TM 5-6115-423-15D E P A R T M E N T O f T H E A R M Y T E C H N I C A L M A N U A L

OPERATOR, ORGANIZATIONAL, DIRECT AND GENERALSUPPORT AND DEPOT MAINTENANCE MANUAL

LOAD BANK, 0-30 KW; AC; PORTABLE, SKID-MOUNTED(SUN ELECTRIC CORP MODEL GPT-3D-1)

FSN 6115-964-1091 AND (SUN ELECTRIC CORP MODELGPT-3D) FSN 6115-903-8174

This copy is a reprint which includes currentpages from Change 1.

H E A D Q U A R T E R S , D E P A R T M E N T O F T H E A R M Y

AUGUST 1967

SAFETY PRECAUTIONS

BEFORE OPERATION

Ground the Load Bank frame to avoid shock hazard. Ground stud is located on the housing justbelow the control panel.

DURING OPERATION

Never remove panels on the Load Bank without first disconnecting the unit from the powersource.

Do not connect, disconnect or touch electrical leads or parts until unit is shutdown.If excessive vibration or unusual noises occur turn off the unitUse CO2, not water in putting out an electrical fire.If motor or other components heat up excessively, stop the Load Bank at once.

If Selenium rectifier has failed or is burning (accompanid by acrid stench), de-energize LoadBank at once and remove to outside to dissipate fumes.

AFTER OPERATION

Never use or store the unit in an upside down or on end position.

CHANGE

No. 1 }T M 5 - 6 1 1 5 4 2 3 - 1 5

C 1

HEADQUARTERSDEPARTMENT OF THE ARMYW ASHINGTON , DC, 17 May 1973

O p e r a t o r , O r g a n i z a t i o n a l , D i r e c t S u p p o r t ,Genera l Suppor t and Depot Ma in tenance Manua l

LOAD BANK, 0-30 KW; AC; PORTABLE, SKID-MOUNTED(SUN ELECTRIC CORP. MODEL GPT-3D-1)

FSN 6115-964-1091 AND (SUN ELECTRIC CORP MODELG P T - 3 D ) F S N 6 1 1 5 - 9 0 3 - 8 1 7 4

TM 5-6115-423-15, 10 August 1967, is changed as Page 3. Paragraph lb, the third sentence isfollows: deleted. Appendix C contains *** of this

equipment”.

The title is changed to read as shown above. Page 49. Appendix A is superseded as follows:

APPENDIX AREFERENCES

A - 1 . P a i n t i n g

AR 746-1

A - 2 . M a i n t e n a n c e

FM 29-2

TM 5-764

TM 11-483

TM 38-750

TM 5-6115-423-25P

Color, Marking and Prep-a r a t i o n o f Equip-ment for Shipment

Organizational Mainte-nance Management

Electric Motor and Gen-erator Repair

Radio Interference SU P

pression

The Army MaintenanceManagement System(TAMMS)

Organizational, Direct andGeneral Support, andDepot Maintenance Re-pair Parts and Spe-cial Tools Lists; had

A - 3 . S h i p m e n tS t o r a g e

TB 740-97-2

TM 740-90-1

A - 4 . D e m o l i t i o n

TM 750-244-3

Bank 0-30 KW AC,Portable, Skit Mounted(Sun Electric CorpModel GPT-3D-I ) FSN6115-964-1091 and (Mod-el GPT-3D) FSN 6115903-6174

a n d

Preservation of USAFE-COM MechanicalEquipment for Storage

Administrative Storage ofEquipment

Procedures for Destruc-tion of Equipment toPrevent Enemy Use

1

Page 55. Appendix C is superseded as follows:

APPENDIX C

BASIC ISSUE ITEMS LIST AND ITEMSTROOP INSTALLED OR AUTHORIZED

Section 1. INTRODUCTION

C-1. Scope a. Source,

This appendix lists items required by the operator Code (SMR).for operation of the load bank. b. Federal

AUTHORIZED

Maintenance and RecoverabilityNot applicable.

Stock Number. This column

C-2. GeneralThis list is divided into the following sections:

a. Basic Issue Items List — Section II. Notapplicable.

b. Items Troop Installed or Authorized List —Section III. A list of items in alphabeticalsequence, which at the discretion of the unit com-mander may accompany the load bank. Theseitems are NOT SUBJECT TO TURN-IN with theload bank when evacuated.

indicates the Federal stock number assigned tothe item and will be used for requisitioning pur-poses.

c. Description. This column indicates theFederal item name and any additional descriptionof the item required.

d. Unit of Measure (U/M). A two-characteralphabetic abbreviation indicating the amount orquanity quantity of the item upon which theallowances are based, e. g., ft, ea, pr, etc.

e. Quantity Furnished with Equipment (BIIL),C4. Explanation of Columns Not applicable.

The following provides an explanation of columns f. Quantity Authorized (Items Troop In-in the tabular list of Basic Issue Items List, Section stalled or Authorized). This column indicatesII, and Items Troop Installed or Authorized, the quantity of the item authorized to be usedSection III. with the equipment.

2

By Order of the Secretary of the Army:

Official:VERNE L. BOWERSMajor General, United States ArmyThe Adjutant General

CREIGHTON W. ABRAMSGeneral, United States ArmyChief of Staff

Distribution:

To be distributed in accordance with DA Form 12-25D, Operator requirements for Generator Sets,30 KW, 60 HZ Precise Power and 30 KW, 400 HZ Precise Power.

3

TM 5-6115423-15

T ECHNICAL M A N U A L HEADQUARTERSDEPARTMENT OF THE ARMY

No. 5–6115423-15 W ASHINGTON , D. C., 10 August 1967}Operator, Organizational, Direct And General Support

And Depot Maintenance Manual

LOAD BANK, 0-30 KW; AC; PORTABLE, SKID-MOUNTED(SUN ELECTRIC CORP MODEL GPT-3D-1) FSN 6115-964-1091

C H A P T E R 1.

Sec t ion I .IL

C H A P T E R 2 .

Sec t i on I .II.

III.IV.

C H A P T E R 3 .

Sec t ion I .II.

III.I v .v .

VI.

C H A P T E R 4 .

Section 1.

C H A P T E R 5 .

3-5

Sec t ion I .II.

C H A P T E R 6 .

Sec t ion I .II.

III.

C H A P T E R 7 .

Section 1.II.

III.IV.

v .VI.

VII.

A P P E N D I X A .

B.

c.

AND (SUN ELECTRIC CORP MODEL GPT-3D)FSN 6115-903-8174

Paragraph

INTRODUCTIONGeneral ------------------------------------------------------------------- 1,2Descriptlon and data -------------------------------------------------------INSTALLATION AND OPERATING INSTRUCTIONSService upon receipt of equipment ------------------------------------------ 6-10Movement to new worksite ------------------------------------------------- 11-12Controls and lnstruments -------------------------------------------------- 13,24Operation of equipment --------------------------------------------------- 15-24OPERATOR AND ORGANIZATIONAL MAINTENANCE INSTRUCTIONSSpecial tools and equipment ------------------------------------------------ 25-27Lubrication-------------------------------------------------------------------------------------- 28,29Preventive malntenance services------------------------------------------------------------------30-32Operator maintenance------------------------------------------------------------------------------33-42T r o u b l e s h o o t i n g - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4 3 - 4 9Radio Interference suppression ------------------------------------------------------------------50-53DEMOLITIONOF EQUIPMENTDemolition of load bank to prevent enemy use -------------------------------- 54-58DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT

MAINTENANCE INSTRUCTIONSGeneral ------------------------------------------------------------------- ----------------------------59,60Description and data ----------------------------------------------------- 61,62GENERAL MAINTENANCE INSTRUCTIONSSpecial tools.and equipment------------------------------------------------------------------------63,64Trouble shootlng--- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -----------------65-70Removal and installation of major components ------------------------------- 71-78REPAIR INSTRUCTIONSRepair of variable transformer --------------------------------------------79,80Repair of auto transformer-----------------------------------------------------------------------------81,82Repair of rectlfler -------------------------------------------------------- 83,84Repair of replay --------------------------------------------------------- 85,86Repair of contactor -------------------------------------------------------- 87,88Repair of power absorber -------------------------------------------------- 89,90Repair of control transformer--------------------------------------------------------------91,92

Page

33-9

11-1212-13

1314–17

1919

19-3222-2424-2525-26

27

2929-30

3131

31-38

3939

39-404040

40-4141-48

-- 49REFERENCES --------------------------------------------------------------------MAINTENANCE ALLOCATION CHART --------------------------------------------- 5 1BASIC ISSUE ITEMS LIST --------------------------------------------------------- 5 5

I N D E X - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5 9

1

TM 5-6115-423-15

CHAPTER 1

INTRODUCTION

Section 1.

