CAT BUCYRUS MARION 301-M MINING SHOVEL ELECTRICAL SERVICE MANUAL BI005615 - PDF DOWNLOAD

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MINING SHOVEL, /.,... , ELECTRICALSERVICE MANUAL c 1<

This manual is divided into are covering various systems and their electrical Book Three of this manual, the APPENDIX " /e:" ); ,{l' -:' '_

INTRODUCTION ;'

SECTION 1- SYSTEMP¥ii,RVIEW ;, r' ,"': t, ,·, ,. ", " '.

SECTION 2- EQUIPM.ENTFAMI,LIARJZAiJON t" ;:) i A .<'1" :" -'

SECTION 3- •Mor'E' ". "' ,. • ," "",," " ,,'

•

• MOTIQ&ibRIVES::,..", .,"

•

• PLC

SECTION 4- ELECTRIGAL-SCHEMATI.CS OVERVIEW -' I. C. ,,' E Fi Vy'

SECTION 5.:: ,,' '"

SECTION 6-

SECTION 7- 301-M ELECTRICALDRIVE,SYS:fJEM'-'

SECTION 8MODUI£I-OADlNCA1?8OCEt>LmE(;" -:' t " .,:,o ,.

SECTION 9- ELECTRICALSE:TTINGS PIN 206675-1, ,-,.' ·'t, 'p'O"f" ", ' .• " ,I.::.-.::l ('_;."'\0

BOOK TWO: .' ,;

{

SECTION 10- PLC ,. , '(.\'qhEt:. ; "

• [\" PIN

• CGNBtGURATIONS ' PIN '2G@900:0 -'. ! :Jt\ :,:-".

SECTION 11 - :/',,' r) ' : " ", ".,,'t',· "'"

BOOK ONE: ' ,.. '"

• ,"', :',: PIN 269843:1.:

• MJ\CHlNEl1Y'HCUSE Olr,

• ,OPERAT1GRZS' OtT, SAMPLE SCREENS, i' i\ :; -_ ,-. -" "'"" ;-:..,. t' ) "-

BOOK THREE:

APPENDIX - VENDOR INSTRUCTIONS AND PUBLICATIONS

IMPORTANT NOTE

MARION 301-M MINING SHOVEL

ELECTRICAL SERVICE MANUAL

TABLE OF CONTENTS

This manual is divided into major seetions"covering various systems their electrical, components of the Model 301-M electric mining shovel. This Book;Lthe ABPENDI)( contains vendor instructions and publications.

Rotating

Programmable

GEMotors

Instructions

Armored Motors Type MDBOO™

GEH-3258/

SAFETY PRECAUTIONS

WARNING

High voltage and rotating parts can cause serious or fatal injury. The use of electric machinery, like all other utilizations of concentrated power and rotating equipment, can be hazardous. Installation, operation, and maintenance of electric machinery should be performed by qualified personnel, in accordance with applicable provisions of the National Electrical Code and sound local practice.

For equipment covered by this instruction book, itis important to observe safety precautions to protect personnel from possible injury. Among the many considerations, personnel should be instructed to:

• Avoid contactwith energized circuits or rotating parts,

• Avoid by-passing or rendering inoperative any safeguards or protection devices,

• Avoid extended exposure in close proximity to machinery with high noise levels, and

• Use proper care and procedures in handling, lifting, installing, operating, and maintaining the equipment

Safe maintenance practices with qualified perso nel is imperative. Before starting maintenance cedures, be positive that:

• Equipment connected to the shaft will not mechanical rotation,

• Main machine windings have been and secured from all electrical power S011rc:es, and

• All accessory devices associated with the area have been de-energized.

If high potential insulation test is required, dures and precautions outlined in MC-I should be followed.

Failure to properly ground the frame of this chine can cause serious or fatal injury to pe'rS()Olne:r_ Grounding of the machine frame and strucl111'f",tt should be in accordance with Code and consistent with sound local practice.

These instructions do not purport to cover all details orvariations in equipmen t nor to provide for every possible contingency to be met in connection with installation, operation, or maintenance. Should further information be desired or should particular problems arise which are not covered sufficien tly for the purchaser's purposes, the matter should be referred to GE Motors - D\I&G.

© 1991 General Electric Company

GEH-3258/, Armored Motors, Type MD800

LIST OF ILLUSTRATIONS

INTRODUCTION

This instruction book covers the MD800 line of Armored Motors.

WARNING: High voltage and rotating parts can cause serious or fatal injury. The use of electric machinery, like all other utilization of concentrated power and rotating equipment, can be hazardous. Installation, operation, and maintenance of electric machinery should be performed by qualified personnel. Familiarization with NENfA safety standard for construction and guide for selection, installation, and use ofintegral HP motors and generators, National Electrical Code, and sound local practice is recommended.

Installation of the machine where hazardous, flammable, or combustible vapors or dusts presenta possibility of explosion or fire should be in accordance with the National Electrical Code, Articles 500-503, and consistent with sound local practices.

