenance, but should
collector rings are for the main generator, and be replaced with a new bearing and bearing housing
the brushes riding on the two outside collector at intervals recommended in the Scheduled
rings arc for the companion alternator. The Maintenance Program.
spring pressure is preset and cannot be
adjusted. The pressure will remain constant
throughout the brush life, regardless of brush
wear. The 1r:rge (259.999 mm [10.2362”]) bearing requires
maintenance at intervals rt;ommended in the
9. Reassemble brush holder assemblies in their Scheduled Maintenance Program. This can be
proper positions. Renew brushes if necessary, accomplished either by removing the main generator
refer to Brush Renen,al. from the instailation and following the Generator
Disassembly procedure of this instruction or by
maintaining the bearing with the generator in place
as follows:
When installing new brushes, they should be sanded
to fit the curvature of the collector ring. This can be 1 . Remove the two center sections of the air box
done by placing a piece of sandpaper on surface of assembly.
ring with rough side against brush. Then with the
brush held down by brush holder spring tension, 2. Disconnect collector ring brush ilolder connec-
mcve sandpaper in direction of normal rotation of tions and tape leads away from work area.
ro:or shaft until brush conforms to ring surface.
3. Remove tgp and bottom brush holders from
9EA mounting studs.

A sealed, grease lubricated, self-aligning bearing is 4. Disconnect field leads from collector ring studs,
assembled into an insillated housing. The bearing Fig. 4 or 5 as applicable.
housing is insulated to prevent damage from
electrical arcing. No additional lubrication, other 5. Remove the four bolts securing the retainer
than recommendations in the Scheduled Mainte- plate, Fig. 4 or 5 as applicable, to the end of the
nance Program. is required. Occasional checks of shaft and remove retainer plate.
bcaring temperature during operation will give an
indicr~tion of bearing condition. Obtain temperature NOTE
readings by applying a pyrometer to the outside Al! puller tools used to remove the collector
surface of the bearing cover. Bearing temperature ring assembly and Giiter seal may be fabricated
shou!d not exceed a 25” C (45O ??j rk. I-figh bearing as detailed in File Drawings listed in Service
temperature may be caused by: Data.
 M.I. 3317-l

Bearing Hydraulic Collector Ring Puller Stud Location For

Cover Pump Assembly Removing Collector Ring
Connection Assembly
\ Puller \ I

Puller Stud L&cation

Plate - For Removing Outer
S e a l / ,
::~eLead~

Grommet
Jack Assembly Oute; Seal 4
f i
Puller Plate Bearing Cover
28580

Fig.6 - Collector Ring And Outer

Fig.4 - AR1 1 And AR1 6 Collector Ring Assembly Bearing Seal Removal

Brush Bearing 7 . Install puller plate and puller studs to remove

Holder Cover collector ring assembly, as shown in Fig. 6.
Place jack assembly between the extension cup
- -- and the puller plate. supported by cradle stud&
of the puller plate. Connect hydraulic pump to
jack assembly. Ensure puller is pulling equally
on all studs to prevent damage to coilector ring.
Apply hydraulic pressure to jack assembly to
remove collector ring assembly.

8 . Remove puller studs from col!ector ring

assembly.

9 . Install puller plate and puller studs to remove

outer seal, as shown in Fig. 6; Place jack
assembly between extension cup and puller
plate, supported by cradle studs of the puller
plate. Connect hydraulic pump to jack assem-
bly. Ensure puller is pulling equally on all studs
28579 to prevent damage to outer seal. Apply
hydraulic pressure to jack assembly to remove
Fig.5 - AR6, AR1 0, AR1 2, AR1 5 outer seal. Remove jack assembly, hydraulic
Collector Ring Assembly pump, puller plate, and puller studs.

1 0 . Remove bolts from bearing cover, Figs. 4 or 5,

6. Remove four 3/S”-16 bolts securing, the and remove cover. If cover is stuck to bearing
collector rings to the collector ring hub. The housing, hit outer periphery of cover with a
bolts are located on the coiiector ring face rawhide mallet or similar tool to loosen.
between the lead connection terminals, Fig. 3.
Place extension cup around field leads and bolt Il. Inspect grease in the bearing cover and inspect
cup to shaft as shown in Fig. 6 . exposed side of- the bearing. Look for metal
M.I. 3317-l

particles in the grease, excessive wear in the 17. Remove old grease from exposed side of
housing of the bearing; fatigue damage on the bearing and as much as possible from between
rollers or roller path, or evidence of overheating. the rollers and cage. Use only a putty knife and
Replace bearing with a new bearing, if required, fingers. Do not use a solvent. Be careful not to
and replace any associated parts found in introduce dirt or any other foreign substance
distress. into the bearing. Repack all spaces on the
exposed side of the bearing with grease. If Shell
12. If no distress is found, thoroughly clean the Cyprina grease is present in the bearing, Esso
bearing cover. Unirex N-2 grease may be added.

13. Fill the labyrinth grooves in the bearing cover 18. Install the greased bearing cover with new
with Esso Unirex N-2 grease. This grease need gasket. Ensure the space free of grease is at the
not be measured. top of the cover. Tighten bearing cover bolts to
68-75 N-m (50-55 ft-lbs).
14. Weigh the piece of paper that will be used in
handling the grease to fill the groove in bearing CAUTION
cover. The weight of the paper must be In Step 19, do not allow seal to be heated above
compensated for when weighing the grease. 105” C (220’ F). Overheating may result in
warping or damaging the metal.
1.5. Carefully weigh the Esso Unirex N-2 grease for
the bearing cover gioove. Refer to Service Data 1 9 . Heat the outer seal in an oil bath, electric oven,
for proper quantity. or induction heater for half an hour at 105” C
(220” F). If an oil bath is used for heating,
NOTE remove oil from seal with clean, bound-edge
Adequate lubrication depends upon precise cloths prior to shrinking to the shaft. When
weight of grease. Too much grease is as using an induction heater, pyrometer readings
detrimental to the service life of the bearing as (with current off) should be taken periodically.
too little. After heating, shrink the seal to the shaft and
allow it to cool to room temperature.
16. Pack grease into bearing cover groove: Leave a
space free of grease at the top of the bearing 20. Place collector ring on induction heater and
cover to limit churning and liquefaction of the heat to 105” C (220” F). Pyrometer readings
grease. Form grease to proper contour as (with current off) should be taken periodically.
shown in Fig. 7. After heating, place collector ring against outer

Grooves Flush

Weighed Grease

25.4 mm f 1.5 mm

9.5mm 3~ 1.5mm
- (3/W + l/l G”)

28581

Fig.7 - Application Of Grease To Bearing Cover

-6-
 .M.I. 3317-i

seal. Rotate ring assembly on shaft for proper BEARING CHANGEOUT

position of lead connections to terminals of ring
assembly. NOTE
Early Model AR10 traction alternators having
WARNiNG the small bearing, require bearing replacement
If work involving collector ring connections at intervals recommended in the Scheduled
has been performed, use a continuity tester Maintenance Program.
(with all field leads disconnected and all
brushes lifted) to check that collector ring Current traction alternators having the large
terminals marked 1 through 4 on the steel bearing, require bearing replacement when
housing adjacent to the terminals are con- inspection has determined that the bearing is
nected to t,he appropriate collector rings (No. 1 defective or at intervals recommended in the
outboard, No. 4 inboard). Scheduled Maintenance Program.