1. scope

a. These instructions are published for useby personnel to whom the load bank isissued. Chapters 1 through 4 provide infor-mation on operation, preventive maintenanceservices, and organizational maintenance ofequipment, accessories, components and attachm-ents. Also, included are instructions for de-stroying the equipment to prevent capture byan enemy. Chapter 5 through 7 provides infor-mation for direct, general support, and depotmaintenance. Included are descriptions of mainunits and their functions in relationship toother components.

b. Appendix A contains a list of publica-tions applicable to this manual. Appendix Bcontains the maintenance allocation chart. Ap-pendix C contains a list of basic issue itemsauthorized by the operator of this equipmentThe organizational, direct and general supportand depot maintenance repair parts and specialtools are listed in TM5-6115-423-25P.

c. Numbers in parentheses following nomen-c la ture ca l l ou t s on i l lu s t ra t ions ind ica te

GENERAL

quantity; numbers preceding nomenclaturecallouts indicate preferred maintenance se-quence.

d. DA Form 2028 (Recommended Changesto DA Publication) will be used for report-ing discrepancies and recommendations for im-proving this equipment publication. Thisform will be completed by the individual usingthe manual and forwarded direct to Command-ing General, U.S. Army Mobility EquipmentCommand, ATTN: AMSME–MP, 4300 Good-fellow Blvd., St. Louis, Mo. 63120.

e. Report all equipment improvement recom-mendations as prescribed by TM 38–750.

2. Record and Report Forms

a. DA Form 2258 ( Depreservation Guide forVehicles and Equipment).

b. For other record and report forms appli-cable to operator, crew and organizational main-tenance refer to TM 38-750.

Note. Applicable forms, excluding Standard Form 46(United States Government Motor Vehicle Operator’sidentification card) which is carried by the operatorshall be kept in a canvas bag mounted on the equipment.

Section Il. DESCRIPTION AND DATA

3. Description generating equipment. Testing is accomplish-

a. General. The Sun Electric Corp., LoadBank, Model GPT–3D–1 is a portable skidmounted test unit fully self-contained andmounted within a welded steel, weather tightcabinet built integrally into a welded steelchassis.

b. Purpose. The load bank (fig. 1) functionsas a loading and testing device for electrical

ed by applying to the generating equipment,resistive loads in increments. They can bemanipulated in various combinations to simu-late any resistive electrical load within theload bank rating, The load bank itself gener-ates no power. Its operation is entirely depend-ent upon external power sources, and operatesthrough the system to which it is connectedand must test. Loading characteristics may be

3

TM 5-6115-423-15

Figure 1.

Thus the capabilitiesset up and controlled.of the power generating equipment to performunder these conditions can be tested andmeasured. The load bank is designed to testthe output characteristics of generating plantsrated 120/208 and 240/416 volts three phase4-wire; 240-volts three phase 3-wire; 120 or240 volts single phase 2-wire. Tests can beapplied at frequencies between 50 and 1000cycles per second. Power cables connecting theload bank and the equipment to be tested

are connected to the terminal strip adjacent tothe control panel. Cables are not furnishedwith the equipment.

(1) The load bank has a 3, 6 and two9 kilowatt switches by which it canapply any fixed load in incrementsof 3 up to 27 kilowatts. It can applyvariable loads 0.5 to 3 kilowatts atfrequencies between 50 and 1000cycles per second.

4

(2)

TM 5-6115423-15

When fixed and variable loads are encloses all components is made upapplied in combination, the load bank of an integral welded steel frame andcan apply any load from 0.5 t, 30 housing. Removable top and sidekilowatts on either single or balanced panels allow access to the cabinet in-three phase operation. terior for service, maintenance and in-

c. Major Assemblies and Components. Themajor assemblies and components of the loadbank includes a cabinet and cabinet assembly,control panel assembly, power absorbers, vari-able transformer, contactor, rectifier, terminalstrip, and relay. Major components of the loadbank are illustrated in figures 1 through 4.

(1) Cabinet and cabinet assembly. Thecabinet assembly which completely

spection. A hinged drop door protectsthe controls and can be swung backto assure access to controls. On theback a hinged metal door portects anexpanded metal ventilating panel.The load bank is ventilated and heatdissipated through the expandedmetal. Latches secure the doors to as-sure protection during storage and

Figure 2. Load bank, left rear, three-quarter view.

5

TM 5-6115-423-15

(2 )

(3 )

shipment. Carry handles welded atthe top of the cabinet permit carryingthe unit. A fork lift tong, inserted be-tween four corner feet can be used totransport the unit for a short dis-tance, Feet which support the loadbank 2 1/4-inches off the ground willaccept tie rods, cables or lashing suit-able for fastening the unit to a skid,pallet or trailer.Control panel assembly. Located onthe recessed control panel (fig. 2)are a toggle type master switch, fivetoggle load switches, and one vari-able load control knob. They provideall necessary controls for test to whichthe load bank is applied. The loadincrements identifying each controlare indicated by identification plateslocated on the face of the controlpanel.Power absorbers, Three duct-type 10kilowatt power absorbers (figure 3)

provide necessary resistive loads. Re-sistive elements are made of 1/8inch-corrugated nichrome ribbon en-closed within a slotted housing. Fanmotors (part of connected load) coolthe absorbers by circulating air drawnthrough openings in the cabinet andforcing it out through venting doors.Resistive elements can withstandsurface temperatures over 1000°F.Restriction of intake cooling air willcause rapid temperature rise and resuit in drop of load. Air flow vaneis pivoted on a shaft on each powerabsorber so that impact of cooling airactuates a switch which remains closedas long as air flows through. If airflow stops, it cuts off load. The ther-mal overload shall cause the load buscontractors to drop load in the eventthat temperatures in excess of 248°Fdevelop in the resistive module. Iftemperature overload occurs, it will

Figure 3. Load bank front view, front access panel removed.

6

( 4 )

(5)

(6)

reset automatically after resistive ele-ments cool down.Variable transformer. The three-gangvariable transformer (fig. 4) provideschangeable control of load from 0 to3 KW. It is operated manually by avariable control knob located on thecontrol panel. With the variable loadswitch and the variable control knob,the variable transformer controlsloads from 0.5 KW to 3 KW onsingle phase or balanced 3-phase op-eration. Therefore, using a combina-tion of the fixed load switches andthe variable load control, loads from0.5 KW to 30 KW may be provided.Contactor. A 3 PST (Pole Singlethrew) 200 ampere, 200 volt AC;400 cycle 28 VDC coil contactor (fig.4) incorporated into the circuitrymakes and breaks applied loads as setUp by increment or air-flow switches.Rectifier. The rectifier (fig. 3) con-verts the line voltage to a nominal

(7)

(8)

(9)

TM 5-6115-423-15

28 volts DC at 10 amperes for opera-tion of the power absorber fan motors.Terminal strip. Four terminal studs(L 1, L2, L3, and Lo) with 3/8-24threads and bakelite connecting knob,are located on the terminal strip (fig.2) which is located at the back ofthe load bank, Two copper shortinglinks tie terminals together for singlephase operation.Relay. The relay (fig. 4) with 150volt minimum, 200 volt maximumpull-in, operates over a frequencyrange of 50-1000 cps (cycles persecond). It senses the input power ofthe source as determined by connec-tion to terminal strip TB1,Auto transformers. The auto trans-formers are only in use when theload bank is used for high voltage(240/416 VAC). They reduce thehigh voltage to low voltage so thesame components can be used regard-less of whether the load bavnk is used.

VARIABLETRANSFORMER

Figure 4. Load bank, top view, cover removed.

7

TM 5-6115-423-15

for high or low voltage.(10) Control transformers. The control

transformers reduce the 120 VAC tonominal 28-volts. This voltage thengoes to the rectifiers.

4. Identification and Tabulated Dataa. Identification. The load bank has 12

major identification plates. The informationcontained on these plates is listed below.

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

8

Corps of engineers identificationplate. The plate identifying corps ofengineers U.S. Army Data is attachedto the right side of the load bankcase. It lists serial number, contractnumber, stock number, modelnumber, shipping weight and otherpertinent unit data.Company plate. The plate is locatedjust below the corps of engineersidentification plate. It lists SunElectric Corporation part number,model number, stock number andcontact number as well as the ratingof the load bank.Ground plate. The plate (fig. 2) isattached to the cabinet below and tothe left of the control panel and di-rectly below the ground connection.Input selector plate. The input selec-tor identification plate (fig. 2) isattached to the baffle assembly in theback of the unit. It identified theconnector plug connations.High voltage connector plate. Thisplate (fig. 2) is attached to the baffleassembly at the rear of the load bank.It identifies high voltage connectorreceptacle, JIB.Low voltage connector plate. Thisplate (fig. 2) is attached to the baffleassembly at the rear of the load bank.It identifies the low voltage connectorreceptacle, J1A.Terminal plate. The terminal identi-fication plate (fig. 8) is located onthe baffle to the right of the terminalstrip TB1. It identifies terminals L1,L2, L3 and L0.Instuction plate, The plate with op-erating instructions is attached to the

(9)

(lo)

(11)

(12)

control panel door on the left wallof the case, It explains the operatingprocedure and automatic safety de-vices and shows connections forvarious load voltages.Schematic plate. The electrical sche-matic plate (fig. 2) is attached to theinside face of the air exhaust door atthe back of the load bank. It illus-trates complete unit w-i ring.Load switch plate. The plate identi-fying the load switches (fig. 7) isattached to the control panel on theleft of the load bank. The plate indi-cates load increments applied by eachload toggle switch.Master switch plate. The plate identi-fying the master switch (fig. 7) is lo-cated on the control panel directlyabove the load switch plate.Variable load control plate. The plateidentifying variable load control (fig.7) is located to the right of the loadswitch plate. An arrow indicates aclockwise turn of the variable loadcontrol knob necessary to increasethe load.

b. Tabuluted Data.(1) Load bank.