These instructions do not purport to cover all details or variation in equipment nor to provide for every possible contingency or hazard to be met in connection with

Armored Motors, Type MD800, GEH-3258/

installation, operation and maintenance. Should further information be desired or should particular problems arise which are not covered sufficiently for the purchasers' purposes, the matter should be referred to GE Motors - DM&G.

RECEIVING, HANDUNG AND STORAGE RECEIVING

The equipment should be placed under adequate cover immediately upon receipt as packing coverings are not suitable for out-of-doors or unprotected storage. This includes adequate protection from construction dirt, during and after installation.

Each shipment should be carefully examined upon arrival. Any damage should be reported promptly to the carrier and to the nearest office of GE Motors.

HANDliNG

Motors can be lifted by using hooks or slings in the lifting lugs on the frame. These lugs are designed to safely carry the weight of the whole machine. Blowers should be protected with spreader bars if necessary. Ventilating hoods may have to be removed to clear hooks. Do not lift the machine by the shaft extensions. (Refer to the Typical Weights, Table 1.)

*Approximate weights for typical motors in each frame size.

TABLE 1 TYPICAL WEIGHTS*

CAUfrON: Safe practices for lifting and handling equipment should be followed. Hoists and slings should be of adequate capacity and in good repair.

STORAGE

If a machine, or any part of a machine, is not installed immediately, itshould be stored in a clean, dry place and protected from variations in temperature, high humidity, and dust. Ifpossible, sudden changes in temperature and humidity should be avoided. If the temperature of the storage room varies to such an extent that the windings and coils are exposed to moisture condensation, the machine should be protected by a safe, reliable heating system such as space heaters, which will keep the temperature of the machine slightly above that of the storage room. Brushes should not be allowed to remain in contact with the commutator during prolonged storage, otherwise corrosion may occur and later result in flat spots on the commutator, with corresponding poor and destructive commutation.

If the machine has been exposed to low temperatures for an extended period of time, unpacking it before it has reached room temperature will cause it to sweat.

The presence of moisture on the internal machine parts can cause electrical failure of insulated windings and/ or mechanical failure of highly stressed armature glass banding.

All exposed machined steel parts are coated with a rust. preventive before shipment. These surfaces should be examined carefully for signs of rust and moisture, and recoated if necessary. Once started, rust will continue if the surface is recoated wi thout first removing all rust and moisture. Rust may be removed by careful use of fine abrasive paper. Slushing compound can be removed by using a solvent such as mineral spirits.

WARNING: Mineral spirits are flammable and moderately toxic. The usual precautions for handling chemicals of this type should be observed. These include:

A. Avoid excessive contact with skin.

B. Use in well ventilated areas.

C. Take necessary precautions to prevent fire or explosion hazards.

CAUfrON: Care must be taken when cleaning to avoid damaging machined surfaces. Extreme care must be exercised to prevent these parts from rusting since it is difficult, and sometimes impossible, to remove rust from these surfaces without damaging or deforming the surface. Ifbuffs or bumps result from careless handling, carefully remove them using a fine file Or scraper. Machines in storage should be inspected, the insulation resistance should be checked at frequent and regular intervals with an instrument such as a handoperated megger, and a log should be kept of pertinent data. If the log indicates a decreasinginsulation resistance, the motor should be moved to a drier location.

CAUfrON: When stored, the armature must be rotated every three months to prevent loss ofgrease protection on the bearings and races. Loss of grease protection causes rust.

DESCRIPTION

The Type MD800 mill motor series is a complete line of motors, ranging in size from 5 HP to 2,000 HP. They are designed for use as steel mill auxiliaries and for driving power shovels, cranes, hoists, bridges, etc.

Basically the design is the same for all types and sizes, requiring only slight modifications for each particular application. The frames are the horizontal split type with lifting lugs provided on the top half to facilitate installation and removal. On the smaller sizes, horizontal Types MD802 to MD812, the top half is hinged to the bottom half. On the larger sizes of horizontal motors and all vertical types, the top half must be completely removed for inspection, removal, or repair of the armature.

The armature is a complete unit assembly which may be lifted out of the bottom half of the frame, complete with bearing housing and bearing assembly. This facilitates the replacement ofa defective armature in the shortest possible time, in case of failure or breakdown. All standard motors are equipped with a tapered shaft extension at both ends, with a key, nut, and lock washer at each end.

CLASSIFICATIONS

The differen t types of motors for each particular horsepower rating are determined by the system ofventilation used and the method of mounting the motor in service. The types in general use are:

Type MD - Horizontally Mounted, Enclosed

Horizontally Mounted, Force-Ventilated

Horizontally Mounted, Motor-Mounted Blower Unit

Type MOV - Vertically Mounted, Motor-Mounted Blower Unit

Type MDP - Horizontally Mounted, Protected, Self-Ventilated

Horizontally Mounted, Protected, Force-Ven tilated

Horizontally Mounted, Protected, Blower Unit

Type MDT - Horizontally ylounted, Totally Enclosed, Slow Speed, Waterproof Features.

Suffix AE - Single-width solid cylindrical roller bearings both ends.

Suffix AA - Single width solid cylindrical roller bearing pinion end. Single row ball bearing commutator end.