21. Place retainer plate over leads and on to the end The following procedure is applicable to both,
of the rotor shaft. Tighten 5/8”-I 1 bolts to 135.5 the current large bearing traction alternators
to 149 N-m (100-l 10 ft-lbs). and the early Model AR10 traction alternators
with the small bearing. ,.
22. Connect the large leads from the traction
alternator to collector ring terminals 3 and 4, The traction alternator bearing can be changed out
and the smaller leads from the companion either by removing the alternator from the install-
alternator to terminals 1 and 2. Torque to 9.5 to ation and following the Generator Disassembly
12.2 N*m (7 to 9 ft-lbs). procedure of this instruction or by changing out the
bearing with the generator in place as follows:
23. Install brush holders. Large brush holders
(traction alternators) over collector ring BEARING REMOVAL(Generatoy In Place)
positions 3 and 4 and small brush holders
(companion alternator) over collector ring NOTE
positions 1 and 2. All puller tools used to remove the collector
rings, outer seal, and bearing may be fabricated
24. Attach jumper leads J l,J2,53, and 54 between as detailed in File Drawings and Work Sketch
top and bottom brush holders having the same Drawing listed in Service Data.
numbers. The jumper leads attach to brush
holder locking screws which secure holder to 1. Perform Steps 1 through 8 of Large Bearing
insulated studs. Maintenance procedure.

25. Route leads to the left of the collector ring 2 . Install support tube as shown in Fig. 8. Support
assembly. Secure leads with the cable clamps shaft through a “V” block with an adjustable
bolted to the threaded holes in the bearing jack.
housing.
3. Remove eight 3/4”-10 bolts securing bearing
26. Connect external leads 1, 2, 3, and 4 to housing to the end housing, Fig. 8. Insert four
corresponding lower brush holder terminals. 3/4”-1Ojacking bolts equally spaced around the
bearing housing in jacking holes provided.
27. Adjust brush holders to have 3 mm (I/ 8”) Rotate jacking bolts equally until bearing
clearance over collector rings. In addition, housing is separated from the end housing.
ensure that brush holder is centered over the
collector ring. Torque brush holder locking NOTE
screws to 14-20 N-m (lo-15 ft-lbs). Assemble Some early generator bearing housings had
brushes in holders. If used brushes are re- S/S”-18 jacking holes. Ensure proper bolts are
installed, ensure that the original positions are used.
maintained. Check that each brush is centered
within 1.6 mm (l/ 16”) of the mating collector 4 . Lower the adjustable supporting jack until
ring. rotor rests on stator. Remove the jack and shaft
supporting tube. Slide bearing housing off the
28. Install collector ring cover and sections of air shaft. Remove any burrs from end housing
box covers removed during disassembly. which may have been caused by jacking bolts.

-7-
M.I. 3317-l

Bearing Housing End b. Screw a 1 /V-27 adapter nipple, Fig. 9, into

Jacking Bolt Housing tapped hole in shaft and tighten. Refer to
Service Data for adapter nipple part
number.

c. -Connect hydraulic pump, Fig. 10, to

Shaft Support Tube adapter nipple.

Support Rotor
Weight Through “V”
Block
285-2

Fig.@- Bearing Housing Removal

5. Install rotor shaft jacking fixture as shown in

Fig. 9. Raise rotor until bearing is approxi-
mately centered in the bore of the housing.
Fig.1 0 - Hydraulic Pump

7. If shaft is not equipped for hydraulic bearing

removal, it is necessary to protect the stator and
rotor windings and remove the outer race and
cage with a cutting torch.

8. Thread six puller studs into flange of bearing

cap. Install six spacer tubes and centering ring
as shown in Fig. 11.

9. Place extension yoke around field leads and

bolt extension yoke to shaft as shown in Fig. 11.

{O. Install puller plate. Place assembly jack

between extension yoke and puller plate,
supported by cradle studs of puller plate as
shown in Fig. Il.

Fig.9 - Rotor Shaft Jacking Fixture 1 1 . If rotor shaft is equipped for hydraulic bearing
removal, apply hydraulic pressure to expand
inner bearing race. Maintain this pressure while
6 . if rotor shaft has a tapped hole in the end of the applying hydraulic pressure to the jack
shaft for hydraulic bearing removal. Perform assembly until the bearing slides off the shaft
the following procedure. Two hydraulic pumps seat (approximately 63.5 mm [2-l/27). Ensure
are required to perform the following that puller is pulling equally on all studs to
procedure. prevent damage to bearing.

a. Ensure threads and pressure fitting seat are 1 2 . Lower the rotor with the jacking fixture until it
cleaned in the drilled passagr3 in the shaft. cpntacts the stator. Remove jacking fixture and

-8-
 M.I. 33 17-1

Bearing Cover End Housing

Collect3
Ring

Cable Grommet Out\er Seal i,

Fuller Plate Jacking Fixture
28586
28585

Fig.1 1 - Bearing Removal Fig.1 2 - Bea:ing And Collector Ring

Assembly Cross-Section

pulling equipment. Slide bearing and bearing heating, remove oil from seal with clear;,
cap off the rotor shaft. bound-edge cloths prior to shrinking to the
shaft. When using an induction heater,
13. Examine bearing inner seal for evidence of pyrometer readings (with current off) should be
rubbing. If rubbing appears excessive, remove taken periodically. After heating, shrink the
bearing inner seal, using a small heating torch seal to t.he shaft and allow to cool to room
and pry bars. temperature.

BEARING INSTALLATION Fill labyrinth grooves in the bearing cap with

(Generator In Place) Esso Unirex N-2 grease. This grease need not be
measured. The bearing cap can be distinguished
When all associated bearing parts have been cleaned from the bearing cover by noting that the
and inspected, the bearing is ready for assembly. bearing cap has tapped holes in the flange while
the bearing cover has holes which are not
Before shrinking bearing to rotor shaft, it is very tapped.
important to try the bearing in the housing. Place
bearing housing on the floor and slide bearing Weigh the piece of paper that will be used in
through the bore of the housing. Ensure bearing handling the grease. The weight of the paper
enters bearing housing squarely, and is not cocked. must be compensated for when weighing the
Refer to Service Data for bearing dimensions and grease.
tolerances.
NOTE
Use Lhe following procedure to assemble bearing. Esso Unirex N-2 grease must be used exclu-
Refer to Fig. 12 during assembly. sively to lubricate a new or cleaned bearing.
Adequate lubrication depends upon precise
CAUTION weight of grease. Too much grease is as
Care should be used when heating bearing detrimental to service life of the bearing as too
parts. Overheating may result in warping or little. Bearing replacement kits include pre-
damaging the metal, weighed amounts of grease.

1. If bearing inner seal was removed because of

rubbing, heat a new inner seal in an oil bath, 4. Carefully weigh the‘Esso UIiirex N-2 grease for
electric oven, or induction heater for half an the bearing cap groove. Refer to Service Data
hour at 105’ C (220” F). If an oil bath is used for for proper quantity.

-9-
M.I. 3317-I

Pack the grease into bearing cap groove. Leave Insulating Washer
a space at the top of the bearing, as shown in
Fig. 7 to limit churning and liquefaction of the Hardened
FldtWasher. I Insulating Tube
grease. Form grease to proper contour as
shown in Fig. 7. ~;, I

Install greased bearing cap and a new gasket Insulating Ring

onto shaft.
Polyester Glass Tape
Carefully weigh the Esso Unirex N-2 grease for
-baring Housing
the new bearing. Refer to Service Data for the
proper quantity, Pack the bearing rollers and
Cap Gasket
the space in between the two rows of rollers with
grease.

Heat roller bearing with an induction heater to

105” C (220” F). Take pyrometer readings (with
current off) at outside face of inner race only.
Shrink bearing to shaft with the part number
toward the outside. Do not cock the bearing I I I I U
when placing it on the shaft. Use a brass pipe to
28567
push bearing on shaft and seat firmly against
inner seal. Let bearing cool to room Fig.1 3 - Large Bearing Insulation
temperature.