Manufacturer___________________Sun Electric Corp.Model_______________________GPT-3D-1Type--__________________Portable skid mounted,

self containedPower____________________From connected power

plant

elements. Fan cooledwith thermal overload

(3) Rectifier.

TM 5-6115-423-15

(12) Wiring diagram. Refer to figure 5for the practical wiring diagram.

(13) Base plan. Refer to figure 6 for thebase plan.

5. Difference in Models

This manual covers the Sun Electric Corp.models GPT-3D and GPT-3D-1, load bank,0–30 KW, AC. The difference in models isthat several parts used is the two models arenot interchangeable. Refer to TM 5-6115-423-25P for the correct part used. Also, modelGPT–3D is physically slightly smaller thanmodel GPT–3D-1.

Figure 5. Practical wiring diagram.

(Located in back of manual)

9

TM 5-6115-423-15

Figure 6. Base plan.

1 0

TM 5-6115-423-15

CHAPTER 2

INSTALLATION AND OPERATING INSTRUCTIONS

Section 1. SERVICE UPON RECEIPT OF EQUIPMENT

6. Unloading the Equipment

The load bank is shipped completely assem-bled enclosed in a wooden crate with blockingsupports that prevent shifting during transit.The base of the crate is raised to allow tongsof a fork lift to be inserted in order to movethe load bank to site of operation or to storage.

7. Unpacking the Equipment

Remove top, sides, and ends of the crateand strip away weather resistant protectivewrapping. Remove the cushioning packingmaterial from cabinet interior and the dessi-cants placed to remove moisture in transit.In uncrating, not indication of damage to crateor to equipment. Strip away pressure-sensitivetape over doors and openings. Remove hexa-gon head bolts and flat washers that securethe base to the load bank.

8. Inspecting and Servicing

Warning: Do not connect the Load Bank topower source and energize until initial inspec-tion procedures have been carried out.

a. Following the unpacking of the loadbank, inspect the equipment making the follow-ing checks:

(1)

(2)

(3)

(4)

Check chassis and cabinet for indica-tions of possible damage.Check interior components for in-transit damage.Check wiring and posts for loose con-nections.Brush or wipe away dust or other im-purities on the power absorbers, vari-able transformer, rectifier assembly

and other electrical parts where dustmight interfere with operation.

(5) Look over switches and other interiorcomponents for security of mounting.Be sure the variable control knobturns as indicated and that trans-former components move as knob isturned.

b. Refer to paragraph 31 for daily preven-tive maintenance service.

9. Installation of Separately PackedComponents

The load bank is shipped as a completelyself-contained unit. No installation of sepa-rately packed components is required.

10. Installation or Setting-Up Instructions

a. Location. Select an area that will insurefree circulation of air around the unit andwith sufficient working area for operating andservicing. Front access panel and air exhaustdoor are easily removed for servicing. Allowadequate space for opening doors.

Caution: Allow a minimum of 25 feet separa-tion from fuel storage, combustible or volatilematerials. Operate in an area free from ob-structions, with sufficient space for openingdoors and gaining access to components foroperating and servicing.

b. Outdoor Installation. Protection againstinclement weather and temperature extremesshould be considered. Need for a shelter willbe dictated by temperature, dust and climaticconditions. Use of a tarpulin or cover whenthe load bank is not in use is recommended,

11

TM 5-6115-423-15

Figure 7. Controls and instruments-control panel.

When exposed to high mositure conditions ation either on its own base or secured toparticularity in warm climates, components pallet, trailer, or skid. It is advisable to setsuch as fan motors, selenium rectifiers, and up and use the load bank in an area withvariable transformer should be treated to make sufficient ventilation and free from corrosivethem moisture and fungus resistant. Housing atmospheres or oily contaminants. Keep clearcan be sprayed with a varnish which offers of hazardous electrical connections or wires.protection against these hazards. Assure adequate working space for con-

C . Indoor In.stallation. The load bank venience and safety. Store in dry, clean areashould be set up in level position for best oper- and cover to keep dust off the load bank.

Section Il. MOVEMENT TO NEW WORKSITE

11. Dismantling for Movement (4) Disconnect leads to tested equipment

Disconnect the load bank from power plantterminal strip. Secure copper short-

before removing parts or assemblies. Procedureing links to cabinet by threaded stud

for dismantling the load bank in preparationand wing nut. Electrical leads and cir-

for moving to a new worksite is to:cuits should not be removed unlesstheir purpose is understood. Tag all

a. Disconnect the load as follows: leads and terminals to identify them

(1)

(2)

(3)

12

for reinstallation.Rotate the variable load control knob b. Inspection interior components for securi-(fig. 7) full counterclockwise. ty in mounting.Place all fixed load switches 3 c. Close and lock air exhaust door, controlthrough 7 in OFF position. panel door and other panels. Cover seams withStop tested equipment. pressure sensitive waterproof tape.

TM 5-6115-423-15

Figure 8. Controls and instruments-baffle assembly.

d. Remove mounting bolts or tie down rods,cables or lashing that fasten load bank to itsfoundation, skid or trailer.

e. Enclose the tester in an envelope of waterresistant barrier material and seal with water-proof pressure sensitive tape.

f. Encase the load bank and its envelope ofwater resistant barrier material in a strongwooden crate or box of adequate size. Whenshipped by truck, rail, or air the unit should

be blocked at the base and sides to preventshifting during transit. The load bank is de-signed to withstand an acceleration of 2.5 gfor a period of 0.10 seconds applied alongeach of the three major axis in both directions.

12. Reinstallation After Movement

Refer to paragraph 10 (InstallationSetting-Up Instructions) for procedure ininstalling the load bank after movement.

Section Ill. CONTROLS AND INSTRUMENTS

13. General ments for proper operation of

This section describes, locates, illustrates and 14. Controls and Instruments

orre-

the load bank.

furnishes the operator, crew or organizational The purpose of the controls and instrumentsmaintenance personnel with sufficient infor- and the normal and maximum reading of themation about the various controls and instru- instruments are illustrated in figure 7.

13

TM 5-6115423-15

Section IV. OPERATION OF EQUIPMENT

15. General

a. The instructions in this section are pub-lished for the information and guidance ofpersonnel responsible for operation of theload band.

b. The operator must know how to performevery operation of which this load bank iscapable. This section gives instructions forstarting and stopping, basic operations of theload bank and coordination of these functionsto perform the specific tasks for which theequipment is designed. Since nearly every jobpresents a different problem, the operator mayhave to vary a given procedure to fit the indi-vidual job.

16. Starting the Equipment

a. Preparation for starting.

(1)

(2)(3)

(4)

(5)

14

Perform the necessary daily preven-tive maintenance services.Check load requirements.Make sure that all ventilating doorsare open and unobstructed, thattoggle switches are in OFF position,and that variable load control knobis turned full counterclockwise.Open the exhaust door for access tothe connector plug, two receptaclesand terminal strip TB. Plug connec-tor and receptacles are located onthe baffle assembly. The plug wheninserted in the low voltage receptaclefor loading generators rated 120/208volts, 3-phase 4-wire; 120 volts singlephase two wire or 240 volts 3-phase,3-wire. High voltage receptacle JIBsets up input connections for load-ing generators rated 240/4 16 volts,3-phase 4-wire and 240 volts singlephase 2-wire. Depending uponwhether the relay senses high or lowvoltage, the Plug P, must be insertedinto the proper receptacle (either J1Aand J1B) for the loading circuitry tofunction.Connect leads to tested equipment toterminal strip for s ingle or three

phase load tests, Make the followingconnections.

(a)

(b)

(c)

(d)

Single Phase Connection. To loada single phase generator tie theterminals L1, L2, and L, togetherby means of two copper shortinglinks (fig. 8) which are furnishedwith the unit. Connect leads fromtested equipment securely to L,and L0 on terminal board. Handtighten knobs.Three Phase, Three Wire Connec-tion. To load a three phase, three-wire generator, connect leads toterminals L1, L2, and L,. Do notuse the copper shorting links to tiethe terminals together.Three Phase, Four Wire Connec-tions. To load a three phase, four-wire generator connect leads toterminals L1, L2, L3, and neutralline L0. Do not use the coppershorting links to tie the terminalstogether.Ground lead. Connect the groundlead (fig. 2) on the control panelto an adequate ground such as awater pipe so as to properly groundthe metal chassis and cabinet.

b. Starting. Refer to figure 9 and start theload bank.