MOTOR BEARINGS

Standard horizontal mill motors are furnished with single width solid cylindrical roller bearings. These bearings are supplied with a single-lipped inner race and double-lipped outer race with the rollers and roller cage retained with the outer race. Armature end play with two roller bearings ranges from 7/64" to 11/64". If these motors are to be operated other than horizontal, a thrust bearing is required at the commutator end of the motor. Suffix "AA" after the motor frame size identifies that the motor is equipped with a thrust bearing at the commutator end.

VENTIIATION

The basic frame design for each motor size provides the necessary openings for self-ventilation, totally enclosed operation, force-ventilation, or external blower unit ventilation.

By the addition or omission of a fan, baffie and covers over the proper openings, each motor can be converted from one type to another.

Armored Motors, Type MD800, GEH-3258/

In a totally enclosed operation, all of the frame openings are closed with solid covers and gaskets, to prevent the entrance of outside air into the motor. The fan continually recirculates the air inside the motor which is isolated from the outside atmosphere. This type is used in wet or dusty locations where the surrounding air would prove injurious to the motor windings and thus affect the operation of the motor.

The self-ventilated protected type motor has deflection hoods assembled over the upper fan end openings to prevent extraneous objects from dropping into the motor. Guards or screens are also bolted to the other openings for the same purpose. Cool air is drawn into the motor through openings at the commutator end of the frame by the armature fan. The air passes over and inside the commutator, circulates between the field coils, flows over and through the armature, and is finally expelled by the fan through openings in the frame at the drive end of the motor.

The MO totally enclosed force-ventilated motor has a rectangular opening in the bottom of the frame on both the commutator and drive ends of frames802 through 818 only. Eitherofthese can be used forthe air inlet. The air discharges through the upper end openings (on the end opposite the air inlet). These openings are covered with special deflection hoods which have hinged flaps inside them. The hinged flaps swing open to allow the air to escape when the motor is being ventilated, and swing closed by gravity to keep out dirt when the ventilation is shut off. All other frame openings are closed with solid covers.

The y[OP protected force-ven tilated motor has the same air inlet as the MO totally enclosed force-ventilated motor. However, in this enclosure, the frame openings in the drive end are covered only with guards so that there are more air outlets.

When air is to be blown into the end opposite the commutator, the armature fan must be removed since it will impede proper air flow.

Motors may also be furnished with a blower unit mounted on the frame. This blower unit is driven by a separate motor mounted on the mill motor. Filters can be supplied with the blower unit if desired, and can be added at any time to a blower supplied without filters. Air outlets are arranged as described above for either the MO totally enclosed force-ventilated motor or the MOP protected force-ventilated motor.

GEH-3258/, Armored Motors, Type MD800

INSTALlATION

WARNING: Installation should be in accordance with the National Electrical Code and consistent with all local codes. Coupling, belt, and chain guards should be installed as needed to protect against accidental contactwith moving parts. Machines accessible to the public should be further guarded byscreening, guard rails, etc., to prevent the public from coming in contact with the equipment.

AllGNl\lENT

CAUTION: Be sure to align or check alignmentcarefully. Misalignmentcan causeexcessive vibration and damaging forces on shafts and bearings. Time taken to assure good alignment will be returned in reduced downtime.

COUPLED DRIVE

WARNING: Disconnect power before touching any internal part. High voltage may be present even when the machine is not rotating. If used with a rectified excitation supply, disconnect all AC line connections to the excitation source. With other excitation supplies, disconnect all DC field connections.

LOCATION

Motors should be installed where they will be readily accessible for inspection and maintenance. Clean, dry air should be available for proper ven tilation of machines which are notequipped for operation with filters, or for separate ventilation from a good source. It is important for all machines that the external openings for ventilation are not obstructed in any manner that might limit the free passage of air.

PROTECTION

CAUTION: Windings, commutators, brush riggings, and bearings should be carefully protected during installation to avoid damage from paint spray, weld splatter, welding rod butts, or metal chips from files and grinders which would fall onto the motor. Metal particles which lodge in windings can cause either immediate or premature failures. Paint or oil on commutators can be detrimen.tal to good commutation.

MOUNTING

Motors should be mounted on rigid and solid foundations. Hold-down bolts should be inspected regularly and kept tight. The feet of the machine may be doweled or blocked to the foundation plates or base when alignment procedures are completed.

When a motor and a driven unit together have four or more bearings, flexible couplings should be used to facilitate alignment. Three-bearing construction requires a rigid coupling. Careful alignment of machines when using either solid (rigid) or flexible couplings is essential to preven t excessive vibration, hot bearings, or shaft failures.

INSTALLATION ADVICE FOR MDT TABLE MOTORS

CAUTION: Operating conditions where highpressure water and mill scale directly strike the shaft and bearing seal must be avoided. Increased protection for the bearing assembly can be provided by installing a collar over the coupling hub as shown in Fig. 1. The collar is designed to have a close-running clearance \\'1th the outside diameter of the bearing cartridge. Physical barriers can also be installed to provide increased protection for the bearing assembly. The need for additional protection is best determined by the mill builder and customer, who have knowledge of the motor environment. Precautions taken to protect the motor bearings from contamination will pay dividends in increased bearing life and reduce downtime for the motor.