Thread two l/2”-13 studs, 180” apart, into 15. Position bearing housing so that bearing
bearing cap flange to correctly position cap housing and bearing cover bolt hole pattern
during installation of the bearing housing. relationship is as shown in Fig. 14. This
Ensure gasket is in place. Slide bearing housing relationship is important to position brush
into shaft. holder studs at top and bottom positions.

Apply Molykote paste 9517921 to inside

diameter of bearing housing. TOP
Bearing Housing ,
install two 3/4”-10 aligning studs 180” apart
Bolt Holes \
into two of the eight bearing housing mounting
bolt holes in the end housing. The aligning studs
will help prevent the bearing from cocking
(damaging insulation material), when asscm-
bling bearing housing to end housing.

NOTE
Early IModel AR10 traction alternator with the
small bearing, has a bearing housing with an
inner and outer phenolic sleeve and does not
require additional insulation.

On traction alternators equipped with the large

bearing, position new insulating ring, Fig. 13,
over aligning studs so that holes in the ring line
up with holes in the end housing.

Slide bearing housing over shaft.

Install shaft support tube and supporting jack 22611

as shown in Fig. 8. Raise rotor until bearing is
ccntercd in the bore of the bearing housing. Fig.1 4 - Installing Bearing Housing

- lo-
 M.I. 3317-f

1 6 . Align bearing cap to bearing housing and If the stator has been moved or disturbed,
bearing housing to end housing using the realign generator per M.I. 1753.
aligning studs. Move bearing housing part way
onto bearing. Install special 3/4”-10 x Y’pulling
studs through the bearing housing mounting GENERATOR DISASSEMBLY
holes and into the end housing. DO NOT
ALLOW THE BEARING OUTER RACETO NOTE
BECOME TILTED IN THE BEARTNG If equipment for disassembly and assembly is
HOUSING. Keep the bearing housing parallel not available, generator should be returned to
to the end housing by tightening the pulling the Electra-Motive Division for repair either
bolts only “ a partial turn in 180” pairs before on a rebuild and return, or unit exchange basis.
proceeding to the next pair. Continue to tighten
bolts evenly until the bearing housing is seated. Before the generator is removed from its location,
Remove aligning studs and pulling studs. place strips of fish paper approximately 2 mm x
80 mm x 900 mm (I/ 16” x 3” x 36”) in the bottom air
17. On traction alternator equipped with the large’ gap between the rotor assembly and stator coils.
bearing, install eight insulating tubes into When removing the generator, be sure to tag shims
bearing housing mounting bolt holes. used under mounting pads so they may be replaced
in their original position.
18. On traction alternator equipped with the large
bearing, apply one insulating washer under The following steps apply in disassembling the
each hardened flat washer 953 133 1 and install generator. Refer to Figs. 15 through 20 as applicable
bolts to bearing housing. Torque bearing during disassembly. .
housing bolts to 203 N-m (150 ft-lbs).
1 . Mount generator on a sturdy stand at a suitable
19. Check insulation resistance between bearing working height. Remove dust, dirt, oil, and
housing and end housing, using a 1000 volt grease from outside of generator. This will
megohmmeter. Reading must be a minimum 1 prevent dirt from entering during disassembly.
megohm. If reading is not satisfactory, remove
bearing housing and inspect insulating material
for damage and renew if necessary. 2 . Remove all covers from the generator assembly.

20. Carefully weigh the Esso Unirex N-2 grease for 3. Disconnect leads to brush holder .and
, filter
the bearing cover groove. Refer to Service Data assemblies.
for proper quantity.
4. Remove bolts holding air box to end housing,
21. Pack the grease into bearing cover groove. and carefully remove air box.
Leave a space at the top of the bearing cover to
limit churning and liquefaction of the grease. 5 . Remove’collector rin,g cover, brush holders and
Form grease to proper contour as shown in brush holder bracket assembly.
Fig. 7.
6. Disconnect the phase lead connections and
22. Perform Step 18 through 28 of Large Bearing suppression circuit connections at the bus bars
Maintenance procedure. of each rectifier bank assembly.‘ Remove the
cable cleats securing suppression circuit leads to
NOTE the slides and ends of each rectifier bank
Changing the generator bearing in this manner assembly. Remove rectifier banks.
does not affect engine/ generator alignment,
however, it is recommended that the alignment 7. Remove cleat assemblies securing stator leads
is checked before returning the unit to service. to end housing.
MI. 3317-I

End Housing AR6 Stator Frame AR6 Stator Core

I /

Air Box-

Rectifier
Assembly-

Brush Holder

8L@Ie8
Collector Rinl
Assembly H

Bearing /
i I ;; , ,
Assembly

28588

Fig.1 5 - ARG-D18 Main Generator Cross-Section

 M.I. 3317-I

AR10 Stator Core

AR10 Rotor

Air Box-

- D18 Stator
Rectifier -
Assembly $il
-D18 Rotor

ling
Brush
Holders
\

e al
c3 e
i
Collector Ring
Assembly -

Bearing
/
Assembly

28589

Fig.1 6 - AR1 O-D1 8 Main Generator Cross-Section

- 13-
M.1. 3317-I

End Housing AR11 AR1 1 Stator Core

AR1 1 R n t n r

r-__l 4, :--.1

28590

Fig.1 7 - AR1 ‘l -D18 Main Generator Cross-Section

- 14-
 M.I. 3317-1

End Hntlsino AR1 2 Stator Frame AR1 2 Stator Core

:: L.
,!I
i I1,/
. ! / :::::::::::::::::::::::::::::!
!/ 1
29591

- AR1 Z-D1 4 Main Generator Cross-Section Fig.1 8

- 15-

-
 M.I. 3317-J

End Housing AR1 5 Stator Frame AR1 5 Stator Core

/
r AR1 5 Rotor \
Air Box
---I

Rectifier
Assembly

Brush Holders

rc
J 0 d

3 ’

I!
3

gLj

0 Ll

28592

Fig.1 9 - AR1 5-018 Main Generator Cross-Section

 M.I. 3317-1

End Housing AR1 6 Stator Frame AR1 6 Stato lr core

I /
Rotor

Air Box
--I , D18 Stator

, D18 Rotor

Brush
Holders

Bearing /
Assembly

Fig.20 - AR1 6-D18 Main Generator Cross-Section

M.I. 3317-I

8. Apply an arbor fixture to spider bore of NOTE

companion alternator rotor, Fig. 21. Attach End housing holding fixture may be fabricated
crane cable to end of fixture. as detailed in File Drawing referenced in
Service Data.

10. Insert three 3/4”-10 jacking bolts equally

spaced around end housing in bolt holes from
which end housing mounting bolts were
removed. Turn jacking bolts equally until end
housing is separated from stator frame.

1 1 . Raise arbor fixture until air gap is equal around

circumference of rotor. Raise cable at end
housing until taut.

CAUTION
Use extreme care to ensure that laminations
and windings are not damaged when removing
rotor.

12. Carefully remove rotor and end housing

28594
assembly from stator, moving it towards
bearing end of assembly until it clears stator,
Fig.21 - Application Of Arbor Fixture Fig. 23.

9. Support end housing with another crane cable

and end housing holding fixture, Fig. 22.
Remove eight 3/4”-10 bolts securing end
housing to stator frame.
.~

22588

Fig.23 - Removing Rotor And End

Housing From Stator

NOTE
If necessary, the coupling disc and the
companion alternator rotor can be removed
from the traction alternator rotor.