Warning: High currents and voltages maybe present at the load bank resistive elementsduring check out test. Dangerous shock haz-ards are present, Do not place hands or toolsnear the motor fan while the Load Bank isenergized.

Warning: Very toxic fumes of selenium dio-xide are given off when selenium coated platesburn. Never breathe the fumes. Keep fumesor compound away from your skin. Handlethe burned plates with gloves; dispose ofgloves or contaminated materials as prescribedfor toxic materials.

17. Stopping the Equipment

a. Refer to figure 10 and stop the load bank.

TM 5-6115-423-15

Figure 9. Starting load bank.

the necessary daily preventive (b) Add kilowatt by turning the vari-b. Performmaintenance services ( para 31).

18. Operation Under Usual Conditions

a. Insert the plug connector into the properreceptacle as described in paragraph 16, Start-ing The Equipment.

b. Combine fixed loads in increments of 3KW up through 27 KW and variable loadsinfinite variations from 0 to 3 KW. It is possi-ble to apply any load to the generator undertest from 0 to 30 KW. Several examples of howfixed and variable loads can be combined toachieve types of loading are given here:

(1) Example 1. Apply a load of 20 kilo-watts,

(a) Close fixed load toggle to apply afixed load of 18 kilowatts. Selecteither a combination of two 9kilowatt switches or the 3, 6 or 9kilowatt switches.

able switch on and the variable con-trol knob to a 2 killowatt reading.

(2) Example 2. Apply a load of 2 1/2kilowatts. Turn the variable controlknob to a reading of 2 1/2 kilowatts.

(3) Example 9. Apply a load of 28 kilo-watts.

(a)

(b)

Close all fixed toggle switches (3,6, 9, and 9 KW) to apply a loadof 27 kilowatts.Turn the variable switch on andturn the variable control knob toa 1 KW reading. This adds 1 kilo-watt to the 27 kilowatts, giving atotal loading of 28 kilowatts.

Note. The loads described above as wellas other combinations can be applied toany generator capable of being tested bythe bad Bank.

15

TM 5-6115-423-15

Figure 10. Stopping load bank.

19. Operation in Extreme Cold [Below 0° F)

The load bank is designed to operate attemperatures above minus 25 degrees Fahren-heit, but not below this temperature. Wherethe load bank is subjected to sub-zero tempera-tures, adequate protection should be providedagainst the deteriorating effects of wind, snowand ice. When practical portable electric heatersmay be placed inside the load bank to raiseambient temperature to at least zero degreesFahrenheit. Remove heater before putting loadbank in operation.

20. Operation in Extreme Heat

The load bank is designed to operate attemperatures up to 125 degrees F., but pro-longed exposure to enviorments of excessively

16

high temperature and humidity requires specialtreatment, with particular attention to use ofdessicants to inhibit corrosive action due tohigh moisture content.

21. Operation in Dusty or Sandy Areas

Inspect the load bank every 50 operatinghours or every month. Clean out and removeaccumulated dust and sand. Wipe electricalcomponents with a dampened soft cloth. Cleanthe interior of the load bank with a lowpressure jet of dry air. Do not wipe insulationwith cleaning solvents that may damageinsulation. In dusty atmosphere a fine screencan be placed across the front and back of theload bank so that air drawn through the unitis freed of dust.

TM 5-6115-423-15

22. Operation under Rainy or HumidConditions

Adequate use of dessicants will insure reduction of corrosion due to high humidity con-ditions in the atmosphere. Under conditions ofexcessive humidity or moisture and hightemperature, fungus growth is a possibility.Treat components such as the selenium recti-fier, variable transformer and power absorberfan motors with a protective coating such asvarnish that is resistant to moisture and fungi.

23. Operation in Salt Water Areas

Operation near salt water presents no ad-ditional problems other than those describedin paragraph 22.

24. Operation in High AltitudesThe load bank is designed to operate satis-

factorily at altitudes form sea level to 8000feet. It is not advisable to operate it abovean altitude of 8000 feet because electricalcharacteristics of insulation and connectionschange.

17

TM 5-6115422-15

CHAPTER 3

OPERATOR AND ORGANIZATIONAL MAINTENANCEINSTRUCTIONS

Section 1. SPECIAL TOOLS AND EQUIPMENT

25. Special Tools and Equipment ized for the load bank are listed in the basic

No special tools or equipment are required issue items list, Appendix C of this manual.

by the operator or organizational maintenancepersonnel for the maintenance of the load bank. 27. Organizational Maintenance

Repair Parts26. Basic Issue Tools and Equipment Organizational maintenance repair parts are

Tools and repair parts issued with or author- listed and illustrated in TM 5-6115-423-25P.

Section Il. LUBRICATION

28. General Lubrication InformationNo lubrication of the components of the

load bank is required. Three power absorberfan motors are equipped with factory lubri-cated sealed for life bearings.

Section Ill. PREVENTIVE

30. GeneralTo insure that the load bank is ready for

operation at all times it must be inspectedsystematically so that defects may be discoveredand corrected before they result in seriousdamage or failure. The necessary preventivemaintenance services to be performed are listedand described in ‘paragraphs 31 and 32. Theitem numbers indicate the sequence of mini-mum inspection requirements. Defects dis-covered during operation of the unit shall benoted for future correction, to be made as soonas operation has ceased. Stop operation immed-iately if a deficiency is noticed during opera-

29. Detailed Lubrication Information

An occasional drop of lubricating oil shouldbe applied to the cabinet door hinges whenrequired.

MAINTENANCE SERVICES

tion which would damage the equipment ifoperation were continued. All deficienciesand shortcomings will be recorded togetherwith corrective action taken on DA Form 2404(Equipment Inspection and MaintenanceWorksheet ) at the earliest ‘possible oppor-tunity.

31. Daily Preventive Maintenance Service

This paragraph contains an illustrated tabu-lated listing of preventive maintenance servicewhich must be performed by the operator. Theitem numbers are figure 11 for the daily pre-ventive maintenance services.

19

TM 5-6115-423-15

Figure 11. Daily preventive maintenance services.

20

TM 5-6115-423-15

Figure 12. Quarterly preventive maintenace services.

21

TM 5-6115423-15

32. Quarterly Preventive Maintenance calendar months or 250 hours of operation,Services which ever occurs first.

a. This paragraph contains an illustrated b. The item numbers are listed consecutivelytabulated listing of preventive maintenance and indicate the sequence of minimum requireservices which must he performed by orga-nizational maintenance personnel at quarterly ments. Refer to figure 12 for the quarterlyintervals. A quarterly interval is equal to 3- preventive maintenance services.

Section IV. OPERATOR MAINTENANCE

33. General

The instructions in this section are publishedfor the information of the operator in main-taining the load bank.

34. Fuse Replacement

Fuses F1, F2, and F3 are located in holdersmounted on the control panel in the upperright hand corner (fig. 7). To replace a fuseunscrew it counterclockwise (direction ofarrow ). Replace with new fuse. Screw in newfuse clockwise until snug. Do not overtighten.

35. Identification Plate Replacement

There are 12 identification plates on theGPT-3D–1 load bank. To remove any plate,remove rivets holding the plate to the chasis.Use new rivets to fasten the replacement plateto the chassis in the same location.

36. Fan Service

Refer to figure 15 and adjust the fan. In-spect or adjust fan only when load bank isdisconnected from power source. To removefan from fan motor shaft, loosen set screw onfan hub. Slip fan off shaft by placing fingersbehind blades and pulling gently toward endof shaft. Check for damage or distortion. Toreplace fan, slip hub of fan 3/8 inch from endof shaft. Retighten set screw firmly. To checkfor unbalance in blade, snap master switch to“on”,

Warning: Fan revolves at high speed, sokeep hands and tools free of path of rotatingblades

37. Doors and Panels

a. Removal and Installation. Refer to figure13 to remove and install the door, panel, andcover.

22

b. Cleaning and Inspection. Clean all partswith an approved cleaning solvent and drythoroughly. Inspect for cracks, breaks, or otherdamage. Replace all defective parts.

38. Wind Switch and Toggle Switchesa. Wind Switch. There is one wind switch

(fig. 15) located in each power absorber as-sembly. Inspect each switch for loose connec-tions, damage, and mechanical operation. Testswitch for continuity.

b. Toggle Switches. Inspect six toggleswitches located on the control panel for looseconnections, damage, tightness of mountingand mechanical operation. Test each switch forcontinuity.

39. RectifierInspect rectifier (fig. 3) for evidence of

burning on plates, loose connections, and se-cure mounting. Report burned plates to appro-priate maintenance facility for repair.

40. Terminal Studsa. Removal. The four terminal studs are lo-

cated on input terminal board TBI and areremoved as follows:

(1) Disconnect and tag wires from backof terminal board (see wiring dia-gram).