OPERATION

WARNING: High voltage electric shock can cause serious injury. Disconnect power before touching any internal part. High voltage may be presen t even when the machine is not rotating. Ifused with a rectified power supply, disconnect at! AC line connections to power supply. \I/ith other power supplies, disconnect all DC line and field connections. Also disconnect power from auxiliary devices.

WARNING: Ground the machine properly to avoid serious injury to personnel. Grounding should be in accordance with the National Electrical Code and consistent with sound local practices.

INSPECTION BEFORE STARTING

These inspection procedures should be followed before starting the machine for the first time, after an extended shutdown, or after a teardown for extensive maintenance or repair.

Bearings

Ball or roller bearings are greased at the factory and will need no attention until relubrication is necessary as suggested in the Maintenance section.

Make sure that all grease plugs are tight.

The bearings on the MD828 are insulated from ground.

To preclude the possibility of the shaft operating at a potential above ground, the bottom bolt on the drive end bearing assembly is utilized as a grounding bolt. To check the insulation resistance, remove the grounding bolt and measure the shaft to ground resistance. If readings are less than :?O,OOO ohms, the exposed surfaces of the insulation may be coated with oil and dirt causing a short. Cleaning these surfaces should prod !lce satisfac-

21.

tory readings. Persistently low readings may be caused by dirt or metal chips imbedded in the sheet insulation or insulated bolt assemblies.

Insulation

Take and record megger readings to determine ifmoisture or dirt are present on winding surfaces. The readings for indoor storage should be taken monthly. Any downward trend of the megger readings indicates appropriate maintenance steps are required. (Refer to the Insulation Resistance Measurement and Cleaning of Windings section of this Instruction Book.)

Commutator and Brushes

Brushes should be worn in to have at least 85 percent contact over the brush surface and continuous contact from heel to toe. The commutator surface and undercut mica should be clean and free from dirt, grease, paint spots, or brush dust.

Check all brushes to be sure they are free to move in the holders. All springs should be down and latched. Brush pigtail connections should be tight and the pigtails should not interfere with the action of the spring or brush, and should not contact any object that does not operate at brushholder potential.

Connections

All terminal connections should be checked against the motor's connection diagrams to be certain that the polarity or direction of rotation will be correct.

Fig. 1 Shaft and Bearing Seal

GEH-3258/, Armored Motors, Type MD800

See that bolted connections are tight, adequately insulated, and that proper clearances exist between conductors of different polarity and between conductors and ground. Bolted connections of flexi ble cable should be insulated.

Shunt Field Excitation

For many MD motor applications, it is common practice to leave the shunt fields excited while the motor is in a standby mode.

The shunt fields for the shunt, compound, and stabilized shunt motors have the capability of being energized continuously at standstill with rated voltage without exceeding rated temperature rise. Motors applied with field forcing must have cooling air supplied when the fields are overexcited. In the event ofloss of cooling air, the shunt field excitation must be reduced to rated or below. It is recommended the air supply be interlocked to provide this protection.

MDP motors used on excavators are normally applied with field forcing on a duty cycle basis. It is important that the blowers be on and running in the proper direction when the fields are energized. Self-ventilated excavator motors, when at standstill, must have the excitation reduced to approximately 60 volts on the nominal 72 volt field.

Protective Devices

WARNING: See that all protective devices (overspeed devices, bearing temperature relays, etc.) are connected and will function properly. Be sure all coupling guards, shaft protectors, grounding connectors, covers, and other safety devices are properly attached.

Space Heaters

Space heaters are furnished in machines when ordered. They should be energized \\'ith the correctAC voltage as shown on the nameplate.

WARNING: The surface of a space heater block becomes hot when the heater is energized. The temperature rise above the ambient temperature may be as high as 400·C. Avoid touching heater blocks when heaters have been recen tly energized to preven t bu ms. Also ignitable dust or lint should not be allowed to collect around the surface of the heaters to prevent fire or explosion.

Speed Limit Device

The mechanical speed limit device is factory adjusted to trip at 115 percent (± 2 percent) of rated top speed and requires manual resetting.

Both normally open and normally closed contacts are present and have current ratings as in Table 2.

TABLE 2

SPEED LIMIT DEVICE - MAX. CURRENT RATINGS

NORMALLY OPEN OR CLOSED CONTACTS

Thennostats

The thermostat is a protective device. It is not intended to limit motor loading or provide normal insulation life. When supplied, it is mounted in contact with a commutating coil, which is the only accessible part of the armature circuit. Since factors such as shaft speed, ventilation (blower orshaftfan), currentripple (SCR phaseback), and short time overload affect the temperature relationship between the armature and commutating field, complete protection from all conditions resulting from overtemperature is not possible. The device is especially useful in guarding against loss of normal ventilation air, high ambient temperature, and prolonged operation of self-ventilated motors at very low speeds.

Thermostats may be used in alarm or relay circuits within rating limits shown in Table 3.