13. Place rotor assembly on a cradle stand, Fig. 24

with strips of fish paper between rotor and
cradle.

1 4 . Disconnect field leads from collector ring studs,

Fig.22 -Attaching Crane Cable To End Housing Fig. 4 or 5 as applicable.

- 18 -
 M.I. 3317-1

1 8 . Remove puller studs from collector ring

assembly and install original bolts.

1 9 . Install puller plate and puller studs to remove

outer seal as shown in Fig. 6. Place jack
assembly between extension cup and puller
plate supported by cradle studs of the puller
plate. Connect hydraulic pump to jack assem-
bly. Ensure puller is pulling equally on all studs
to prevent damage to outer seal. Apply
hydraulic pressure to jack assembly to remove
outer seal. Remove jack assembly, hydraulic
pump,’ puller plate, and puller studs.

20. Remove bolts from bearing cover, Fig. 4 or 5 as

applicable, and remove bearing cover. If cover
is stuck to bearing housing, hit outer periphery
of cover with a rawhide mallet or similar tool to
remove cover and gasket.

CAUTION
Use extreme care to ensure that bearing
Fig.24 - Rotor Assembly Removed From Stator housing bore is not damaged when removing
the bearing housing from the end housing.
1.5. Remove the four bolts securing the retainer
plate to the end of the shaft, and remove the 21. Remove eight 3/4-10” bolts securing bearing
retainer plate. housing to end housing, Fig. 25. Insert four
3/4”-10 jacking bolts equally spaced around the
16. Remove four 3/8”-16 bolts securing the bearing housing in special holes provided. Turn
collector rings to’the collector ring hub. The jacking bolts equally until bearing housing is
bolts are located on the collector ring face separated from the end housing.
between the lead connection terminals, Fig. 3.
Place extension cup around field leads and bolt Bearing Housing End
cup to shaft as shown in Fig. 6. Jacking Bolt Housing
\

NOTE
All puller tools used to remove collector ring,
bearing outer seal, bearing, and bearing inner
seal may be fabricated as detailed in File
Drawings and Work Sketch Drawing listed in
Service Data.

17. Install puller plate and puller studs to remove

collector ring assembly, as shown in Fig. 6. Bearing
28596
Place jack assembly between the extension cup
and the puller plate, supported by cradle studs Fig.25 - Bearing Housing Removal
of the puller plate. Connect hydraulic pump to
jack assembly to remove collector ring assem- CkJTlON
bly. Ensure puller is pulling equally on all studs Do not wash bearing housing in caustic
to prevent damage to collector ring. Apply solution or cob blast the housing bore. The
hydraulic pressure to jack assembly to remove bearing housing and housing bore dimensions
collector ring. are extremely critical and may be damaged.
M.I. 3317-l

22. If rotor shaft has a tapped hole in the end of the ELECTRICAL INSULATION TEST
shaft for hydraulic bearing removal. Two
hydraulic pumps are required to perform the Before the generator is assembled, it is advisable to
following procedure. electrically qualify the stator, Fig. 26, and rotor. The
following qualifications should be met before any
a. Ensure threads and pressure fitting seat are attempt to give the stator or rotor a high potential
cleaned in the drilled passage in the shaft. test. This applies to any stator or rotor that has had
an occasion for windings to accumulate moisture or
b. Screw a 1 /g”-27 adapter nipple, Fig. 9 into dirt.
tapped hole in shaft and tighten. Refer to
Service Data for adapter nipple part
number.

C. Connect hydraulic pump, Fig. 10, to

adapter nipple.

23. If shaft is not equipped for hydraulic bearing

removal, it is necessary to protect the stator and
rotor windings and remove the outer bearing
race and cage with a cutting torch.

24. Thread six puller studs into flange of bearing

cap. Install six spacer tubes and centering ring
as shown in Fig. 11.

25. Place extension yoke around field leads and

bolt extension yoke to shaft as shown in Fig. 11~

26. Install puller plate. Place hydraulic jack

between extension yoke and puller plate,
supported by cradle studs of puller plate as 13235
shown in Fig. Il.
Fig.26 - Typical AR1 0 Stator Assembly
27. If rotor shaft is equipped for hydraulic bearing
removal, apply hydraulic pressure to expand 1. Stator and rotor must be clean
inner bearing race. Maintain this pressure while
applying hydraulic pressure to the jack assembly 2. Stator and rotor must show a steady insulation
until bearing slides off the shaft seat (approxi- resistance reading for at least three hours at any
mately 63.5 mm [2-l / 2”]). Ensure puller is given temperature from 75” C to 90” C (167“ F
pulling equally on all studs to prevent damage to 194” F).
to bearing.
3. The ratio of insulation resistance taken 5
28. Remove bearing inner seal using small heating minutes after starting the megger check should
torch and pry bars. not beless than l-1/2times thereadingtaken 10
seconds after starting the check. The check
29. Remove companion alternator stator closure should be taken with a stator temperature
assembly, if necessary. reading of 50” C (122’ F).

30. Ensure the companion alternator stator 4. The insulation resistance of the rotor must be
assembly is properly supported and remove not less than one megohm at any temperature
bolts securing the companion alternator stator up to 75” C (167’ F).
assembly to the traction alternator stator
assembly.&stall3/4”- I Ojack bolts and remove Any stator or rotor which, although clean, shows
the companion alternator stator assembly. low or erratic insulation resistance readings, should
 M.I. 3317-I

be dried at 90” C (194” F) until a stabilized CLEANING

insulation resistance reading is obtained for a period
of twenty-four hours. Before applying high potential Before attempting to make any inspection, a bearing
test, all the other qualifications outlined must be must be thoroughly cleaned. Stoddards solvent or
met. similar no:!corrosive solvent having a flash point of
46’ C (115” F) or higher may be used.
N O T E
Generators which have been stored for a A clean brush or lintless cloth can be used to
considerable period of time should be given an facilitate cleaning. Gasket surfaces should be given
insulation resistance check before being put special attention to remove all traces of remaining
into service. gasket material.

HIGH ~~OTENTIAL TEST NOTE

If bearing components are not to be used
If the stator and rotor meet the listed qualifications, immediately after inspection they should be
test should be taken at 50” & 5” C (122” f 9” F) in coated with Esso Unirex N-2 grease to prevent
the following manner: corrosion while in storage.

1. For stators. short all positive and negative bus OPERATING SURFACES
bars. DO NOT PERFORM HIGH-POTEN-
TIAL TESTS BEFORE CONSULTING All exposed operating surfaces must be inspected
M.I. 3317-2. visually to ensure that they contain none of the
following defects which will be cause for rejection:
2 . Apply 1050 volts RMS to stator for one minute.
1. Wear - A properly lubricated bearing not
3. Apply 300 volts to rotor for one minute. subjected to misalignment, dirt, or distortion
will show no evidence of wear. The internal
If the stator or rotor fails to qualify either the radial clearance of the bearing may be checked
resistance check or the high potential test, the by passing a feeler gauge between the rollers
generator should be returned to the Electra-Motive and race of the unloaded side of the bearing. Do
Division due to the special tooling and facilities not roll a feeler through a bearing. For limits,
needed to make corrections. see Service Data.