(2) Refer to figure 14 and remove theterminal studs.

b. Cleaning and Inspection. Clean all partswith an approved cleaning solvent and drythoroughly. Inspect for cracks, breaks, anddamaged or stripped threads. Replace all de-fective parts.

c. Installation. Refer to figure 14 and thewiring diagram and install the terminal studs.

TM 5-6115-423-15

Figure 13. Doors and panels.

23

TM 5-6115-423-15

MEC 6115-423-15/14

Figure 14. Terminal studs.

41. Filter Capacitors

Inspect the filter capacitors (fig. 3) visuallyfor damage and loose connections. Test for

shorts and proper capacitance if a capacitortester is available. Use an ohmmeter to testfor shorts Wing RX 10,000 scale. Make surethe capacitor is discharged prior to testing.Place one lead on body of capacitor and otherlead on terminal. If there are no shorts, theohmmeter will read infinity ( ∞ ). Then placeleads on capacitor in reverse of above withouttouching the capacitor with your fingers andthe needle should jump momentarily and thensettle back to ∞ resistance. Replace defectivecapacitor by disconnecting leads and removingmounting screw.

42. Connectors

Inspect connectors located on baffle assemblyvisually for damaged threads, broken connec-tions, and broken or damaged pins. Test forcontinuity. Replace defective connector by dis-connecting and tagging electrical leads andremoving four mounting screws and nuts.

Section V. TROUBLESHOOTING

43. General

44. Load Bank Fails to Start

45. Fixed Load Switches are on but no toadis Applied

Broken lead _______________ Replace faulty wire.

Loose connection ---------- Tighten connection.

Plug P1 is in wrong (para 44)receptacle.

46. Power Absorber Overheats

Insufficient ventilation---- Clear blocked air openings,clear away obstructions.

47. Radio Interference

Loose or broken suppres- Tighten or replace brush.sor brush on motor.

Load Band not grounded--- Be sure the chassis andcabinet are grounded.

Defective capacitors C, Replace capacitors.and C2.

24

T M 5 + 1 1 5 4 2 > 1 5

480 Variable Load Switch Does Not Apply 49. Load Drops SuddenlyProbable cause Possible remedy

Probable cause Possible remedy Fuses F1, F2, and F3, Replace blown fuses.blown Reapply load.

Variable Load Control Position load switch to ON. Generator failure--------------- Check and replace withswitch not in ON position new generator.

Loose or broken leads---- Tighten or replace leads. Selenium rectifier burn- De+energize load bank,ing or has failed (ac- remove outside to

Plug P1 in wrong (pana 44) companied by acrid dissipate fumes. Replacereceptacle. stench) . damaged rectifier.

Section VI. RADIO INTERFERENCE SUPPRESSION

50. Definitions

a. Interference. The term “interference” asused herein applies to electrical disturbancesin the radio frequency range which are gener-ated by the load bank and which may inter-fere with the proper operation of radio re-ceivers or other electronic equipment, or enablean enemy to locate the equipment.

b. Interference Suppression. The term“interference suppression” as used herein ap-plies to the methods used to eliminate oreffectively reduce radio interference generatedby the load bank.

51. General Methods Used to Attain ProperSuppression

Essentially, suppression is attained by pro-viding a low resistance path to ground stray

currents. The methods used include shieldingthe ignition and high-frequency wires, ground-ing the frame with bonding straps, and usingcapacitors and resistors.

52. Radio Interference SuppressionComponents

Suppression is attained through a radiosuppression brush grounded to the frame ofthe motor housing and which rides on themotor housing and which rides on the rotatingshaft and through capacitors C1 and C,. Spark-ing and other electrical disturbances arequickly grounded and suppressed.

53. Replacement of SuppressionComponents

Refer to figure 15 and replace the radiointerference suppression components.

2 5

T M 5 4 1 1 5 4 2 2 - 1 5

Figure 15. Radio interference suppression.2 6

TM 5-6115-423-15

CHAPTER 4

DEMOLITION OF EQUIPMENT

Section 1. DEMOLITION OF LOAD BANK TO PREVENT ENEMY USE

54. General

a. When capture or abandonment of the loadbank to an enemy is imminent, the responsi-ble unit commander must make the decisioneither to destroy the equipment or render itinoperative. Based on this decision, orders areissued which cover the desired extent of de-struction. Whatever method of demolition isemployed, it is essential to destroy the samevital parts of all load banks and all corre-sponding spare parts.

b. When lack of time or personnel preventscomplete destruction of the equipment, thefollowing priorities will be used in the destruc-tion of essential parts

(1)

(2)

(3)

(4)

(5)

Control panel assemblyPower absorbersVariable transformerContactorRectifier

55. Demolition to Render the EquipmentInoperative

a. Mechanical Means. Use sledge hammers,crowbars, picks, axes or any other heavy toolswhich may be available to completely destroythe following:

(1) Control panel

(2) Power absorbers

(3) Variable transformer

Note. The above steps are minimum re-quirements for this method of destruction.

56. Demolition by Explosive orWeapons Fire

a. Explosives. Place charges in interior o funit and detonate them simultaneously with asuitable detonator and detonating cord.

b. Weapons Fire. Fire on the load bankwith the heaviest practical weapons available.

57. Other Demolition Methods

a. Scattering and Concealment. Remove alleasily accessible parts and scatter them throughdense foliage, bury them in a lake, stream, orother body of water.

b. Burning, Pack rags, clothing, or canvasinside, under and around the load bank. Satu-rate this packing with gasoline, oil or dieselfuel and ignite it.

c. Submersion. Totally submerge the equip-ment in water to provide water damage andconcealment. Salt water does greater damageto metal parts than fresh watar.

58. Training

All operators should receive training in thedestruction of the load bank. Refer to FM5-25. Simulated destruction using all of themethods listed, should be included in the train-ing program. It must be emphasized in train-ing that demolition operations are usuallynecessitated by critical situations when timeavailable for carrying out destruction is limitedFor this reason, it is necessary that operatorsbe thoroughly familiar with all methods ofdestruction of equipment, and be able to carryout demolition instructions without referenceto this or any other manual.

27

TM 5-6115-423-15

CHAPTER 5

DIRECT SUPPORT, GENERAL SUPPORT ANDDEPOT MAINTENANCE INSTRUCTIONS

Section I

59. ScopeThese instructions are published for the use

of field and depot maintenance personnel main-taining the Sun Electric Model GPT-3D–1load bank. They provide information on themaintenance of the equipment which is beyondthe scope of the tools, equipment, personnelor supplies normally available to using orga-nizations.

GENERAL

60. Record and Report Forms

For record and report forms applicable todirect and general support and depot mainte-nance, refer to TM 38-750.

Note. Applicable forma, excluded standard Form 46(United States Government Vehicles Operator’s Identi-fication Card) which is carried by the operator shallbe, kept in a canvas bag mounted on the equipment.

Section Il. DESCRIPTION AND DATA

61. Description

For a complete description of the load bankModel GPT-3D-1 see paragraph 8.

62. Tabulated Data

a. General. This paragraph contains all theoverhaul data pertinent to the direct andgeneral . support and depot maintenancepersonnel. A wiring schematic (fig. 16) is alsoincluded.

b. Electrical Power Absorber, Classificationand Rating.

Rating ------------------- 10 kwResistive element ---------- 1/8-inch Nichrome wire,

wound counterclockwise,number of turns, spacingand length of ribbon isdetermined by wiringassembly. Motor leads,thermal overload(kilixon) and air switchleads brought outthrough clamp to ter-minal board.

Mounting----------------- Mount fan hub 3/8-inchfrom end of shaft.

Figure 16. Load bank wiring schematic.(Located in back of manual)

c. Fan Motor.Type_____________________28 volts DC from AC

input power throughtransformer-rectifiermodule.

