TM-360 l+oBARr”TM-360 Exciter Armature Service Manual GROUND POWER 3. Exciter Armature Replacement a. General As stated earlier, exciter armature removal is often required for rear

TM-360 013194 l+oBARr”

GROUND POWER

h-vice Manual

for

Removal and Installation

of

ENGINE-DRIVEN GENERATOR EXCITER ARMATURES

used on

Aircraft Ground Power

Generator Sets

manufactured by HOBART BROTHERS COMPANY

Power Systems Group Troy, Ohio 45373 !

U.S.A. 1

This page intentionally leff blank.

Safety Instructions and Warnings for Electrical Power Equipment

ELECTRIC ARC FLASH can injure eyes, burn skin, cause equipment damage, and ignite combustible material. DO NOT use power cables to break load and prevent tools from causing short circuits.

IMPROPER PHASE CONNECTION, PARALLELING, OR USE can damage this and attache equipment.

~fTlpOt$GIlt: Protect all operating personnel. Read, understand, and follow all instructions in the OperatingAnstruction Manual before installing, operating, or servicing the equipment. Keep the manual available for future use by all operators.

a. General Equipment that supplies electrical power can cause serious injury or death, or damage to other equipment or property. The operator must strictly observe all safety rules and take precautionary actions. Safe practices have been developed from past experience in the use of power source equipment. While certain practices below apply only to electrically-powered equipment, other practices apply to engine-driven equipment, and some practices to both.

1. Shock Prevention Bare conductors, or terminals in the output circuit, or ungrounded, electrically-live equipment can fatally shock a person. Have a certified electrician verify that the equipment is adequately grounded and learn what terminals and parts are electrically HOT. Avoid hot spots on machine. Use proper safety clothing, procedures, and test equipment.

The electrical resistance of the body is decreased when wet, permitting dangerous currents to flow through it. When inspecting or servicing equipment, do not work in damp areas. Stand on a dry rubber mat or dry wood, use insulating gloves when dampness or sweat cannot be avoided. Keep clothing dry, and never work alone

a. Installation and Grounding of Electrically Powered Equipment

Equipment driven by electric motors (rather than by diesel or gasoline engines) must be installed and maintained in accordance with the National Electrical Code, ANSVNFPA 70, or other applicable codes. A power disconnect switch or circuit breaker must be located at the equipment. Check the nameplate for voltage, frequency, and phase requirements. If only 3-phase power is available, connect any single-phase rated equipment to only two wires of the 3-phase line. DO NOT CONNECT the equipment grounding conductor (lead) to the third live wire of the 3-phase line, as this makes the equipment frame electrically HOT, which can cause a fatal shock.

Always connect the grounding lead, if supplied in a power line cable, to the grounded switch box or building ground. If not provided, use a separate grounding lead. Ensure that the current (amperage) capacity of the grounding lead will be adequate for the worst fault current situation. Refer to the National Electrical Code ANSVNFPA 70 for details. Do not remove plug ground prongs. Use correctly mating receptacles.

b. Output Cables and Terminals

Inspect cables frequently for damage to the insulation and the connectors. Replace or repair cracked or worn cables immediately. Do not overload cables. Do not touch output terminal while equipment is energized.

1 !

Safety Instructions 910082 Sept l/90 Page i

c. Service and Maintenance

This equipment must be maintained in good electrical and mechanical condition to avoid hazards stemming from disrepair. Report any equipment defect or safety hazard to the supervisor and discontinue use of the equipment until its safety has been assured. Repairs should be made by qualified personnel only.

(I) Befo@ inspecting or servicing electrically-poweted equipment, take the following precautions:

(2) Shut OFF all power at the disconnecting switch or line breaker before inspecting or servicing the equipment.

(3) Lock switch OPEN (or rernoie line fuses) so that power cannot be turned on accidentally.

(4) Disconnect power to equipment if it is out of service.

(5) If troubleshooting must be done with the unit energized, have another person present who is trained in turning off the equipment and providing or calling for first aid.

2. Fire And Explosion Prevention

3.

4.

5.

Fire and explosion are caused by electrical short circuits, combustible material near engine exhaust piping, misuse of batteries and fuel, or unsafe operating or fueling conditions.

a. Electrical Short Circuits and Overloads

Overloaded or shorted equipment can become hot enough to cause fires by self destruction or by causing nearby combustibles to ignite. For electrically-powered equipment, provide primary input protection to remove short circuited or heavily overloaded equipment from the line.

b. Batteries

Batteries may explode and/or give off flammable hydrogen gas. Acid and arcing from a ruptured battery can cause fires and additional failures. When servicing, do not smoke, cause sparking, or use open flame near the battery.

c. Engine Fuel

Use only approved fuel container or fueling system. Fires and explosions can occur if the fuel tank is not grounded prior to or during fuel transfer. Shut unit DOWN before removing fuel tank cap. DO NOT completely fill tank, because heat from the equipment may cause fuel expansion overflow. Remove all spilled fuel IMMEDIATELY, including any that penetrates the unit. After clean-up, open equipment doors and blow fumes away with compressed air.

Toxic Fume Prevention Carbon monoxide - Engine exhaust fumes can kill and cause health problems. Pipe or vent the exhaust fumes to a suitable exhaust duct or outdoors. Never locate engine exhausts near intake ducts of air conditioners.