BEARING INSPECTION 2. Fatigue Failure - Signs of fatigue failure will

most usually appear on the bearing surface.
GENERAL ’ Fatigue failure is usually evidenced as ragged
craters, and may be of any size. Any bearing
On all bearings with appreciable service, some showing any sign of cracks or craters of any
dents, nicks, pits, and craters will be found. If these size, regardless of how small they may be,
are small and scattered, they should not be cause for should be replaced. This type of failure is more
rejection; however, they should be evaluated with likely to occur on either the rollers or inner race.
good judgement and with reference to the overall
condition of the bearing. All doubtful parts should 3. Protrusions above the normal surface.
be discarded. Failed parts should be replaced with
either new or acceptable reconditioned parts. If one NOTE
part of an assembly has been subjected to excessive Protrusions should be reduced to the normal
stress which results in a visible defect severe enough surface by iight circumferential honing with‘
to reject the part, the rest of the assembly requires a Arkansas stone (novaculite) or grade 240
detailed inspection and evaluation before reuse. abrasive cloth. Likewise, the sharp edges
should be smoothed. Care must be taken to
The roller bearing should be thoroughly inspected work down to the normal surface only, to
for possible evidence of impending failure. The prevent reduction of contact area, and to work
following inspections are to be used when qualifying circumferentially so as to prevent the formation
bearing components for reuse. of flats.

-21
M.I. 33 17-l

4. Cracks and flats. 2. Weigh the piece of paper that will be used in
handling the grease. The weight of the paper
5. Ruptures, tears or seams (2.4 mm [3/32”] or must be compensated for when weighing the
more in length, or more than hairline width). grease.

6. Scores, or deep scratches which extend more NOTE

than 3/4 the length of the operating surface and Esso Unirex N-2 grease must be exclusively to
are inclined at less than 10” to the axis. lubricate a new or cleaned bearing. Adequate
lubrication depends upon precise weight of
7. Corrosion pits. (0.8 mm [l/32] or more in grease. Too much grease is as detrimental to
diameter.) service life of the bearing as too little. Bearing
replacement kits incl.ude preweighed amounts
8. Craters or pits from electrical arcing. (0.8 mm of grease.
[ l/32] or more in diameter.)
3. Carefully weigh the Esso Unirex N-2 grease for
9. Profuse denting. the bearing cap and cover groove. Refer to
Service Data for proper quantity.
IO. Overheating.
4. Pack the grease into bearing cap and cover
11. Circumferential pattern of pits or dents at the groove. Leave a space at the top of the bearing,
ends of the roller path. as shown in Fig. 7, to limit churning and
liquefaction of the grease. Form grease to
12. Fatigue pits, flaking, shelling or galling. proper contour as shown in Fig. 7.

GENERATOR ASSEMSLY
5. Clean armature shaft and remove burrs or gall
NOTE marks.
The main generator consists of an AR-type
traction alternator and a companion CAUTION
alternator. Care should be used when heating bearing
parts. Overheating may result in warping or
After the generator stator and rotor have been damaging the metal.
cleaned and checked, the inside of the stator and the
outside of the rotor should be painted with red air 6 . Heat the inner seal in an oil bath, electric oven,
drying enamel. or induction heater for half an hour at 104” C
(220’ F). If an oil bath is used for heating,
When all the component parts have been cleaned, remove the oil from the seal with clean, bound-
checked inspected, and painted, the generator is edge cloths prior to shrinking to the shaft.
ready for assembly. Whenusing an induction heater, pyrometer
readings (when current off) should be taken
Refore shrinking bearing to rotor shaft, it is very periodically. After heating, shrink the seal to
important that the bearing be tried in its housing. 1 the shaft and let it cool to room temperature.
Place bearing housing on floor and slide bearing
through bore of housing. Ensure bearing enters the
housing bore squarely, and is not cocked. See 7. Install greased bearing cap with gasket onto
Service Data for bearing dimensions and tolerances. shaft.

Refer to Figs. 15 through 20 as applicable during 8. Pack the bearing rollers and the space between
assembly. the two rows of rollers with the quantity and
type of grease specified. in Service Data. On
BEARING AND END large bearings, fill groove in outer race with
HOUSING ASSEMBLY additional grease.

1. Fill labyrinth grooves in the bearing cap and NOTE

cover with Esso Unirex N-2 grease. This grease If Shell Cyprina grease is present in the
need not be measured. bearing, Esso Unirex N-2 may be added.

- 22 -
 M.l. 3317-l

9 . Heat roller bearing with an induction heater to 1 megohm. If reading is not satisfactory,
105” C (220’ F). Take pyrometer readings (with remove bearing housing and inspect insulating
current off) at outside face of inner race only. material for damage and renew if necessary.
Also see Caution before Step 6. Shrink bearing
to shaft with the bearing part number toward
the outside. Do not cock the bearing when 18. Insert two L/2”-13 aligning studs, Fig. 27, 180”
placing it on shaft. Use a brass pipe to push apart in the threaded holes in the bearing cap.
bearing on shaft up to and against inner seal. The purpose of the studs is to guide the bearing
Let bearing cool to room temperature. housing to the bearing cap. A bearing alignment
disc, Fig. 27, may also be used in installing the
10. Place end housing in a horizontal position with end housing.
mountingflange down, and install two 3/4”-10
aligning studs 180* apart into two of the eight NOTE
tapped bearing housing bolt holes in the end Bearing alignment disc may be fabricated as
housing. The aligning studs will help prevent detailed in the File Drawing referenced in
the bearing from cocking (damaging insulation Service Data.
material) when assembling bearing housing to
end housing. 9. Lift end housing and place over rotor shaft.
Align bearing housing to bearing cap using the
NOTE aligning studs. Being careful not to cock
Small bearing Model AR10 traction alternator bearing housing on bearing, gently push end
has a bearing housing with an inner and outer housing onto bearing until housing is snug
phenolic sleeve and does not require additional against bearing cap. Remove aligning disc.
insulation.

Il. On traction alternator equipped with large 20. Apply new gasket to bearing cover, Fig. 13.
bearing, position new insulating ring, Fig. 13, Mount bearing cover to bearing housing xitih
over aligning studs so that holes in the ring line brush holder studs located at top and bottom
up with the holes in the end housing. positions. Remove aligning studs and secure
cover with l/2”-13 cover mounting bolts hand
1 2 . Apply Molykote paste to inside diameter of tightened. When all bolts are installed hand
b&&g housing prior to assembling bearing tight and the cover is not cocked, torque bolts to
housing to bearing. 68-75 N-m (50-55 ft-lbs) using a minimum of
three passes.
1 3 . Position bearing housing so that bearing
housing and bearing cover bolt hole pattern CAUTION
relationship is as shown in Fig. 14. This Do not heat seal above 104” C (220” F).
relationship is important to position brush Overheating may result in warpage or other
holder studs at top and bottom position. damlge
“b to seal.

1 4 . Carefully lower bearing housing into position 21. Heat outer seal in an oil bath or electric oven,
guided by aligning studs. Gently tap bearing for half an hour at 104” C (220’ F). If oil bath
housing until bearing housing bottoms out on method is used, remove oil from seal with clean
the end housing. Remove aligning studs. bound edge cloths prior to shrinking to rotor
shaft. When using an induction heater,
1 5 . On traction alternator equipped with large pyrometer readings (with current off,) should be
bearing, install eight insulating tubes into taken periodically. After heating, shrink outer
bearing housing mounting bolt holes. seal to rotor shaft by letting it cool to room
temperature.
1 6 . On traction alternator equipped with the large
bearing, apply one insulating washer under 2 2 . Place collector ring assembly on induction
each hardened flat washer 953 133 1 and install heater and heat to 104” C (220” F). Pyrometer
bolts to bearing housing. Torque bearing readings (with current off) should be taken
housing bolts to 203 N-m (150 ft-lbs). periodically. After heating, piace collector ring
assembly on rotor shaft, against outer seal.
1 7 . Check insulation resistance between bearing Rotate ring assembly on shaft for proper
housing and end housing, using a 1000 volt position of lead connection to terminals of ring
megohmmeter. Reading must be a minimum of assembly.