Ratting ------------------- 1/20 HP minimum at3600 RPM

Duty__________________ContinuousDegree enclosure____________FullMounting______________Motor mounting bracket

within power absorberRpm_______________ 3600 rpm minimum

4000 rpm maximum

d. Auto-transformer, Classifact ion andRating.Rating____________ 240 volt, 50-1000 cps,

single phase input, 120volts ±1% output at1 km Forced air coolingat 600 Lineal feet/minute

125° F ambient

29

TM 5-6115-423-15

Mounting dimensions ______ width: 4 inchesheight: 4 5/8 inches plus1 1/8 inches (terminal)length: 5 1/4 inches5/6 x 9/16 incheselongated mountingholes in base

e. Control transformer, Classification andRating.Rating_.. ---------------- 120/240 volt, 50-1000 cps

single phase dual voltageinput, output:

Rating ______ ____________ 34.5 ±0.4 at open circuit31.5 ±0.4 volts at 2.0amperes26.0 * 0.4 volts at 6.0amperes

Capacity _________________ 115 VA, forced air cooledat 500 lineal feet perminute. At 125” F.ambient must be capableof operating at 138/276volts input

Mounting dimensions ------ Width: 3 5/8 inchesheight: 4 3/16 inchesplus 5/8 inches (ter-minals)Length: 4 1/2 inches.

f. Selenium Rectifier, Classification andRating.Rating-_________________ 2.5 amperes, 30 VOltS DC

at 122” F ambient con-vection cooled composedof four 3.3 inch, 40 voltRMS cells connected in

single phase, full wavebridge

g. Contactor, Classification and Rating.Rating ------------------- 3 PST 200 amperes, 200

volts 400 cycle 28 voltDCControls 40 kw 3-phaaewye connected bal.resistive load120/208 v. 3-phase,4-wire 240 v. 3 phase,3 wire 240/416 v. 3-phase 4-wire input at50-1000 cycles/see.

h. Relay, Classification and Rating.Type rating -------------- 150 volts minimum

200 volts maximum50-1000 cps

i. Variable Transformer, Classification andRating.Rating -------------------- 0-3 KW 3-gang 3-phase

10 amperes maximumoutput

Rating _________________Stepless, manually adjusted,output 0-240 volts240 volt input constantimpedance load, 319°rotation

Dimensions --------------- Length: 16 7/8 inchesHeight: 5 5/8 inchesWidth: 6 inches

j. Practical Wiring Diagrarn. Figure 5 showsthe practical wiring diagram for this load bank.

30

TM 5-6115-423-15

CHAPTER 6

GENERAL MAINTENANCE INSTRUCTIONS

Section 1. SPECIAL TOOLS AND EQUIPMENT

63. Special Tools and Equipment 64. Specially Designed Tools and Equipment

No special equipment or tools are required No specially designed equipment or toolsby direct and general support and depot main- are required by direct and general and depottenance personnel for performing maintenance maintenance personnel for performing mainte-on the load bank. nance on the load bank.

Section Il. TROUBLESHOOTING

65. General

This section provides information useful indiagnosing and correcting unsatisfactory oper-ation or failure of the load bank or any of itscomponents. Each trouble symptom statedfollowed by a list of probable causestrouble. The possible remedy recommendeddescribed opposite the probable cause.

66. Fixed Load Switches are on but noLoad is AppliedProbable cause Possible remedy

Defective contactor K-1 .-Replace or repair con-tactor (para 76, 88).

isofis

Defective increment or air Replace sitches (fig. 15).flow switches.

Defective relay K-2------- Replace or repair relay(para 75, 86).

Thermal switches _________ (para 3c(3) )Transformers ------------- (para 79, 82 and 92)Rectifiers----------______.(para 39)Fixed and variable load (para 86b)

switches.Wind switches ------------ (para 38a)

67. Power Absorber OverheatsProbable cause Possible remedy

Fan inoperative ____________ Repair or replace fanmotor if faulty. Tightenfan blade if loose. Checkand retighten connec-tions to fan motor(para 36 and 90).

68. Relay Does Not OperateProbable cause Possible remedy

Relay is defective_________Test and replace relay ifdefective (para 75)

69. Variable Load Switches Does NotApply LoadProbable cause Possible remedy

Variac brushes worn________Check and replace variabletransformer if brushesare worn (para 72 and79) .

70. Load Drops SuddenlyProbable cause Possible cause

Contactor (K1) operating Replace contactor (K1)improperly. (para 76).

Section Ill. REMOVAL AND INSTALLATION OF MAJOR COMPONENTS

71. General formers, auto transformers, rectifier, relay,This section contains instructions for the re- contactor, power absorbers, and control trans-

moval and installation of the variable trans- formers. Refer to figure 13 to remove any

31

TM 5-6115-423-15

panel or door allowing access to the majorcomponent.

72. Variable Transformera. On

(1)(2)

(3)

(4)

(5)

(6)

Equipment Test.Refer to figure 6 and 9.De-energize load bank and connectvoltmeter to terminals # 1 and #4.Energize load bank. Reading shouldbe of 240 volts AC.De-energize load bank and connectvoltmeter to terminals #3 and #4.Energize load bank and turn the var-iable control all the way counterclock-wise. The voltmeter should read 0.volts. Turn the variable control gradu-ally clockwise until it is all the wayclockwise. The voltmeter readingshould gradually increase to 240 voltsAC.If these readings are not obtained, re-

b. Removal and Installation.17 to remove and install theformer.

73. Auto Transformers

a. On Equipment Test.

Refer to figurevariable trans-

(1)(2)

(3)

(4)(5)

(6)

(7)

Refer to figure 5 and 18.De-energize load bank and connectvoltmeter to terminals H1 and X2.Energize load bank with 240/416volts AC.Voltmeter should read 240 volts.De-energize load bank and connectvoltmeter to X1—X2.Re-energize load bank and voltmetershould read 120 volts AC.If this reading is not obtained, re-place auto transformer.

b. Removal and Installation. Refer tofigure 18 to remove and install the auto trans-

32,figure 17. Variable transformer removal and indstallation.

74. Rectifiera. On Equipment Test. Refer to paragraph

84d.b. Removal and Installation. Refer to figure

19 to remove and install rectifier.

75. Relaya. On Equipment Test, Refer to paragraph

82d.

b. Removal and In.stallation. Refer20 to remove and install the relay.

76. Contactor

to figure

a. On Equipment Test. Refer to paragraph84d.

b. Removal and Installation. Refer to figure21 to remove and install the contractor.

TM 5-6115422-15

77. Power Absorbersa. On Equipment Test.

(1) De-energize load bank,(2) Remove all wires and tags.(3) Check each coil for continuity.(4) Check for grounds.(5) Replace wires.

b. Removal and Installation. Refer to figure22 to remove and install the power absorbers.

78. Control Transformers

a. On(1)

(2)

(3)

Equipment Test.De-energize load bank, and connectvoltmeter to terminals H1 and H2.Energize the load bank and the volt-meter should read 120 VAC.Repeat by connecting to terminals H3and H4. The same reading should beobtained.

Figure 18. Auto transformer removal and installation.

33

TM 5-6115-423-15

(4) De-energize the load bank and con- (6) If these readings are not obtained,nect voltmeter to terminals Xl and replace the control transformer.X2.

(5) Energize load bank and the voltmeter b. Removal and Installation. Refer to figure

should read between 24 and 30 volts 23 to remove and install the step down trans-AC. formers.

Figure 19. Rectifier removal and installation

34

TM 5-6115-423-15

Figure 20. Relay removal and installation.

35

TM 5-6115-423-15

Figure 21. Contactor removal and installion.

36

TM5-6115-423-15

Figure 22. Power absorber removal and installation.

37

TM 5-6115-423-15

F i g u r e 2 3 . R e l a y r e m o v a l a n d i n s t a l l a t i o n .

38

TM 5-6115-423-15

CHAPTER 7

REPAIR INSTRUCTIONS

Section 1. REPAIR OF VARIABLE TRANSFORMER

79. General c. Cleaning, Clean all metal parts with an

The variable transformer is a three gang, approved cleaning solvent and dry thoroughly.

240 volt, 50 to 1000 cps input, 0 to 240 volt, d. Inspecting. Visually inspect the variable10 ampere maximum output, three phase wye transformer for cracks, damaged threads, and

constant impedance load unit. It provides bent terminals. Inspect variac brushes for wear,

stepless control of load from 0 to 3 kw. It is corrosion, or damage.operated manually by a control knob located on e. Testing.the

80.

72.b.

control panel.(1)

Repair of Variable TransformerOn Equipment Test. Refer to paragraph

(2)Removal and Installation. Refer to para-

graph 72 to remove and install the variabletransformer.

Test each gang transformer for opencircuits using a multimeter applied toeach of two terminals in combination.Test each gang transformer forgrounds or insulation breakdown byapplying one probe of multimeter toeach terminal and the other to ground.

Section Il. REPAIR OF AUTO TRANSFORMER

81. General c. Cleaning. Clean dust and dirt from auto

The auto transformer is rated as follows:transformer using compressed air.

d. Inspecting. Visually inspect the auto240 volt, 50 to 1000 cps, single phase input;120 volt ±1 percent output at 1 KW; forced

transformer for bent terminals, damaged orstripped threads, loose connections, and frayed

air cooling at 500 lineal feet per minute, 125 insulation.degree F. ambient. e. Testing.

(1) Test the auto transformer for open82. Repair of Auto Transformer circuits using a multimeter applied to

a. On Equipment Test. Refer to paragrapheach of two terminals in combination.

73.(2) Test the auto transformer for grounds

or insulation breakdown by applyingb. Removal and Installation.

graph 73 to remove and installformer.

83. General

Refer to para- one probethe auto trans- terminal in

to ground.