Bodily Injury Prevention Serious injury can result from contact with fans inside some equipment. Shut DOWN such equipment for inspection and routine maintenance. When equipment is in operation, use extreme care in doing necessary trouble-shooting and adjustment. Do not remove guards while equipment is operating.

Medical and First Aid Treatment First aid facilities and a qualified first aid person should be available for each shift for immediate treatment of all injury victims. Electric shock victims should be checked by a physician and taken to a hospital immediately if any abnormal signs are observed.

I t

Page ii Safety Instructions 910082 Sept l/90

Call physician immediately. Seek additional assistance. Use First Aid I techniques recommendedby American Red Cross until medical help arrives.

I ,/ I”, : i IF BREATHING’IS DIFFICULT, give oxygen, if available, and have victim lie

down. FCR ELECTRICAL SHOCK, turn off power. Remove victim; if not breathing, ‘begin artificial respiration, preferably mouth-to-mouth. If no detectable pulse, begin external heart massage. CALL EMERGENCY RESCUE SQUAD IMMEDIATELY.

6. Equipment Precautionary Labels Inspect all precautionary labels on the equipment monthly. Order and inspect all labels that cannot be easily read.

Safety Instructions 910092 Sept l/90

!

Page iii

This page intentionally let? blank,

I !

Page iv Safety Instructions 910082 Sept 190

TM-360

Exciter Armature Service Manual

l4omRr GROUND POWER

Service Manual for

Removal and Installation of

, Engine-Driven Generatpr Exciter Armatures i

I ‘1 i

Sectidn 1. General Information

1. General This section provides information and instructions for removal and installation of exciter armatures used on all current, and many older engine-drive generator sets. The name exciter armature refers to the shaft-mounted, revolving three-phase windings of the exciter. Hereafter, the name armature will refer to that revolving component of the exciter. The armature may, or may not, have a clutch mounting flywheel, and it may be a brushless type with built-in rectifier or it may be a brush type with built-in commutator.

Exciter armatures covered by the manual are mounted on the rear portion of the main generator armature shaft which extends rearward, beyond the rear generator bearing, into the exciter housing (See Fig. 1). Because of its location on the shaft, the exciter armature must be removed for rear main bearing replacement.

Since the removal and installation of exciter armatures can be rather complicated, this manual has been prepared to assist mechanics in the operation. It may be necessary to remove the exciter armature several times for bearing replacement during the life of a generator set.

Exciter armatures which are mounted ahead of the rear bearing and which do not require removal for bearing replacement are not covered by this manual.

2. Exciter Armature Most currently used exciter armatures consist of a revolving winding assembly, a rectifier assembly, and a one-piece flywheel and mounting sleeve (or hub) casting. (See Figure 2). The field core and rectifier are mounted on the sleeve of the flywheel casting. This type armature (with flywheel) allows the generator to be used in self-propelled units, or tractor/trailer-mounted units.

A few exciter armatures, which are used on truck/tractor/ and trailer units only, do not have a flywheel. Otherwise, they are similar to the armature shown in Fig. 2.

A third, older type armature is similar to the typical armature shown in Fig. 2, except the physical construction of the rectifier. Diodes in this rectifier are mounted in a straight line on two rectangular heat sinks, rather than on semi-circular heat sinks as illustrated in Fig. 2.

A fourth group of armatures are brush-type, in which the rectifier is replaced by a commutator.

Some generators use a remotely located static exciter (static voltage regulator) and therefore do not require a generator-mounted exciter. However, when these generators are used in self-propelled machines, they require a clutch mounting flywheel. Removal and installation of the flywheel is covered in the manual.

All exciter armatures (and clutch flywheels) are mounted on the main generator armature shaft with a machine key. On self-propelled machines, the armature is retained by the clutch and related mechanism. On truck, tractor, and trailer-mounted generators, the armature is held in place by a special retainer which is attached to the end of the shaft by a 1/2-i 3 hex head cap screw.

Figure 3 is an exploded view of a typical generator identifying components and their relative positions in the assembly.

January 31194 Page 1

TM-360

Exciter Armature Service Manual GROUND POWER

3. Exciter Armature Replacement

a. General

As stated earlier, exciter armature removal is often required for rear bearing replacement rather than for replacement of the exciter armature itself. Other reasons for exciter armature removal are: genera/or, armature replacement, general overhaul, etc.

b. Conditioh for Exciter Removh ’

The mechanics performing the work must decide upon the best and most convenient method of removing the exciter armature. On some units such as trailer and truck mounted generator sets, the armature is accessible without too much trou,ble; however, on self-propelled units, the drive shaft, transmission and clutch must be removed first.

If the exciter armature is being replaced, then the work may be performed without removing the generator from the machine. However, we believe that, in a great majority of cases, exciter removal will be for the replacement of bearings. This operation (bearing replacement) will require removal of the generator from the machine and major generator disassembly.

On self-propelled units especially, many mechanics prefer to remove the complete engine and generator assembly and then separate them. Others may prefer to remove the generator separately. We can only suggest that removing the engine and generator as an assembly may be the better way, because separating the engine and generator while they are installed in the unit is very difficult because of the limited working space on most machines.

c. Tools for Exciter Armature Removal and Installation

In addition to the standard mechanic’s hand tools such as wrenches, etc., you will need a gear puller with pilot plug and various sizes of puller attaching screws (l/2 - 13; 5116 - 1 8, and 318 - IS) depending upon the type armature or flywheel being removed. A typical gear puller is illustrated in Figure 4.