- 23 -
M.I. 3317-1

End Housing Holding Fixture

Aligning
Disc
-I
Aligning \ d
Studs
\

22612

Fig.27 - Applying End Housing To Rotor Assembly

WARNING s h a f t . T o r a u e b o l t s t o 5 0 8 - 5 4 2 N*m
If work involving collector ring connections (375-400 ft-ibs) using a minimum of three
has been performed, use a continuity tester passes.
(with all field leads disconnected and all
brushes lifted) to check that collector ring 2. Bolt companion alternator stator assembly to
terminals marked 1 through 4 on the steel hub traction alternator stator frame assembly.
adjacent to the terminals are connected to the Torque mounting bolts to 271 N-m (200 ft-lbs).
appropriate collector rings (No. 1 outboard,
No. 4 inboard). NOTE
A new generator/ engine coupling arrangement
23. Place retainer plate over leads and on to the end designed to reduce vibration levels has been
of rotor shaft. Torque the S/S”-1 1 retainer plate applied since January 1983.
mountingboltsto 149-163N*m(llO-120ft-lbs).
The new coupling arrangement applies and engine
24. Install cable grommet over four field leads and coupling with a thin cross-section and a generator
insert grommet into retainer plate. coupling disc with a thick cross-section, rather than
the thick engine coupling/ thin generator coupling
25. Connect large field leads (traction alternator) to disc arrangement. The mating surfaces of the new
collector ring terminals 3 and 4, and smaller arrangement are designed to prevent misapplication
field leads (companion alternator) to terminals Refer to Fig. 28.
1 and 2. Secure leads by torquing mounting
bolts to lo-12 N*m (7-9 ft-lbs). 3. Apply coupling disc to companion alternator
rotor hub. Lubricate threads, washer and
ROTOR AND STATOR ASSEMBLIES washer face of self locking nut with Molykote.
Torque mounting nuts to 1898-2034 N*m
1. If companion alternator rotor assembly was (1400-1500 ft-lbs).
removed from main generator rotor, align
mating bolt holes and bolt rotors together using 4. Place stator assembly and rotor assembly on
7/8”-9 bolts removed during disassembly. Be their stands close enough to each other so that
sure companion alternator cable leads are when the arbor fixture is placed in the flange
threaded through the traction alternator rotor bore of the companion alternator rotor, the end

- 24 -
 M.I. 331771

Generator Engine Generator Engine

Disc Coupling Disc Coupling
,:”
Previous New
Arrangement Arrangement

26597

Fig.28 - Engine/Generator
Coupling Arrangement

of the fixture protrudes through the stator NOTE

assembly, as shown in Fig. 29. At the time of manufacture, the total end
movement measurement of the bearing within
NOTE the bearing housing is stamped on the
Arbor fixture may be fabricated.as detailed in generator end housing. On current generators,
the File Drawing referenced in Service Data. this dimension is 9.5 mm i 0.4 (3/ 8” f l/64”).
A few early generators had a total end
movement less than 9.5 mm, which can be
verified by the figure stamped on the generator
end housing. This dimension is required to
determine that the bearing has the necessary
clearance.

During manufacture, measurement is also

taken to determine bearing thrust clearance
(called the “X” dimension) and is stamped on
the generator end housing. This dimension is
used, to position the generator when being
connected to the engine to provide bearing
thrust clearance to prevent bearing damage.

6. Center the rotor assembly in the stator and

check the total end movement of the bearing
22613 outer race in the bearing housing. A few early
generators had a total end movement of less
Fig.29 - Preparation To Install Rotor In Stator then 9.5 mm f 0.4 mm (3/S” f l/64”) which can
be verified by the figure stamped on the
5 . Support end housing with a crane cable and end generator housing. All current generators and
housing holding fixture, Fig. 30. Support end of most earlier models have a total end movement
arbor fixture with another crane cable. of 9.5 mm f 0.4 mm (3/8” f l/64”). If the
Carefullylift and guide rotor assembly into original parts are’reused, this figure may be the
stator. Avoid ‘damaging insulation. When end same as the original figure which was stamped
housing is flush against stator frame, install on the face of the generator end housing. If the
3/4”-10 bolts, and lockwashers, to hold end total end movement measurement differs from
housing to stator frame. Torque bolts to the number stamped on the generator end
271 N-m (200 ft-lbs) using a minimum of three housing, Fig. 3 1, remove the original number
passes. and stamp the new number adjacent to it.

- 25
 22614

Fig.31 - Stamped Dimensions On

Generator End Housing
Fig.32 - Model AR1 0 Small Bearing “X”
7 . Position the rotor so that all the end movement (Protrusion) Measurement
is taken up in the direction of the coupling disc.

On early model AR IO generators with the small

bearing application, measure the distance from
the machined surface of the bearing housing
between the mounting bolts to the outer surface
of the collector ring assembly, Fig. 32. This
measurement is the “X”(protrusion) dimension.
Stamp this measurement, to the nearest
0.40 mm (I /64”), on the generator end housing,
Fig. 3 1. This dimension should be approxi-
mately 224.6 mm (g-7/8”).

On the other model generators with the large

bearing application, measure the distance from
the bearing housing bolt head at the I o’clock
position to the outer surface of the collector
ring assembly, Fig. 33. This measurement is the
“X” (protrusion) dimension. Stamp this
measurement, to the nearest 0.40 mm (l/64”),
on the generator end housing, Fig. 31.

On AR6, 10, 12, and 15 generators, this

dimension should be approximately 203 mm Fig.33 - Large Bearing :‘X”
(g”), and on the AR1 1 and 16 generators, (Protrusion) Measurement
approximately 300 mm (ll-13116”).
9. Install brush holders, Fig. 4 or 5 as applicable.
8 . Place fish paper strips 2 mm x 80 mm x 900 mm Large brush holders (traction alternator) over
(I/ 16” x 3” x 36”) in air gap between rotor collector ring posit.ions 3 and 4, and small brush
assembly and stator. Remove crane cables and holders (companion alternator) over collector
end housing holding fixture. ring positions 1 and 2.
.i
 M.I. 3317-l

10. Mount jumper leads JI, J2,53, and 54 between together leads CTA, CTB, and CTC on
top and bottom brush holders having the same outside of the air box.
position numbers. The jumper leads attach to
brush holder locking screws, which secure 2. Take cold, 75” C (167” F), resistance readings.
hoider to insulated stud. Refer to Service Data for limits.

Il. Route leads to left of collector ring assembly. HIGH POTENTIAL TEST
Secure leads with three cable clamps bolted into
threaded holes in bearing housing. The insulation used in these generators is designed
to withstand somewhat higher voltages than those
experienced during normal operation.
12. Connect external leads 1, 2, 3, and 4 to
corresponding lower brush holder terminals. High potential tests are normally used when it is
necessary to qualify new equipment instailations or
13. Adjust brush holders to have 3.2 mm (I/S”) to determine the location of an insulation
cIearance over collector rings. In addition breakdown on older equipment. High potential
ensure that holder is centered over collector tests can be destructive to equipment being tested
ring. Torque holder locking screws to and, therefore, are not recommended as a normal
14-20 N-m (lo-15 ft-lbs). Assemble brushes in routine maintenance item.
holders; if used brushes are reinstalled ensure
that their original positions are maintained. In some cases, such as; national or local code
Check that each brush is centered within requirements, company policy, or a suspected
1.59mm(l/l6”) in relation to mating collector insulation breakdown, high potential tests are
ring. required. In these instances adhere to all cautions,
listed below in the Safety Precautions section, while
14. Install rectifier banks on end housing. performing test.