Section Ill. REPAIR OF RECTIFIER

connected in single

to multimeter to eachturn, and the other probe

phase,The rectifier is of the selenium type, consist- rated at 30 volt DC at 122

ing of four 3 by 3 inch, 40 volt rms cells and is convection cooled.

full wave bridge,degrees F ambient,

39

TM 5-6115-423-15

84. Repair of Rectifier d. Testing. Apply probes of’ multimetera. Removal and Installation. Refer to para- across the cells of rectifier and observe reading.

gaph 74 to remove and install the rectifier. Reverse the multimeter probes and observeb. Cleaning. Clean dust and dirt from recti-

fier using compressed air.reading. The difference between the two read-

C. Inspecting. Visually inspect the rectifier ings is the front-to-back ratio and should be

for bent terminals. stripped or damaged about 500 to 1 or greater. Replace rectifierthreads, and bent or’ damaged plates. - with high front-to-back ratio.

Section IV. REPAIR OF RELAY

85. General b. Cleaning. Clean case of relay with an

The relay is rated as follows: 3 pole double approved cleaning solvent and dry thoroughly.throw, 3 ampere inductive at 120 volts AC and1 ampere inductive at 240 volts AC, 50 to1000 CPS, continuous duty, 240 volt coil nomi-nal. Pull-in between 150 and 200 volts maxi-mum with maximum differential between startof pull-in and sealed condition of 12 volts atany frequency between 50 and 1000 cps.

86. Repair of Relay

a. Removal and Installation. Refer to para-graph 75 to remove and install the relay.

c. In.specting. Visually inspect the relay forstripped or damaged threads, and for damageto the case.

d. Testing. Monitor each contact using 115volt AC lamp in series with each contact (6lamps). No dimming of the lamps shouldoccur between 0 to 150 volts 50 to 1000 cyclesinput. Lamps should be at full brightness at

an input of 200 volts, 50 to 1000 cycles.

Section V. REPAIR OF CONTACTOR

87. General 88. Repair of Contactor

The contactor is rated at 200 ampere, 200 a. Removal and Installation. Refer to para-volt, 400 cycle, 3-pole single throw, 28 volt graph 76 to remove and install the contactor.

DC operated. It is capable of controlling a 40 b. Cleaning. Clean case of contactor with

kw, 3 phase wye connected balanced resistive an approved solvent and dry thoroughly.

load at 120/208 volt, 3-phase, 4-wire; 240 volt, c. Inspecting. Visually inspect contactor fordamage to case.

3-phase, 3-wire; or 240/416 volt, 3-phase, 4- d. Testing. Apply a voltage to coils of con-wire input at any frequency between 50 to 1000 tractor and check that they operate. Check forcycles. burned or pitted contacts

Section VI. REPAIR OF POWER ABSORBERS

89. General protected by a wind switch and a thermal over-load switch set at 120 degrees C.

The three duck-type, 10 kw power absorbersprovide the load bank with the necessary resis- 90. Repair of Power Absorbers

tive loads.. The resistive elements are 1/8 inch a. Removal and Installation. Refer to para-corrugated nichrome ribbon enclosed within a graph 77 to remove and install the power ab-slotted housing. The unit is fan cooled, and sorbers.

40

b. Disassembly. Disassemble the powerabsorbers in the numerical sequence shown orfigure 24.

c. Cleaning. Clean all non-electrical partswith an approved cleaning solvent and drythoroughly. Clean all electrical parts with a drylint-free cloth.

d. Inspecting. Visually inspect all parts forcracks, damage and stripped or damagedthreads. Check wind switch for continuity. Usea Strobotac and check the rpm of the fan motorshaft. Allowable tolerance is 3300 to 4000 rpm.

e. Reassembly. Reassemble the power ab-sorber in the reverse of the numerical sequence

T M 5 - 6 1 1 5 - 4 2 3 - 1 5

as illustrated on figure 24. Observe the follow-ing:

(1)

(2)

(3)

Start winding the resistive element atthe fan end of absorber at post No.1, in second groove. Wind in acounterclockwise direction.Mount fan with hub 3/8 inch fromend of shaft.Feed motor leads, thermal overloadswitch leads, and wind switch leadsthrough clamp (50) and behind busbar (39). After connecting leads toterminal board (45) dress them awayfrom bus bar.

Section VII. REPAIR OF CONTROL TRANSFORMERS

91, General

The control transformers are rated asfollows: 120/240 volt, 50 to 1000 cps, singlephase, dual volt input; 34.5 ±0.4 volt at opencircuit, 31.5 ±0.4 volts at 2.0 ampere, 26.0±0.4 volts at 5.0 ampere output. The trans-former is forced air cooled at 500 lineal feetper minute at 125 degrees F.

92. Repair of Control Transformer

a. On Equipment Test. Refer to paragraph78.

b. Removal and Installation. Refer to para-graph 78 to remove and install the controltransformer.

c. Cleaning. Clean thewith compressed air and

d. Inspecting. Visually

control transformera dry lint-free cloth.

inspect the controltransformer for bent terminals, stripped ordamaged threads, and frayed or damagedinsulation.

e. Testing.(1)

(2)

Test the control transformed for opencircuits using a multimeter applied toeach of two terminals in combination.Test the control transformer forgrounds or insulation breakdown byapplying one probe of multimeter toeach terminal in turn, and the otherprobe to ground.

41

TM 5-6115-423-15

MEC 6115-423-15/24

Figure 24. Diasassembly of electrical power absorbers.

42

Figure 4

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Machine screw, 10-32x 3/8 (2)Nut, 10-32 (2)supportMachine screw, 10-32 x 3/8 (2)Nut, 10-32 (2)Bracket (2)FanMachine screw, 6-32 x 1/2 (3)Flat washer, No. 6 (3)Nonmetallic washer (3)Nonmetallic washer (6)Nut, 10-32 (6)Flat washer, No. 10 (4)Radio suppression brushBracketFlat washer, No. 10 (4)Fan motorMachine screw, 8-32 x 1/4 (12)supportMachine screw, 8-32 x 3/6 (18)Nut, 8-32 (18)Resistive element (9)Bus bar (2)Lug temninal (14)Thread cutting screw, 6 x 8/8 (2)Lock washer No. 6 (2)DuctMachine screw, 8-32 x 1/4 (12)Spring (12)Insulator (96)Post (12)

32333435363738394041424344464647484950515253645556575659606162

Spacer (9)spacer (4)Spacer (9)Nut 1/4-20 (3)Lock washer 1/4 (2)Flat washer 1/4 (4)Shoulder bushingBus barTerminal studShoulder bushingMachine screw, 8-32 x 5/8 (4)Flat washer, No. 8 (4)Nut, 8-32 (4)Terminal boardMarker stripLug terminalThread cutting screw, 6 x 3/8 (2)Lock washer, No. 6 (2)Loop clampWind switchThread cutting screw, 6 X 3/8 (2)Lock washer, No. 6 (2)Cooling tube assycoverPlatescrew (2)Washer (2)PlateScrew (4)washer (4)Breaker Assembly

43

TM 5-6115-423-15

Figure 25.

TM 5-6115-423-15

Figure 26

45

TM 5-6115-423-15

Figure 27.

46

TM 5-6115423-15

F i g u r e 2 8 .

47

TM 5-6115-423-15

Figure 29.

4 8

TM 5-6115423-15

APPENDIX A

REFERENCES

TM 38-750 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - The Army Equipment Record System and Pro-cedures.

TM 5-6115-423-25P ------------------ --- Organizational, Direct and General Support andDepot Maintenance Repair Parts and SpecialTools Manual.

49

TM 5-6115-423-15

APPENDIX B

MAINTENANCE ALLOCATION CHART

Section 1. INTRODUCTION

1. Generala. This section provides a general explana-

tion of all maintenance and repair functionsauthorized at various maintenance levels.

b. Section II designates overall responsibil-ity for the performance of maintenance oper-ations on the identified end item or component.The implementation of the maintenance tasksupon the end item or component will be con-sistent with the assigned maintenance oper-ations.

c. Section III lists the special tools and testequipment required for each maintenance oper-ation as referenced from section II.

2. Explanation of Columns in Section II

a. Functional Group Number. The function-al group is a numerical group set up on afunctional basis. The applicable functionalgrouping indexes (obtained from TB 750-93-1, Functional Grouping Codes) are listed onthe Maintenance Assignment in the ap-propriate numerical sequence. These indexesare normally set up in accordance with theirfunction and proximity to each other.

b. Component Assembly Nomenclature.This column contains a brief description of thecomponents of each functional group.

c. Maintenance Functions and MaintenenceCategories. This column lists the various main-tenance functions (A through K) and indicatesthe lowest maintenance category authorized toperform these operations. The symbol designa-tions for the various maintenance categories areas follows:

C — Operator or crewO — Organizational maintenance

F — Direct support maintenaceH — General support maintenanceD — Depot maintenance

The maintenance functions are defined asfollows:

A—Inspect: Verify serviceability and detectincipient electrical or mechanical fail-ure by close visual examination.

B-Test: Verif y serveability and detectincipient electrical or mechanical fail-ure by measuring the mechanical or elec-trical characteristics of the item and com-paring those characteristics with author-ized standards. Tests will be made com-mensurate with test procedures andwith calibrated tools and/or test equip-ment referenced in the maintenanceassignment.