If only a single machine is being maintained, and the need for an installation tool would be very infrequent, a small lightweight sling-hammer puller may be sufficient. The sling-hammer puller (Fig. 3) is required for removing the threaded machine key (8, Fig.2) from the exciter armature. If the technician doesn’t have such a puller in his equipment, Figure 3 also shows components and dimensions for fabricating such a tool. Figure 4 shows a gear puller with pilot plug and puller attaching screws such as will be needed for pulling the exciter armature from the generator armature shaft.

To install an armature, in most cases, a fabricated tool for pushing the armature onto the generator shaft is required. The armature should NEVER be hammered onto the shalt. If only a single machine is being maintained, a a simple installation tool such as shown in Fig. 10 may be sufficient. If several machines are being maintained, it may be feasible to fabricate a tool which will make armature installation easier and faster. Figue 11 illustrates a typical tool of this type, and gives dimensions, materials, and instructions for fabricating such a tool.

d. How to Locate Information for Your Generator Set

If and when it becomes necessary to replace an exciter armature, the part number of the exciter armature will be needed so that this item may be ordered from Hobart Brothers Company. To order this item, proceed as follows.

(7) Determine the Specification Number of the generator set for which a replacement exciter armature is required. This specification number is stamped on an identification plate along with serial number, rating, etc. This identification plate is generally located on the control box.

(2) Refer to the Operation and Maintenance Manual that covers the specification number of the generator set for which the replacement exciter armature is required.

Page 2 January 31194

TM-360


HoBARr GROUND POWER

(3) Open the generator set manual to the Illustrated Parts List (Section 4-3 in current manuals, and Section 7-3 in older manuals). Turn to the Generator Assembly parts list and locate the exciter armature on the illustration and on the accompanying list of generator pa&Section 2. Exciter Armatures in Current Use

1. Exciter’Armatures With Clutch-Mounting Flywheels I (i

a. General \“I 1

Exciter armatures with clutch-mounting flywheels are currently used on most of Hobart’s engine- driven generator sets. Figure-‘1 shows the parts a typical generator and Figure 2 shows a typical exciter armature. Proceed as follows with removal and replacement of such armatures.

1. Armature shaft 9. Rear bearing snap ring

2. Flexible coupling and hub 10. Generator rear bearing 3. Flywheel adapter 11. Exciter stator 4. Engine flywheel 12. Exciter armature revolving fields 5. Fan 13. Rectifier

6. Front bearing 14. Exciter armature flywheel 7. Generator stator (clutch mounts here) 8. Generator revolving field 15. Armature locating snap ring

Generator (Top Half Sectioned) Figure 1

1


TM-360


HoBARr GROUND POWER

6 a 3

CROSS-SECTIONAL VIEW RECTIFIER END VIEW

I. Rotor windings 5. Negative heat sink

2. Rotor core 6. Leads routing holes

3. Positive heat sink 7. Rectifier

4. Diode 8. Threaded machine key

Exciter Armature Figure 2

b. Preparation for Exciter Armature Removal

(7) Remove exciter housing covers as required. If unit is not self-propelled, remove flanged retainer which holds armature on generator shaft. It is attached by a l/2-1 3 cap screw.

(2) Refer to Figure 9. Disconnect the two rectifier-to-generator field leads (1) from diodes (9) to which they are attached. Cut off terminal lugs (2) from the two leads so that leads will pass through routing holes in rectifier body and armature core as armature is removed. CUT AS CLOSE TO LUGS AS POSSIBLE to conserve leads and to prevent the need for splicing.

(3) Cut and remove tape (3) which binds generator field leads to armature sleeve. EXERCISE CARE to prevent damage to leads. Remove kinks in the two generator leads as much as possible before starting removal operation.

I


TM-360


HoBARr GROUND POWER

c. Exciter Armature Removal

(7) Removing the Threaded Key Wiih Sling-Hammer Puller (Figure 3)

Attachment of the assembled puller to the threaded key (8, Fig.2) in one operation is not recommended because the wbight and bulk of the assembly make threading the l/4-inch stud ihto the key rather clumsy. To do so could result in cross-threading and damage to the key and

1 stud. It is safer and easier fo ;attach as follows:

8. Thread stud (1, Fid 3) into adapter (2, Fig. 3) until it bottoms then thread this assembly (1) and (2) into key u&l stud bottoms in key threads. Tighten &cure/y.

s b. If hammer (5) and rod (4) are not a/read rod (4). Thread rod into adapter until it t!

assembled, thread one nut (3) onto adapter end of oitoms, then tighten nut secure/y against adapter.

Slide hammer (5) onto rod and install washer (6) and two nuts (3). Thread nuts onto rod until both nuts are fully threaded, then lock together.

Be very careful during removal process (slide-hammering) to avoid injury to

Exercise care to prevent breaking or damaging stud.

c SLING HAMMER(ASSEMBLED)

27/64 DRILL l-1/4" DEEP; TAP l/2-13,UNC-2B,l"DEEP

g3 10.2131 DRILL 1" DEEP;TAP l/4-28 UNF-2B. 3/4" DEEP . .' -

SLING HAMMER COMPONENTS

1. Stud, I/4-28 UNF 2A, grade 5 or 8 only 4. Rpd, l/2” round, CR steel 2. Adapter, 3/4” rolled CR steel 5. Hammer, 2” round CR steel 3. Nut, l/2-13 hex, steel (3 required) 6. Washer, flat, i/2”: steel

Sling-Hammer Puller Figure 3

1 !