1.5. Install stator lead cleat assemblies to face of end If the rotor or stator fail the high potential test it is
housing and connect stator leads to rectifier recommended that it be returned to Electra-Motive
bank assemblies. Division because of special tooling and facilities
required to make repairs.
16. Install collector ring cover and air box cover
assembly removed during disassembly. SAFETY PRECAUTIONS

17. Connect all loose leads to proper connections Whenever possible, high potential tests should
and secure with tape to prevent movement. be performed by one man. All others should be
Route remaining external leads through hole kept away from the test area.
on lower face of air box.
A thorough knowledge and understanding of
Generator is now ready to be tested, refer to equipment, and procedures involved is
Generator Testing. When tests are complete, refer to essential.
Installation Of Main Generator Into Locomotive
Unit. To prevent dangerous overvoltage surges, test
electrodes must be firmly connected to item
GENERATOR TESTING IIJI&L tm.t. kfwx,~Jhsg..k wp$k&. ‘a, ,uik!itirvr,,
the voltage should be removed before the
1 . Prepare generator for testing by performing the electrodes are removed.
following preliminary steps:
Discharge residual voltage to ground after
a. Clean out and inspect generaior for stray removing tester.
-_ ’
inaterial, steel cuttings, etc.
Before high potential tests are made, it is highly
b. Disconnect suppression circuitry from desirable to check first with a megohmme’ter. A
rectifier bridges and AC paralleling bars. megohmmeter reading of I megohm, when tested
with a 1000 V megger, is satisfactory for hi-pot test.
c. Generators equipped with current trans- An accumulation of dirt and moisture sometimes is
formers should have the current trans- sufficient to cause leakage and, if high potential is
formers short circuited by securely bolting applied, it will cause an actual breakdown of the

- 27 -
M.I. 3317-1

insulation. The. condition may be aggravated by Before a main generator is installed, check and clean
sudden temperature changes. If the equipment has the mounting plates. Be sure these plates are
been standing outside during cold weather before smooth, free of burrs and high spots. I
being brought inside a warm building, the equip-
ment will tend to sweat and the condensed moisture Before lifting the generator into the unit, check and
will aid the leakage effect. clean the mounting pads on the locomotive bed
frame. Be sure these pads are clean and free of burrs.

The normal voltage of EMD main generators is Check the surface on the engine and generator
600 volts. Therefore, the minimum test voltage coupling discs, both must be smooth and clean. Add
should be: a little oil or mounting compound to the fitting
surfaces. Check that bolt holes in couplings are
Generator . . . . . . . . . . . . . . . . 950 volts clean and smooth.
High voltage wiring and
high voltage equipment . . . . . . 1050 volts Apply 2-3/S* socket wrench to the engine and
generator coupling bolt nuts to make sure they are
In making high potential tests, the following tightened to the proper torque as specified in Service
precautions should be taken. Data.

Inspect and clean shims. Shims must be smooth,

WARNING free from burrs and kinks. Shims should have been
Make sure that all personnel are in the clear tagged after removal of generator so they may be
before applying voltages. installed in their original position at this time.

1. All high potential tests must be made by placing Lift generator and guide slowly and carefully into
electrodes on the circuit under test before engineroom. Set generator on mounting pads as
closing switch, and opening switch before close to engine coupling disc as possible.
removing electrodes. Dangerous over-voltage
surges may result from making or breaking the Line up hole patterns in the engine and generator
high voltage circuit with the electrodes. coupling discs by barring or jacking engine over.
Push generator toward engine until engine coupling
fits into the beveled groove in the generator
coupling disc.
2. It is of utmost importance, that a reliable high
potential tester .be used to ensure that an Check all coupling bolts to see that they are smooth
adequate test is made, and that unnecessary and clean. Place a little oil or mounting compound
overstressing of insulation does not take place. on 3/4” coupling bolts and install all bolts through
In regard to the features which should be the generator and engine coupling discs from the
incorporated in a high potential tester, the engine side. Check to be sure the generator coupling
following points are pertinent: is not cocked and is properly mated to the engine
coupling disc.
a. Wave form
b. Surges Once the generator is attached to the engine, do not
c. Voltage regulation bar or jack engine over until all fish paper strips are
removed from between the rotor assembly and the
INSTALLATION OF stator coils.
MAIN GENERATOR INTO
Line up dowel holes and base bolt holes. Do not
LOCOMOTWE UNIT insert dowels or base bolts until generator is aligned
with engine. See M.I. 1753 for alignment of
The installation of the main generator is similar to generator to engine. Install dowels and base bolts.
removal, with the exception that it requires more Use Texaco Threadtex as a lubricant on the bolts
time, care and skill. and washers.

- 28 -
 M.I. 3317-1

SERVICE DATA
REFERENCES
ARIO, AR12, AR15, AR16-D14 or D18 Traction Generator
Rectifier Bank Assemblies And Suppression Circuits s . . , . . . . . . . . . . . . . . . . M.I. 3317-2

AR 11 Traction Generator Rectifier Bank Assemblies

And Suppression Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . 0. . * m. . . ‘. . M.I. 3317-3

D14 Alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M.I. 3306

D18Alternator . *. . . . . . . . . . . . . . *. . . . . . . . . . . . . . . . . . *. . . . . . . . M.I. 3307

Alignment Of Locomotive Rotating Equipment . a e . . . . . . . . . . 0a . . . . . . . . . . . M.I. 1753

SPECIFICATIONS
Weights

AR6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 030 kg (13,300 lbs)

AR10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 120 kg (15,700 Ibs)
AR11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7440kg(16,400lbs)
AR12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8225kg(18,130\bs)
AR15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 985 kg (15,400 lbs)
AR16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 330 kg(18,360lbs)

Brushes
Number of Brushes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Grade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Brush Part Number
Used With Single Brush Holder 8413189 (Current Model) . . . . . . . . . . . . . . . . . . . 8413191
Used With Double Brush Holder 8283003 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8329.691
Used With Double Brush Holder 8455030 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8456279
Brush Size
8413191 (Current Model)- . . . . . . . . . . . . . 54mmx32mmx 13mm(2-l/X”x’l-1/3”x l/2”)
8329691,8456279 . . . . . . . . . . . . . . . . . . . . 51 mm x 32 mm x 13 mm (2” x l-114” x l/2)
Wear Limit . . . . ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 mm (3/4”f
Brush Holder 8413189 (Current Model)
Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Brush
SpringHolder
Pressure
82830d3. . . . . . . . . . . . . . . . . . . . . . . . . . . 1.50 kg + 0.15 kg (3.3 f 0.33 lbs)

Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Brllsh
SpringHolder
Pressure
8455030. . . . . . . . . . . . . . . . . . . . . . . . . . 1.49 kg f 0.11 kg (3.29 + 3.25 Ibs)

Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Spring Pressure 1.50 kg + 0.15 kg (3.3 + 0.33 lbs)
(For D14 brushes and bruskhoidkrs,‘see’h;.i.‘3;06j ’ *’ ’ ’ . ’ **’ ’
(For D18 brushes and brush holders, see M.1. 3307)
Collector Rings
Maximum Ring Eccentricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.15 mm (0.006”)
Maximum Lateral Ring Runout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8 mm (l/32”)
Condemning Limit On Ring Outside Diameter . . . . . . . . . . . . . . . . . . . . 260 mm (IO-1 /4”)

- 29 -
M.I. 3317-I
AR10 Generators Built
Current Generators Prior to Nov., 1971

Roller Bearing

Outer Diameter . . ~ . . . . . . . . . . . . . 259.999 mm ‘“,‘iii :z

+o.oooo~) +o.oooofl)
(10.2362” -o oo14”) (8.4646” -0.0012”)

Bearing Bore . . . . . . . . . . . . .