TABLE 3

THERMOSTAT - MAXIMUM CURRENT RATINGS

NORMALLY OPEN OR CLOSED CONTACTS

LOAD 1125 VAC 1250 VAC 1600 VAC 130 VDC

DO NOT USE ABOVE 600 VAC or 30 VDC

Resistive 5 amps 2.5 amps 1amp 5 amps

"Inductive 3 amps 1.5 amps 0.5 amps 1.5 amps

"Suitable for Pilot Duty only (Relay coils).

WARNING: Thermostats automatically reset after the motor has cooled somewhat. In order to prevent property damage or injury to personnel, the control circuit should be designed to prevent the automatic starting of the motor when the thermostat resets.

Ventilation System

See that blowers or central systems are ready to supply cooling air.Air filters should be in place. Blowers should be checked for correct rotation.

General Mechanical Inspection

Check the inside of the machine for tools, metal chips, or any other foreign material that may have accumulated during storage or installation. Make sure that all rotating parts have enough clearance from any stationary parts. Turn the machine over by hand, if possible, and check for scraping noises or any other signs of mechanical interference. Check the tightness of the bolts in the feet, couplings, frame split, bearing housings, and any other bolts that may have been disturbed.

TABLE 4

Tightening Bolted Joints

CAUTION: Special instructions apply to bolted joints from "Z" vintage vertical motors in frames MDV804 through MDVSOS. For "Z vintage" motors identified by "Z" in the model list, refer to Instruction Book GEH-4246. Special instructions also apply to "Z"vintage horizon tal excavator MDP806 through 812 motors per GEH-428i.

Since loose bolts can cause both electrical and mechanical failures, all bolts and nuts must be kept tight. Maintenance schedules must include the checking of bolt tightness. Table 4 gives the torque values to be used in this maintenance procedure.

The information in Table 4 applies to all bolted joints except when non-metallic parts (e.g., fluid bed parts, polyester glass moldings) are bolted to metallic parts. Here, lower torque values as listed in Table 5 are recommended to prevent parts from fracturing.

GEH-325B/, Armored Motors, Type MDBOO

TABLE 5

BOLT TIGHTENING TORQUE VALUESNON-METALLIC PARTS TO METALLIC PARTS

Hex Head C1C5 Medium Carbon Steel (Yokes, Brush Studs, Coil Supports)

The following precautions which apply to the tightening of bolted joints should be observed in maintenance procedures:

(l) Use a torque wrench for tightening onlv. When necessary to loosen bol ts, use another type ofwrench.

(2) The pressure bearing surfaces and the threads of nuts and bolts should be clean, dry, and free from oil and grease when torqued to the values given. Oiled threads require that torque values be reduced 10 percent.

(3) When initially tightening a bolted joint, the final turn must be tightened with the torque wrench to obtain an accurate setting.

(4) In checking the tightness of boltedjoints, the torque wrench should be applied at the higher value of torque given in the Tables to ensure adequate tightness.

Loose pole bolts will cause serious failures on industrial equipment. Even though all of these pole bolts are torqued to the specified values during manufacture, they must be checked on site periodically. Experience has shown that bolted joints are subject to loosening during shipping. Experience has also shown that both vibration and heating and cooling of bolted join ts cause them to loosen.

For these reasons, the pole bolts should be checked according to the recommendations below:

(1) Before start up, make a visual inspection and spot check of main and commutating pole bolt tightness with a torque wrench.

(2) After 24 hours of service is complete, all main and commutating pole bolt torques should be checked.

(3) After three months of service, again check all main and commutating pole bolt torques.

(4) Then, every six months or as often as experience dictates, check all main and commutating pole bolt torques.

NOTE: It may be difficult to use a torque wrench on some pole bolts due to machine location or mounted accessories. A good method of checking the torque on these bolts is to first get the feel of the desired torque with a torque wrench on an accessible bolt. Then, immediately check the difficult bolt using a normal wrench with approximately the same lever arm. Most mechanics will come within 10 percen t of the desired value.

INSPECTION AFTER STARTING

The following items should be checked after the machine is running:

WARNING: Avoid contact with moving or electrically hot parts. When working with rotating electrical machines, avoid wearing loose sleeves, neckties, wristwatches, or rings.

Bearings

Place thermometers on all bearing housings so that bearing temperatures can be watched for a few hours. Ball or roller bearing housing temperatures should be no more than 25°C (45°F) above room temperature or a maximum of 65°C (149°F). Higher temperatures than this indicate trouble. Check alignment and lubrication. Do not overgrease.

Noise and Vibration

Check for unusual vibration or noises that might indicate rubbing or interference. New machines may smell warm or have the odor of varnish, bu t should not smell scorched.

Vibration of new machines should not exceed 0.002" (.05 mm.) at the bearing houses. The most likely cause of vibration in new machines is misalignment due to improper installation, loose foot bolts, uneven shimming under feet, or damage to the machine during shipmen t or installation. Current ripple due to rectified power supply may also be a source of vibration and audio noise.