C-Service: Operations required periodical-ly to keep the item in proper operatingcondition, i.e., to clean, preserve, drain,paint, and replinish fuel, lubricant, hy-draulic, and deicing fluids, or com-pressed air supplies.

D—Adjust: Regulate periodically to pre-vent malfunction. Adjustments will bemade commensurate with adjustmentprocedures and associated equipmentadjustment specifications.

E-Align: Adjust two or more compo-nents of an electrical of mechanicalsystem so that their functions are prop-erly synchronized or adjusted.

F—Calibrate: Determine, check, or rectifythe graduation of an instrumentweapon, or weapons system or compo-nents of a weapons system.

51

TM 5-6115423-15

G—Install: Remove and install the sameitem for service or when required forthe performance of other maintenanceoperations.

H—Replace: Substitute serviceable compo-nents, assemblies and subassemblies forunserviceable counterparts.

I—Repair: Restore to a serviceable condi-tion by replacing unserviceable parts orby any other action required usingavailable tools, equipment and skills, in-cluding welding, grinding, riveting,straightening, adjusting and facing.

J—Overhaul: Restore an item to a complete-ly serviceable condition (as prescribedby serviceability standards developedand published by the commodity com-mands) by employing techniques of “In-spect and Repair Only As Necessary”( I ROAN). Maximum use of diagnosticand test equipments combined with mini-mum disassembly during overhaul.“Overhaul” may be assigned to any levelof maintenance except organizational,provided the time, tools, equipment, re-pair parts authorization, and technicalskills are available at that level. Nor-mally, overhaul as applied to end items,is 1 limited to depot maintenance level.

K—Rebuild: Restore to a condition com-parable to new by disassembling to determine the condition of each compo-nent part and reassembling using serv-iceable, rebuilt, or new assemblies sub-assemblies, and parts.

d. Reference Note. This column, subdividedinto columns L and M, is provided for refer-encing the Special Tool and Test EquipmentRequirements (sec. HI) that may be associ-ated with maintenance functions ( Section II).

3. Explanation of Columns in Section III

a. Referenre Code. This column consists ofa number and a letter separated by a dash.The number references the T&TE requirementscolumn on the Maintenance assignment. Theletter represents the specific maintenancefunction the item is to be used with. The letteris representative of columns A through K onthe Maintenance assignment.

b. Maintenance Category. This columnshows the lowest level of maintenance author-ized to use the special tool or test equipement.

c. Nomenclature, This column lists thename or identification of the tool or test equip-ment.

d. Tool Number. This column lists themanufacturer’s code and part number, orFederal stock number of tools and test equip-ment.

52

TM 5-6115-423-15

53

T M 5 - 6 1 1 5 - 4 2 3 - 1 5

APPENDIX C

BASIC ISSUE ITEMS

Section 1. INTRODUCTION

1. ScopeThis appendix lists items which accompany

the load bank or are required for installation,operation, or operator’s maintenance.

2. General

Basic Issue Items-Section II. This sectionis a listing of accessories, repair parts, tools,and publications required for operator’s main-tenance and operation, initially issued with, orauthorized for the load bank.

3. Explanation of Columns

The following provides an explanation ofcolumns in the tabular list of basic issue items,Section II:

a. Source, Maintenence, and RecoverabilityCodes (SMR), Column 1:

(1) Source Code indicates the selection

P

M

A

status and source for the listed item.Source codes are:

Applied to repair parts which are stockedin or supplied from GSA/DSA Armysupply system, and authorized for useat indicated maintenance categories.

Applied to repair parts which are not pro-cured or stocked but are to be manu-factured at indicated maintenance cate-gories.

Applied to assemblies which are not pro-cured or stocked as such, but made upof two or more units, each of whichcarry individual stock numbers anddescriptions and are procured andstroked and can be assembled by unitsat indicated maintenance categories.

X

Xl

X2

C

G

Applied to parts and assemblies which arenot procured or stocked, the mortalityof which is normally below that of theapplicable end item, and the failure ofwhich should result in retirement ofthe end item from the supply system.

Applied to repair parts which are not pro-cured or stocked, the requirement forwhich will be supplied by use of thenext higher assembly or components,

Applied to repair parts which are notstocked. The indicated maintenancecategory requiring such repair partswill attempt to obtain them throughcannibalization; if not obtainablethrough cannibalization, such repairparts will be requisitioned with sup-ing justification through normal supplychannels.

Applied to repair parts authorized for lo-cal- procurements. If not obtainablefrom local procurement, such repairparts will be requisitioned through nor-mal supply channels with a supportingstatement of nonavailability from localprocurement.

Applied to major assemblies that are pro-cred with PEMA (ProcurmentEquipment Missile Army) funds forinitial issue only to be used as exchangeassemblies at DSU and GSU level orreturned to depot supply level.

Note. Source code is not shown on common hard-ware items known to be readily available in Army sup-ply channels and through local procurement.

(2) Maintenance code indicates the lowestcategory of maintenance authorized toinstall the listed item. The mainte-nance level code is:

55

TM 5-6115-423-15

(3) Recoverability Code indicates whetherunserviceable items should be re-turned for recovery or salvage. Itemsnot coded are expendable. Recover-ability codes are:

R Applied to repair parts and assemblieswhich are economically reparable atDSU and GSU activities and are nor-mally furnished by supply on an ex-change basis.

T Applied to high dollar value recoverablerepair parts which are subject to spe-cial handling and are issued on an ex-change basis. Such repair parts arenormally repaired or overhauled at de-pot maintenance activities.

u Applied to repair parts specifically se-lected for salvage by reclamation unitsbecause of precious metal content, criti-cal materials, high dollar value reusablecasings and castings.

b. Federal Stock Number, Column 2. Thiscolumn indicates the Federal stock number forthe item.

c. Description, Column 3. This column indi-cates the Federal item name and any additionaldescription required. A five-digit manufactur-er’s or other service code is shown in parenthe-ses followed by the manufacturer’s partnumber. Repair parts quantities included inkits, sets, and assemblies that differ from the

actual quantity used in the specific item, arelisted in parentheses following the repair partname.

d. Unit of Issue, Column 4. This columnindicates the unit used as a basis of issue, e.g.,ea, pr, ft, yd, etc.

umn 5. This column indicates the actual quanti-ty contained in the unit pack.

f. Quantity Incorporated in Unit, Column 6.This column indicates the quantity of the itemused in the equipment.

g. Quantity Furnished With Equipment,Column 7. This column indicates the quantityof an item furnished with the equipment inexcess of the quantity incorporated in the unit.

h. Quantity Authorized, Column 8. Thiscolumn indicates the quantity of an item author-ized the operator/crew to have on hand or toobtain as required. As required items are indi-cated with an asterisk.

i. Illustration, Column 9. This column isdivided as f ollows:

(1) Figure Number, column 9a, indicatesthe figure number of the illustrationin which the item is shown.

(2) Item Number, column 9b, indicatesthe callout number used to referencethe item in the illustration.

56

Section II

TM5-6115-423-15

57

TM 5-6115-423-15

INDEX

26

41427688147892

816032951137

864145284

2851

4858910

44492928

2119202423221827

8777

7382

8289

19

24243340133341

1925

199

1222

222424

322

1925

822111111

24251919

1616161717171519

2288

3

59

TM 5-6115-423-15

Power absorber overheats - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Power absorbers, repair of - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Preventive maintenance service, daily --------------------------------------------Preventive maintenance services, quarterly --------------------------------------

Quarterly preventive maintenance services --------------------------------------

Radio inter ference - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Radio interference suppression components --------------------------------------Record and report forms --- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Reinstallation after movement --------------------------------------------------R e c t i f i e r - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Relay ________________________________________________________________________Repair of Autotransformer _____________________________________________________Repair of contactor ____________________________________________________________Repair of control transformer __________________________________________________Repair of power absorbers ______________________________________________________Repair of rectifier - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Repair of relay ________________________________________________________________Repair of variable transformer _________________________________________________Replacement of suppression components __________________________________________

Scope - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Special tools and equipment ____________________________________________________Specially designed tools and equipment __________________________________________Starting the equipment ________________________________________________________Stopping the equipment _______________________________________________________

Tabulated data - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - - - - -Tabulated data identification and ___-_-_-----__-____________________________—---Terminal s tuds - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Toggle switches, wind switch and ______________________________________________Transformers, auto ____________________________________________________________Trans formers , contro l - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Trans formers , var iab le - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Unloading the equipment _______________________________________________________Unpacking the equipment _____________________________________________________

Variable load switch does not apply load ----------------------------------------Var iab le t rans former - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -Variable transformer, repair of _---_----_-__----------------:-------------------

Wind switch and toggle switches ____---------------------__-_--_---—------—--

46903132

32

475221239758288929084868053

125641617

6244038737872

67

487280

38

24401922

22

2425

31322333940414040403925

318311414

298

2222323333

1111

253239

22

60

TM 5-6115-423-15

61

PIN : 025635-000

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