January 31tQ4 Page 5

TM-360


c. Position hammer at adapter end of rod.

d. Quickly move hammer to outer end of rod with a rapjf, slinging motion. HOLD the hammer through the entire motion. If hammer is a/lowed to slide free on the rod, the stud could be DAMAGED or BROKEN.

e. Repeat steps (c) and (d) as required to loosen key, then remove key and slide hammer and Iput!e’. [“I 1

f. Affer key is removed, adply penetrating oil in the armature and shaf? keyways.

(2) Rempving the Armature with Gear Puller (See Figures 4 and 5)

Figure 5 shows the location of the holes into which gear puller screws must be inserted for removing the exciter armature from the generator armature shaft. This figure also shows the gear puller installed for pulling the ,exciter armature. Proceed as follows to remove the exciter armature.

a. Attach gear puller (Fig. 4) to the exciter armature using 6/16 - 18 puller attaching screws, just as shown . BE CERTAlN to install a plug in the end of the generator shal? to protect threads and pilot bushing.

b. AffaGh puller attaching screws so that pulling force is equally divided between them and so that the puller is mounted squarely.

c. Turn the main puller screw to apply pulling pressure. If the armature does not break loose, strike the end of the main puller screw with a heavy hammer. Continue to alternately tighten puller screw and strike the screw head until the armature breaks loose from the shaff.

d. when exciter armature is loosened, use the puller to remove it slowly from the shaft and at the same time observe the following CAUTION.

Pay close attention to field leads (1, Fig. 3) while pulling exciter armature from shaft. One mechanic should watch them constantly while another mechanic operates the puller. Make certain that leads do not catch and be sure that they slide smoothly through tubes (6, Fig. 3). Straighten leads and remove kinks to avoid damage to insulation.

-rl/ Pilot (A pilot MUST

be used to protect threads in end of

e3 shaft).

?- Attaching Screws

-Puller Screw

Typical Gear Puller Figure 4


TM-360


- GROUND POWER

Puller Mounting Holes (5116-16)

. Diode

Heat Sink

Field Leads Routing Holes

,Heat Sink

Exciter Armature With Puller Attached

Pulling the Exciter Armature Figure 5

1 !


TM-360


d. Installing the Exciter Armature

(7) Preparation for Exciter Armature Installation

a. Clean generator shaft, exciter qrnature bore, and machine key. Remove all rust, corrosion, etc,

b. ApFjy LOCQUIC primeq No. Clean excess from amratufe %

T+6 grade T to exciter armature key and keyway (See Fig. 6). oie mounting surface.

c. Apply LOCQUlC retaining compound, No. 40-31 to SIDES of machine key (See Fig. 7) and spread evenly. Remove excess LOCQUIC from shaff and key.

NOTE Manufacturers of recommended products are listed on the last page in this section.

d. Remove 3/8 inch of insulation from ends of revolving field leads (See Fig. 8) and attach a 2-foot length of small soi? wire to each. around lead by soldering.

Attachment may be made by wrapping wire tightly These wires are necessary to start and pull leads through routing

holes (6, Fig. 2) in armature core.

e. install armature locating snap ring (if used) on generator shafi.

NOTE: Application of LOCTITE is to compensate for any looseness in machine key and keyway (up to 0.005 inch).

Applying “Locquic” Primer Figure 6

0 !


Ex -

TM-360

titer Armature Service Manual

- GROUND POWER

Applying “Loctite” to Machine Key

Figure 7

(2) Exciter Armature Installation

Atter exciter armature has been prepared for installation according to preceding instructions, proceed with installation as follows:

a. Align armature keyway with keyway in annature shaff and start armature onto shai?.

b. R?ute the revolving field “pull” wit-es (installed in step 4 preceding) through routing holes (6, Fig. 2) and carefully pull leads into these routing holes. done.

Figure 9 shows how this should be

c. If the Fnnature-to-generator shaft fif is such that the armature may be pushed on by hand, push It on very slowly while another mechanic carefully watches and pulls the field leads fhmugh the routing holes. shoulder of the shafl).

Continue installation until armature core contacts the snap ring (or

If the armature cannot be pushed by hand, mount an installation tool on the generator shaft. (See Figures 10, 11, and 12). Push the armature on slowly and, at the same time, pull field leads through armature tubes. Stop pushing as soon as armature core contacts the shoulder of the shaft. Remove installation tools.

d. Route field leads through holes in rectifier base. terminals on field leads (See Fjg, 13).

Remove “pull” wires and clamp ring type Attach one lead to the nearest diode in the POSITIVE

group ?f three and attach the ofher lead to the nearest diode in the NEGATIVE group of three (SeeFig. 14). It makes no difference to which group of diodes (POSITIVE or NEGATIVE) a lead IS attached. The important thing is - DO NOT ATACH BOTH LEADS TO DIODES IN THE SAME GROUP. BE SURE ONE LEAD IS ATACHED TO THE POSITIVE GROUP AND THE OTHER TO THE NEGATIVE GROUP.

1 !