BEFORE PUrrING MACHINE IN SERVICE

Run at light loads or at no load for a few hours to determine that no unusual bearing temperatures occur, that no localized electrical heating results, and (in the case of machines with unseated brushes) that the brushes get the proper fit. Be sure that any carbon dust resulting from brush seatings is cleaned up before full-load operation. Check for satisfactory commutation when load is first applied.

INSPECTION AFTER SHORT TUvfE IN SERVICE

After a machine has been operating for a short time, an inspection should be made to ascertain that there have been no changes since installation. Check for increased vibration, signs of change in alignment or foundation settling, bolts that may have loosened, rubbing parts, loose connections, and worsened commutation. Take the proper steps to correct the trouble.

MAINTENANCE

WARi.'lING: High voltage electric shock may cause serious or fatal injury. Disconnect power before touching any internal part. High voltage may be present even when the machine is not rotating. If used with a rectified power supply, disconnect all AC line connections to power supply. With other power supplies, disconnect all DC line and field connections. Also, disconnect power from auxiliary devices.

WARNING: Ground the machine properly to avoid serious injury to personnel. Grounding must be in accordance with the National Electrical Code and consistent with sound local practices.

Armored Motors, Type MD800, GEH-3258/

that maintenance operations which do not more than pay for themselves are notjustified. Such a case would be where more money is spent on the maintenance than would be saved if the equipment were not maintained and allowed to fail.

Contact your nearest GE Service Shop or I&SE office to get printed material describing ways of setting up a Productive Maintenance system.

Productive Maintenance as applied to MD800 Armored Motors would mean:

(I) Making good records of machine data and setting up a means of recording maintenance performed and measurements taken.

(2) Establishing a routine of measurements to be taken and inspection operations to be performed. Without other experience to guide you, follow the suggested maintenance schedule given later. Experience can be quickly built up by performing the inspections and measurements called for. These records will show you whether or not various components of the machine change quickly or slowly. \laintenance schedules can then be re-adjusted as this experience dictates. Making more frequent and more elaborate inspections at first and carefully recording results will give a feel for the important items and the timing of critical inspection items. Set up a program to balance between spending more on maintenance and inspection than a failure would cost.

In some cases, it is less expensive and will do no harm to repair or replace a part after it wears out rather than maintain it regularly. Equipment the size and value of an \ID800 Armored Motor will justify a certain amount of routine maintenance.

WARNING: Replace covers and protective devices before operating.

PRODUCTIVE MAINTENANCE

Productive Maintenance goes a step beyond preventive maintenance techniques. Productive Maintenance means that maintenance should pay for itselfin terms of less downtime, money saved in repairing equipment, and more total production for each dollar spent on maintenance operations. Productive :vlaintenance means

Accurate records will help form your judgment of what is important and will also show gradual aging of the insulation, wear of brushes, loosening offastenings, and roughening of the commutator. These records will also point out the approaching need for repair or replacement of components.

The Suggested Maintenance Schedule on the next page shows a suggested schedule of routine maintenance operations and measurements. A time schedule is given which may be modified as a record of experience is built with this equipment in particular applications. Motors on continuous process lines will have more operating hours than intermittently run machines and will need more frequent attention.

GEH-325B/, Armored Motors, Type MDBOO

SUGGESTED MAINTENANCE SCHEDULE

Adjust this schedule as necessary. Be guided by your records. They will show when more or less attention is justified.

COMPONENT BEARINGS

Ball and Roller

INSPECTION OR MAINTENANCE OPERATION MONTHLY

Make sure that grease or oil is not leaking out of the bearing housings. Ifanyleakage is present, correct the condition before continuing to operate.

Listen to a few bearings on a sampling basis. Bearings that get progressively noisier will need replacement at the next shutdown. Regrease if called for under Frequency of Lubrication.

BRUSHES

Check the brush length. Replace when the brush wear marker on the pigtail reaches the top of the brush box. Inspect for worn or shiny brush clips, frayed or loose pigtails, chipped or broken brushes, and check for indications of overheating of the brush or pigtail at the socket. Remove a few brushes to check the brush-commu tator contact face. Burned areas indicate commutation troubles. Loosen each brush in its holder. Blowout the area of the brushholder and brushholder stud insulation with clean, dry air to get rid of brush dust. Wipe brushholder stud insulation to remove contamination.

WARNING: High voltage and rotating machinery can cause serious or fatal injury. Brushes must not be touched or replaced while the machine is energized or rotating.

COMMUTATORS

Check the commutator for roughness by carefully feeling the brushes with a fiber stick.] umping brushes give advance warning of a comm u tator going rough. Observe the commutator for signs of threading. (Refer to the Commutator Check Chart, GEA- 7053 which is included as part of this Instruction Book.) If threading is getting wor.se, take action; threading healed over - OK. Check for excessive commutator wear rate, streaking, copper drag, pitch bar-marking, and heavy slot bar-marking. Commutator should not have more than 0.0025" (.06 mm.) total indicator runout or 0.0002" (.005 mm.) bar-to-bar steps.

INSUlATION

MECHANICAL

Air Filters

Bolts

Noise and Vibration BEARINGS

Ball and Roller

Perform a visual inspection. (Refer to the Insulation section of this Instruction Book.)