+o.oooo~) +o.oooo~)
(4.7244” (4.7244’;
-o.ooosv) -0.0008~)

+O.OO mm $0.00 mm
Width . . . . . . . . . . . . . . . . . . . . 86.000 mm -o 13 mn~ 58’oo’ mm -0.13 m*n

+o .OOW) +o.ooo-)
(3.3858” (2.2835”
-o.oo5n) -0.005”)

lnternal Clearance . . . . . . . . . . , . . . . . 0.104 mm to 0.150 mm 0.114 mm to 0.155 mm

(before assembly) (0.0041” to o.oo59V) (0.0045” to 0.0061”)

Internal Clearance . . . . . . . * . , . . . . . . . . . 0.064 mm min. 0.08 mm min.

(after a&embl$) (0.002Y min.) (0.003” min.)

Bearjng Housing’Bore Inside Diameter , . .

+0.0010”)
(8.4705” -0.0000”)

Lubricant Capacity
Bearing Cap . . . . . .................. 284 g (10 ozs.) 170 g (6 ozs.)
Bearing . . . . . . . . . . . . . . . . . . . . . . . . . . 369 g (13 02s.) 113 g (4 OS)
Outer Bearing Cover . . . . . . . . . . . . . . . . . . . 284 g (10 02s.) 170 g (6 ozs.)
- -
Total 937 g (33 02s.) 453 g ( 16 ozs.)
 M.I. 3317-I

COLD RESISTANCE LIMITS (In Ohms At 75” C)

MODEL AR6

Rotor Collector Ring To Collector Ring

Nominal
1.020
Nominal
-i--Tic
-l-2% -2%
Stator Line-To-Neutral
Per 5 Phase Group 0.00476 0.00485 0.00466
Stator Line-To-Line
Per 5 Phase Group 0.00903 0.0092 1 0.00885
Nornina! f8% -8%
Stator Line-To-Neutral
Per Paralleled 10 Phase Group 0.00272 0.00294 0.00250
Nominal
Stator Line-To-Line
Per Paralleled 10 Phase Group 0.00497

MODEL AR10
Nominal +4%
Rotor Collector Ring To Collector Ring 1.238 1.288
Nominal
Stator Line-To-Neutral
Per 5 Phase Group 0.00308 0.00314 0.00302
Stator Line-To-Line
Per 5 Phase Group 0.00568
Nominal
Stator Line-To-Neutral
Per Paralleled 10 Phase Group 0.00 176
Nominal
Stator Line-To-Line
Per Paralleled 10 Phase Group 0.00312 0.00328 0.00296
MI. 3317-I

COLD RESISTANCE LIMITS (CONTINUED)

MODEL AR1 1
Nominal -l-4% -4%
Rotor Collector Ring To Collector Ring 1.238 1.288 1.188
Nominal +20/o -2%
Stator Line-To-Neutral
Per 5 Phase Group 0.000876 0.000890 0.000866
Stator Line-To-Line
Per 5 Phase Group 0.00 142 0.00145 0.00139
Nominal +8% -8%
Stator Line-To-Neutral
Per Paralleled 10 Phase Group 0.000500 0.000545 0.000465
Nominal +5% -5%
Stator Line-To-Line
Per Paralleled 10 Phase Group 0.00078 0.00082 0.00074
+

MODEL AR12
Nominal $2-l/2% -2-l/2%
Rotor Collector Ring To Collector Ring 1.48 1.52 1.44
Nominal 4-Z% -2%
Stator Line-To-Neutral
Per 5 Phase Group 0.00242 0.00247 0.00237
Stator Line-To-Line
Per 5 Phase Group 0.00444 0.00453 0.00435
Nominal +5% -5%
Stator Line-To-Neutral
Per Paralleled 10 Phase Group 0.001380 0.001450 0.001310
Stator Line-To-Line
Per Paralleled 10 Phase Group 0.00253 0.00266 0.00240

- 32 -
 M.I. 3317-1

COLD RESISTANCE LIMITS (CONTINUED)

r--
MODEL AR15
Nominal f4%
Rotor Collector Ring To Collector Ring 1.238 1.288
I - - - - -
Nominal f2%
Stator Line-To-Neutral
Per 5 Phase Group 0.00300 0.00306
Stator Line-To-Line
Per 5 Phase Group 0.00555 0.00566

MODEL AR16
Nominal f4% -40/O
Rotor Collector Ring To Collector Ring 1.635 1.701 1.570
Nominal +2% -2%
Stator Line-To-Neutral i
Per 5 Phase Group 0.001455 0.001484 0.001426
Stator Line-To-Line
Per 5 Phase Group 0.002729 0.002784 0.002674

- 33 -
M.I. 3317-I

Coupling Disc Torque (Lubricated with Texaco Threadtex)

Six 3011 Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2440 N-m (1800 ft-lbs)
Twelve Bolt Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1830 N-m (1350 ft-lbs)
Engine To Generator Coupling Bolt Nut Torque . . . . . . . . . . . . . . . . . . . 400 N*m (295 ft-lbs)

Pyrometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8364533
Induction Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8041446
Stone (1” x i-112” x 5”) - 2 required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8204167
Collector Ring Grinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8219264
Col!ector Ring Grinder Adapter:
Small Bearing (215 mm) Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8364940
Large Bearing (260 mm) Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9506268

NOTE
Two hydraulic pumps are required for bearing removal if rotor shaft has tapped hole for hydraulic
bearing removal.

Hydraulic Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 174285

Hydraulic Pump Hose Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8152395
Hydraulic Pump Oil, 1 gal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8246430
Adapter Nipple, I / 8”-27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8458505
Megohmmeter Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9548311
High Potential Tester . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8324253, 8212404
Aligning Stud (3/4”-IO x 8-!/4”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8458481
Jacking Boil (3/4”-10 x 5V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8458523
Generator Lifting Shackle - Includes Pin - 2 required . . . . . . . . . . . . . . . . . . . . . . . 8249739
Shackle Base - 2 required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8072352
Shackle Base Bolts - 8 required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272563
Rotor Shaft Jacking Fixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . *Work Sketch 16288
Grease Contour Mask, Bearing Cap And Cover . . . . . . . . . . . . . . . . . . . . *File Drawing 9 I9
End Housing Holding Fixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “File Drawing 753
Arbor Fixture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . *File Drawing ‘754
Collector Xing, Seals, and Bearing Puller Assembly . . . . . . . . . . . . . . . . . . *Fi!e Drawing 755
Bearing Alignment Disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . *File Drawing 920

* FiIe and work sketch numbers represent facility drawings that are available (at no charge) from EMD
Service Publication Department. These drawings include construction details of tooiing that can be
manufactured by the customer.

Texaco Thrcadtex 18.93 liters (5 gal!ons) .. . . . . . . . . . . . . . . . . . . . . . 830773 1

Krd Air Drying Enamel (Water Based)
.95 Iilers (1 quart) . . . . . . . . . . . . . . .......... . . . ...... 8061130
i8.?3 liters (5 gallons) . . . . . . . . . . . . .......... . . . . . . . . . 8084876
Molykote Lubricant .473 liters (I pint) pasie .......... . . . . . . . . . 9517921
Bearing Lubricant . . . . . . . . . . . . . . . .......... . . . . Esso Unirex N-2
13.61 kg (35 lb) . . . . . . . . . . . . . . . . . . . . . 9507 146
54.43 kg (ii0 ib) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9507147

- 34 - Litho in U.S.A