TM-360


- GROUND POWER

Do not use adhesive tape for securing leads. It may come loose and cause damage to exciter armature.

e. pen field leads are properly,8;qached to diodes, pull the excess lead back through the reckfier body so that anyllobsen&ss is between the rectifier and exciter armature windings. Press loose part of leads’ down against armature shaA between rectifier and excifer armature windings. Wrap 4 or 5 turns of linen tape around the armature shaff (See Fig. 15) to position and secure leads, Tie tape. ends together in a secure knot and cut off excess tape ends. Apply a coat of clear, air-drying varnish to the fape wrap. (See Fig.20).

f. Insert UNTHREADED end of machine key (8, Fjg. 2) in the keyway to tighten the exciter armature to the generator shafi; then tap it lightly until the fhreaded end of the key is flush with the end of the shaft.

g. Secure the excifer armature on generator shai? with the l/2-13 cap screw.

h. Install exciter housing cover.

i. install louvered exciter cover on end of canopy.

Allow at least 6 hours for complete cure and set up of Loctite before operating I machine. I

d ds

Generator Revolving Field Leads

Figure 8

Page IQ January 31l94

TM-360

Exciter Armature Sewice Manual

l+oBARr GROUND POWER

Pulling Generator Field Leads

Through Armature Figure 9

@ma biaxs j

l/2- inch Pipe

diameter

0 0

Threaded Rod, /

Washer, l/2-13 X 12 l/2- inch

hole inches long diameter

hole

Nut,

l/2-13

Simple Tool for Armature Installation Figure 10 ”


TM-360


HoBARr GROUND POWER

- 16 FULL HEX NUT

IA-13 HEX FULL NUT

1 l/4’ STANDARD BLACK STEEL PIPE 1

-------------------I

A- 34- 16 PLATE WASHERS 3~- 16 FULL HEX NUT

7 HARDEN TO ROCKWELL ‘C” 48-W

O.D.

Instructions for Making Exciter Armature Installation Tool

Figure 11 1


TM-360

Exciter Armature Service Manual l+oBARr GROUND POWER

Thread into end of Armature Shaft

7

Installation Tool in Installation Sequence

\

Pushing Armature onto Shaft with Special Tool

Figure 12

Attaching Field Lead Terminals Figure 13


TM-360


t .

Armature Retainer and Cap Screw

Knot

Tape

Armature Installed, Field Leads Attached, and

Armature Retainer Installed

Figure 14

Securing Leads to ShalI with Tape

Figure 215

i !


TM-360


HoBAlm GROUND POWER

Applying Varnish to Tape

Figure 16

5. Exciter Armature Without Clutch-Mounting Flywheels.

a. General

This paragraph covers an exciter armature that is very similar to those previously described, with the main exception that it does not have a clutch-mounting flywheel. It is shorter in overall length than the flywheel equipped armature and is used only on tractor or trailer mounted units driven by Detroit Diesel 3 and 4 cylinder engines (3-71 and 4-71). Removal and installation are exactly the same as those given for flywheel type armatures with the exception of one step in the removal procedure. Figure 17 shows a typical exciter armature without clutch-mounting flywheel.

b. Exciter Armature Removal

Exercise care to prevent breaking puller mounting screws or stripping thread in core.

Prepare for removal according to instructions given in Section 2, Paragraph 1, C, and attach puller in the same manner. Unlike the armatures previously described, this armature has 5116 - 18 tapped holes in the armature core to accommodate puller attaching screws instead of the l/2 - 13 size holes found on flywheel type armatures. one shown in Figure 5.

In appearance, this armature is otherwise the same as the

All other removal instructions are the same as given previously.

c. Preparation for Installation, and Installation.

Instructions for preparation for installation, and installation, are the same as those given in Section 2, Paragraph 1, D.

1


TM-360


HomRr GROUND POWER

Typical Exciter Armature Without Clutch-Mounting

Flywheel Figure 17

1 !

Page 16 January 31/94

TM-360


6. Removal and Installation Instructions for Improved Standard Production Exciter Armatures

a. Genkral

This paragraph provides updated removal and installation instructions for improved standard production exciter armatures and armature replacement kits first introduced in early 1975. These ihstr;uctions apply to rectif/er type! armatures (with and without flywheel) covered in Section 2 of this manual.

b. Improvement Changes

Improved armatures on production machines may be quickly identified by the change in the machine key used to attach them. To identify, observe the end of the armature, generator shaft, and machine key. The key used with improved armatures has as l/4 - 28 tapped hole in the outer end. Other changes, not apparent by observation, are a slightly enlarged armature bore and closer tolerance keyways.

These changes were made to reduce the difficulty of removal and installation while retaining a secure fit. The tapped hole in the machine key provides an attaching point for a “sling-hammer” puller to remove the key before removing the exciter armature, thus reducing some of the resistance encountered in exciter removal. Installation also becomes easier.

c. Exciter Armature Kits

Exciter armature kits for replacement are supplied with the new style threaded key and containers of LOCTITE, etc., recommended for use in installation.

d. Tool Requirements

A small, lightweight sling-hammer puller is required for removing the threaded machine key. You may have such a puller in your equipment. If not, Figure 3 also shows components and dimensions for fabricating such a tool. Sling-hammer pullers are commercially available.

e. Removal of Armature Attached by Threaded Key

Instructions differ from those in Paragraph 3, C only in the removal of the machine key. REFER TO MANUAL WHEN KEY IS REMOVED.

(7) Attach Sling-Hammer Puller

Attachment of the assembled puller to the threaded key (8, Fig.2) in one operation is not , recommended because the weight and bulk of the assembly make threading the i/4-inch stud

into the key rather clumsy. stud.