If supplied with motor, keep in good working order. Replace when necessary.

Perform visual observation for loose bolts, loose parts, or loose electrical connections. Check pole bolt torque. (Refer to Tables 4 & 5 for correct torque values.)

Check for any unusual noise, vibration, or change from previous observations.

EVERY SIX MONTHS

Listen to all bearings.

(Continued on next page)

COMPONENT COMMUTATORS INSUlATION

SUGGESTED SCHEDULE (CONT'D)

INSPECTION OR MAINTENANCE EVERY SIX MONTHS (Cont'd)

Check risers for cracks and dirt. If there are cracks, also check end of shaftke}'Way and shaft fan. (Cracks in this area mean extreme torsional vibration in system.) Dirt should be cleaned out of the risers to maintain good ventilation.

Measure one-minute insulation resistance. (Refer to Insulation.) Compare with records. Wipe deposits from brush holder stud insulation and commutator creepage path. Remove heary deposits from around the field coil connections where grounding might occur. Blow deposits out of the commutator riser area with clean, dry air. Blowout any blocked ventilation openings in windings. Make visual inspection for signs of overheating (dry, cracked, "roasted-ou t" insulation and varnish).

MECHAi.'lI CAL Bolts

Check all electrical connections for tightness. Look for signs of poor connections (arcing, discoloration, heat). Adjust inspection period to suit experience. Inspect foundation for signs of cracking, displaced foot shims; check foot bolts for tightness. Check frame-split brushholders, brushholder studs, bracket bolts, etc., on sampling basis. Check all coupling bolts. Check pole bolt torque. (Refer to Tables 4 and 5 for correct torque values.)

Shaft

Ventilation Vibration

Check corners of exposed end of shaft keyway for cracks (due to extreme torsional vibration). If there are cracks, check fan and commutator risers.

Check for clogged screens, louvres, filters, etc.

Check for excessive vibration (more than 0.002" to 0.003") (.05 mm. to .08 mm.) that will indicate change in balan ce or align men t. (Referto Noise and Vibration.)

NUUNTENANCEPROCEDURES REPAIR

Repairs should only be made by qualified personnel using the materials and processes for which the motor was designed. To protect the warranty during the warranty period, all repairs must be made in a GE Service Shop or approved repair facility. Many repairs can be easily performed with only assembly operations, if GE replacement parts are available. If major repairs are undertaken (such as rewinding an armature), proper facilities should be available and suitable precautions observed.

WARNING: When burning off old insulation materials or when welding near insulation during rewinding, adequate ventilation must be provided to avoid exposing personnel to noxious fumes. Combustion of exhaust fumes must be complete and adequately vented to the outside atmosphere.

WAR.:.'iING: Exposure of personnel to airborne inorganic fibers must be avoided by adequate ventilation or by wetting the remaining insulation cornponen ts following the burning off of the organic materials.

FAILURE

WARNING: An extreme overload or electrical failure may result in heating or arcing, which can cause the insulation to give off noxious fumes. All power should be removed from the motor or generator circuit as a precaution even though the circuit has overload protection. Personnel should not approach the motor or generator un til adequate ven tilation of the area has purged the air offumes. When covers of a motor or generator are removed after a failure, care should be observed to avoid breathing fumes from inside the motor or generator. Preferably, time should be allowed for the motor or generator to coot before attempting any examination or repair.

Removal of Armature

CAUTION: Safe practices for lifting and handling equipment should be followed. Hoists and slings should be of adequate capacity and in good repair. (Refer to Table of Weights, Table 1.)

In the smaller sizes, Types MD802 through MD812, the top half of the frame is hinged to the lower half. Therefore, it is only necessary to open it to remove the armature. (Refer to Fig. 5.) In the larger sizes, the top half must be disconnected, unbolted, and lifted off before the armature can be removed. On all units, care should be taken so that the bearing cartridge does not slide off the shaft during handling.

WARNING: Water should not be applied to any electrically energized equipment, because electric shock could result in serious or fatal injury. In case offire, disconnect all power and use a carbon dioxide extinguisher to quench the flame. Before operating any motor or generator after a suspected failure, it should be inspected for damage. Remove covers and make visual inspection of brushes, commutator, connections, and windings. Electrical tests of each winding to check for open or short circuits or grounds should be made. Any arc damage should be cleaned up and repaired as necessary. Brushes may need reseating before operation.

- HORIZONTAL MOTOR

Clean exterior before starting disassembly.

Refer to Fig. 2, which is a t)pical longitudinal section through the armature and bearings of the horizontaltype motors.

Figs. 3 and 4 show typical longitudinal sections through the armature and bearings of the MD820 through MD828 horizontal-type motors.

In these motors, the armature, (with bearings and bearing housings assembled) forms a complete unit assembly which can be readily removed or installed in the frame assembly. The correct bearing alignment is maintained by the mounting bolts. The bolts secure the bearing housings, which have machined surfaces as part of the frame.

(1) Remove the bolts which clamp the two frame halves together and the bolts which clamp the bearing housings to the top frame half. Remove the brushes from the holders to prevent brush breakage.