To do so could result in cross-threading and damage to the key and It is safer and easier to attach as follows:

(2) Thread stud (1, Fig. 3) into adapter (2, Fig. 3) until it bottoms, then thread this assembly (1) and (2) into key until stud bottoms in key threads. Tighten securely.

(3) If hammer (5) and rod (4) are not already assembled, thread one nut (3) onto adapter end of rod (4). Thread rod into adapter until it bottoms, then tighten nut securely against adapter. Slide hammer (5) onto rod and install washer (6) and two nuts (3). Thread nuts onto rod until both nuts are fully threaded, then lock together.

Exercise care to prevent breaking or damaging stud. I

January 31l94 Page 17

TM-360


Homlzr GROUND POWER

a.

b.

c.

Position hammer af adapter end of rod,

Quickly move hammer to outer end of rod with a rapid, slinging motion. HOLD the hammer through the entire motion. DAMAGED or BROKEN.

If hammer is allowed to slide free on the rod, the stud could be

Rebat steps (c) and (d) as required to loosen key, then remove key and slide hammer and Ipuller.

i t i I 1

(4) Loosen and Remove Exciter Armature

a. After key is removed, apply penefrating oil in the armature and shaft keyways,

b. Aftempt to loosen armature on shaff by rotating it slightly back and forth.

When armature is loosened, complete removal in accordance with instructions in Paragraphs 4 and 5 of this manual.

NOTE: If armature cannot be loosened by hand, use a puller according to directions in Paragraphs 4 and 5 of this manual.

f. Installation of Armature Attached by Threaded Key

(7) Clean generator shaff, exciter armature bore, and machine key thoroughly. Remove all rust, corrosion, oil, grease, etc.

(2) Apply LOCQUIC primer, No. 47-56 grade T to shaft and exciter keyways and to SIDES of machine key. Do not overprime. A thin film is best. Allow to dry three to four minutes.

(3) Apply a thin coating of LOCTITE No. 242 adhesive to SIDES of keyways in shaft and exciter armature BE CERTAIN to REMOVE any excess from mounting surfaces on shaft and bore of rotor.

NOTE: men armature removal is for the replacement of bearings and no Kit is involved, be sure that LOCTITE No. 242 is recommended. This is a milder adhesive than that recommended in the manual. When Kits are involved, the correct grade of LOCTITE is included in the Kit.

(4) The application of NEVER-SEE2 to the shaft and rotor bore is NOT recommended because there is a danger that it may mix with and contaminate the LOCTITE. Application of NEVER-SEE2 will be at the customer’s risk. LOCTITE can lose its adhesive and tightening properties if contaminated by rust preventatives, oil, or other lubricants and anti-rust products.

(5) Align keyways approximately and start rotor on shaft. REFER TO THE MANUAL, PARAGRAPHS 4 AND 5 FOR DETAILS REGARDING HANDLING OF LEADS, ETC. It is not likely that the installation tool will be required.

(6) Apply LOCTITE No. 242 adhesive to SIDES of new type threaded machine key. A thin film 0.005 to 0.010 inch thick is adequate and desirable.

(7) Align keyways in shaft and rotor. Insert UNTHREADED end of key in keyways, then tap lightly until threaded end is flush with end of shaft.

(8) Complete installation in accordance with instructions in manual.

Allow at least 6 hours for complete cure and set-up of LOCTITE before operating machine.


TM-360 .


t4oBAm GROUND POWER

Section 3. Exciter Armatures and Flywheels for Older Units

1. Flywht!fel Type Exciter +m@res With Rectifiers On Rectangular Bases

a. General

Section 3 applies to older style applies to older style, flywheel type exciter armatures (see Fig. 18) on which rectifier diodes are mounted on rectangular bases rather than on arc-shaped, semicircular bases presently used.

Revolving field leads are attached directly to the two diode bases rather than to diodes, and the armature core has only one tube for routing field leads. Figure 19 shows field lead attaching point.

Typical Exciter Armature with Diodes on Rectangular Bases Figure 18


TM-360


HoBARr GROUND POWER

I Y* Heat ISink

Lead Attachin Threaded Hale No. IO- 32

Exciter Armature Showing Field Lead

Attaching Point Figure 19

b. Preparation for Armature Removal

(7) Remove exciter housing cover.

(2) Remove screws which attach field leads to diode heat sinks (see Fig. 19). Cut terminal lugs from field lead. Cut as close to lugs as possible.

(3) Cut and remove tape (H, Fig. 20) which binds field leads to armature shaft. Remove kinks and straighten field leads as much as possible so that they will slide freely through core tube (B, Fig. 20) when armature is removed.

c. Exciter Armature Removal

Follow removal instructions in Section 2.

d. Preparation for Armature Installation

Prepare armature for installation according to instructions in Section 2.

e. Installation

(7) Align armature keyway with key in shaft and start armature on shaft.

(2) Route revolving field leads “pull” wires through the single tube in armature and carefully pull leads into tube.

(3) If the armature-to-generator shaft fit is such that the armature may be pushed on by hand, push it on very slowly while another mechanic carefully watches and pulls field leads (A, Fig. 20) through tube (B). Continue installation until armature core contacts snap ring (or shoulder).

If the armature cannot be pushed on by hand, mount an installation tool on the generator shaft. Special tools for installation are illustrated in Figures 5 and 6. W&h the tools illustrated in Fig. 6, an impact wrench may be used to push the armature onto the shalt. Push the armature on slowly and, at the same time, pull field leads through armature tube (B, Fig. 20). Stop pushing as soon as armature core contacts locating ring (or shoulder). Remove installation tools.

I !


TM-360


F E G

A. Generator field leads B. Field leads routing tube C. Exciter armature windings D. Flywheel

E. Diode mounting bracket (heat sink) F. Field leads attaching point G. Diode H. Tape

Exciter Armature Removal/Installation Details Figure 20

(4) Draw field leads tight through armature tube. Remove “pull” wires and attach ring type terminals on field leads (see Fig. 13). Use lo-32 machine screws and lockwashers to attach field leads to terminals on each of the two heat sinks. It makes no difference to which heat sink a lead is attached.

Do not use adhesive tape to secure leads. It may come loose and cause I damage to the exciter armature. I

L !


0

TM-360


(5) When field leads are properly attached to heat sinks, press loose parts of leads down against armature shaft between rectifier and armature windings, and secure with linen tape (see Fig. 19). Wrap 4 or 5 turns of tape around the armature shaft to position and hold leads. When tape is wrapped and knotted, cut off loose, ends. Apply a coat of clear, air-drying varnish to the wrapping (see Fig. 20).

2. Brush-Tiyp#, Flywheel-Equippe,d firmature With Commutator i (

a. General

This paragraph covers a flywheel equipped exciter armature (Fig. 21) which may be used on all types (trailer-mounted, self-propelled, etc.) of older ground power units.

Armatures covered in the previous paragraphs have been rectifier types. The armature covered here is a brush type, having a commutator located where the rectifier is normally mounted.

This type armature is easier to remove and replace because revolving field leads are not a problem.

b. Preparation for Armature Removal

(1) Remove exciter housing cover(s) as required. If the unit is NOT self-propelled, remove flanged retainer which holds armature on generator shaft. Retainer is attached by a l/2 - 13 cap screw.

(2) Remove exciter brushes from brushholder, or lift and wedge them at a height sufficient to clear windings when armature is removed. 1

l- Exciter Rotor Windings

Commutator

-Flywheel

Typical Brush Type Exciter Armature

Figure 21


TM-360


l4omIzr GROUND POWER

c. Armature Removal

(7) Attach a puller to the armature flywheel using l/Z - 13 puller attaching screws (see Fig. 10). BE CERTAIN to install a plug in the end of the generator shaft to protect the threads.

(2) Adjust puller attaching screws’s0 that pulling force is equally divided between them and the , putler is mounted squarely. ,;

(3) T&n the main puller screi to apply pulling pressure. If the armature does not break loose, strike the end of the main puller screw with a tieavy hammer. Continue to alternately tighten puller screw and strike the screw head until the armature breaks loose from the shaft.

Exercise extreme care to prevent breaking the flywheel. If the flywheel is broken, it may be necessary to cut the armature from the shaft.

(4) When armature is loosened, use the puller to remove it from the shaft. Make certain that brushes will clear the armature windings.

(5) Remove machine key from shaft. Remove puller from armature.

d. Preparation for Armature Installation

(7) Clean generator shaft, exciter annature bore, and machine key. Remove all rust, corrosion, etc.

(2) Apply “Locquic” primer Grade T, No. 47-56 to exciter armature key and keyway (see Fig. 11). Clean excess from armature bore mounting surface.

(3) Apply “Loctiie” retaining compound, No. 40-31 to SIDES of machine key (see Fig. 12) and spread evenly. Install key in generator shaft and secure with spring pin (if used). Remove excess “Loctite” from shaft and key.

(4) Install armature locating snap ring on generator shaft (if used).

e. Armature Installation

After exciter armature has been prepared for installation according to instructions above, proceed with installation as follows:

(7) Align armature keyway with key in shaft and start armature on shaft. Make certain that brushes 1 are removed from brushholders, or are wedged in holders so that they will not interfere with

armature installation.

(2) If armature-to-generator shaft fit is such that the armature may be pushed on by hand, push it on carefully until it contacts the snap ring (or shoulder).

If the armature cannot be pushed on by hand, mount an installation tool on the generator shaft. Special tools for installation are illustrated in Figures 5 and 6. With the tools illustrated in Fig. 6, an impact wrench may be used to push the armature onto the shaft. Push the armature on slowly until it contacts the snap ring.

(3) Remove installation tool. If the generator is NOT used in a self-propelled unit, secure the armature on generator shaft with a flanged retainer and l/2 - 13 cap screw.

1 !


TM-360


3. ClutcNVlounting Flywheel for Static Excited Units

a. General

This paragraph applies to self-propelled units which are static-excited. They do not have a generator-mounted exciter, but are excited by a remotely located static voltage regulator. However, they d bearin 13

have a clutch-mounting flywheel (see Fig. 27) which must be removed for generator rear replacement. The flywheel ~s’a one-piece iron casting, consisting of the flywheel and hub

which is approximately 4- l/2 inches long.

b. Preparation for Flywheel Remowal

No special preparation is required for removal of the flywheel.

c. Flywheel Removal

(1) Attach a puller to the flywheel using 3/8 - 16 puller attaching screws (see Fig. 10). BE CERTAIN to install a plug in the end of the generator shaft to protect the threads

(2) Adjust puller attaching screws so that pulling force is equally divided between them and the puller is mounted squarely.

(3) Turn the main puller screw to apply pulling pressure. If the flywheel does not break loose, strike the end of the main puller screw with a heavy hammer. Continue to alternately tighten puller screw and strike the screw head until the flywheel breaks loose from the shaft.

Exercise extreme care to prevent breaking the flywheel. If the Rywheel is broken, it may be necessary to cut it from the shaft.

(4) When flywheel is loosened, use the puller to remove it from the shaft.

(5’ Remove machine key from shaft. Remove puller from flywheel.

d. Preparation for Flywheel Installation

(7) Clean generator shaft, flywheel hub bore, and machine key. Remove all rust, corrosion, etc.

(2) Apply “Locquic” primer Grade T, No. 47-56 to exciter flywheel key and keyway. Clean excess from hub bore mounting surface.

(3) Apply “Loctiie” retaining compound, No. 40-31 to SIDES of machine key (see Fig. 12) and spread evenly. Install key in generator shaft and secure with spring pin (if used). Remove excess “Loctite” from shaft and key.

(4) Install flywheel locating snap ring on generator shaft (if used).

e. Flywheel Installation


(7) Align armature keyway with key in shaft and start flywheel on shaft.

(2) If flywheel-to-generator shalt ffi is such that the flywheel may be pushed on by hand, push it on carefully until it contacts the snap ring (or shoulder). ”

If the armature cannot be pushed on by hand, mount an installation tool on the generator shaft. Special tools for installation are illustrated in Figures 5 and 6. With the tools illustrated in Fig. 6, an impact wrench may be used to push the flywheel onto the shaft. Push the flywheel on slowly. until it contacts the snap ring (or shoulder)..

(3) Remove installation tool.

1 !


TM-360


l4omRr GROUND POWER

Exercise extreme care to prevent breaking the flywheel. If the flywheel is broken, it may be ‘necessary to cut it from the shaft.

(4J qen flywheel is loosened, use the puller to ‘remove it from the shaft.

(5) Remove machine key from shaft. Remove puller from flywheel.

d. Preparation for Flywheel ln$tallation

(7) Clean generator shaft, flywheel hub bore, and machine key. Remove all rust, corrosion, etc.

(2) Apply “Locquic” primer Grade T, No. 47-56 to exciter flywheel key and keyway. Clean excess from hub bore mounting surface.

(3) Apply “Loctite” retaining compound, No. 40-31 to SIDES of machine key (see Fig. 12) and spread evenly. Install key in generator shaft and secure with spring pin (if used). Remove excess “Loctite” from shaft and key.

(4) Install flywheel locating snap ring on generator shalt (if used).



(7) Align armature keyway with key in shaft and start flywheel on shatt.

(2) If flywheel-to-generator shaft fit is such that the flywheel may be pushed on by hand, push it on carefully until it contacts the snap ring (or shoulder).

If the armature cannot be pushed on by hand, mount an installation tool on the generator shaft. Special tools for installation are illustrated in Figures 5 and 6. With the tools illustrated in Fig. 6, an impact wrench may be used to push the flywheel onto the shaft. Push the flywheel on slowly until it contacts the snap ring (or shoulder).

(3) Remove installation tool.

4. Clutch-Mounting Flywheel: Static Excited Units, Attached by Setscrews

a. General

This paragraph, like the preceding paragraph, applies to self-propelled, static-excited units equipped with a bare clutch mounting flywheel (see Fig. 23). However the flywheel for this group does not have puller attaching tapped holes. It also is the only flywheel which is attached by setscrews.

b. Preparation for Flywheel Removal

The flywheel attaching setscrews should be removed and penetrating oil should be applied through tapped holes several hours before actual removal. Also apply oil at both ends of flywheel hub.

c. Flywheel Removal

(71 Attempt to loosen the flywheel by striking it with a rawhide or similar hammer, or a heavy hammer used with a heavy brass rod.

(2) If the flywheel cannot be removed by driving it off, it is suggested that puller attaching holes be drilled and tapped in the flywheel. The puller tool body may be used as a template. Drill 27/64” holes and tap them for l/2-13” screws. Attach puller and pull flywheel off shaft.


TM-360


Clutch-Mounting Flywheel with Setscrews Figure 23

(3) If the installation is rusted and corroded so badly that the flywheel cannot be removed, the last resort is to break or cut it from the shag. Since the flywheel is made of cast iron, it may be broken or cut fairly easily.

d. Preparation for Flywheel Installation

Prepare the flywheel and generator shaft the same as instructed in Paragraph 9.


Flywheel installation is the same as described in Section 2, Paragraph 3, except that, after it is properly positioned, install two setscrews and tighten securely.


TM-360


HoBARr GROUND POWER

Recommended Products Manufacturers

“LOCQUIC” No. 47-56, Primer Grade T, Manufactured by Loctite Corporation, Newington, Connecticut 06111 ,/* ‘1,

“LOCTITk” No. 40-31, Retaining Compound, Manufactured by Loctite Corporation, Newington, Connecticut 0611 I

“NOCOdO” Varnish No. T-21 1 (clear, air dry), Manufactured by Sterling Division of Reichhold Chemical Incorporated, Marysville, Pennsylvania 17053


TM-360


This page intentionally let7 blank.

I I

!


Documents

TM-360 l+oBARr”TM-360 Exciter Armature Service Manual GROUND POWER 3. Exciter Armature Replacement a. General As stated earlier, exciter armature removal is often required for rear