(2) On motors with hinged frames, hoist the top frame half rotating it on the hinge approximately90', and secure itin this position. On motors without hinged frames, disconnect the external cable connections between the two halves of the frame and hoist the top frame half directly up and then away from the motor.

(3) If the armature is to be removed, remove the bolts which hold the bearing housings to the bottom half of the frame, loop a rope sling around the two shaft extensions, and carefully lift the armature avoiding damage to field coils and other parts. Place the armature on a support to the shaft, bearing housings, or core to hold it off the floor.

The MD820 through MD828 motors are designed with com pensating windings. Before removing the top half of the stator frame, it is necessary to disconnect the compensating or pole face connections, bus ring connections, and brush rigging yoke internal to the stator frame. For a typical view of electrical connections at the frame split, refer to Fig. 6.

Removal of Bearings (Refer to Fig. 2)

(I) The bearing housing assembly with outer race and rollers of the bearing can be readily pulled offofthe shaft for inspection or disassembly. Note that these roller bearings have a double lip on the outer race and a single lip on the inner race, which must be assembled on the shaft with the single lip on the armature side. This permits the roller assembly to be pulled off of the inner race without any further disassembly.

(2) To remove the bearing assembly, puIl the bearing cap and cartridge assembly, including the outer race and roIlers, from the shaft.

(3) Heat the thrust coIlar and the inner race of the bearing to approxi mately 100' C and remove from the shaft, using a puller which engages on the end of the thrust collar. (Fig. 8 illustrates the method of using the puIler.)

Care should be taken not to damage the commutator shell insulation.

Removal of Shaft From Annature

The armature core and commutator are pressed on the shaft. If it becomes necessary to replace a shaft, remove the bearings as described earlier. Remove the fan hub in a similar manner. Then, obtain a steel pipe or sleeve which will just fit over the shoulder on to the shaft at the drive end and long enough to press the armature core

(Photo No. MG5295)

910

10. SHAFT

16. PINION NUT

17A. LOCKWASHER

31. BEARING

34. BEARING CAP

36. BEARING CARTRIDGE

39. THRUST COLLAR

910. CAP SCREW

150. FRAME

Fig. 2 Type MD808 Bearing Parts

Fig. 3 Type MD820 Through MD824 Section

GEH-3258/, Armored Motors, Type M0800

(Photo No. MG5292·1)

Fig. 5 Type MD808 With Top Half Opened For Removal of Armature

and commutator off of the shaft. Support the armature on this pipe so that the pressure is exerted on the shaft at the commutator end. Protect the end of the shaft when pressing. (Refer to Fig. 9.)

The pressing tonnage for shaft removal will normally range between 10 tons (9000 kilograms) and 200 tons (180,000 kilograms). It is likely that damage may result to the commutator end shaft extension in this operation. Usually the shaft is being replaced so this damage is of no concern. If required, the damage to the shaft threads can be minimized by using a shaft nut to distril>ute the load.

Heating of the armature in an oven to approximately 150'C before pressing will usually reduce removal tonnage to be within the above range.

Removal of Brushholder

Each brushholder is individually bolted to a support which is bolted to the motor frame. To remove a brushholder, disconnect the brush pigtail and loosen the bolt sufficiently to remove the brushholder.

Removal of Field Coils

(1) Lift or remove the top half of the frame as described under Removal of Annature.

(2) Disconnect the cables to the coil to be removed, and take out the bolts which hold the pole piece to the frame. Remove the complete pole piece and coil assembly. In order to remove some coil and pole assemblies, it is necessary to remove the adjacent poles first. The armature must be removed from the frame for proper access to coils and poles in the bottom frame half.

(3) When removing connections and coils, take care to prevent bumping coils and terminals which can result in damage to the coil coating. Reassemble bolts, washers, and nuts on coil terminal.

NOTE: Do not dislodge or otherwise damage insulation washers molded between coil terminals. Do not lose insulation bolts for field coil terminations.

ASSEMBLY - HORIZONTAL MOTOR

Installing Field Coils (Annature Removed)

(1) Always assemble the bottom center commutating coil first, since it cannot be inst.alled if the two adjacent exciting poles are in the frame.

Armored Motors, Type M0800, GEH-3258/

(2) Assemble the pole piece and coil assembly into the frame and secure it with bolts through the frame. It is recommended that new lock washers be used on the pole piece bolts when reassembling the field coil in the frame. Draw the bolts up tight to seat the pole piece in the posi tion on the frame. For motors with compensating windings, Fig. 7 illustrates the brazed type connections. Fig. 7B illustrates how to assemble the bolted type pole face connections. (Refer to the Reconnection of Pole Face Assemblies section for connection and post treatment of pole face windings.)

(3) Tie all cables into neat sturdy bundles. Tie cable bundles to cable anchors in the frame so that bundles are suspended securely in position. Locate cable bundles away from sharp corners, moving parts, brush rigging, and hand hole openings.

(4) Insulate all internal bolted coil connections as described below:

A) Apply a small amount of insulating putty as required to smooth sharp corners and fill all voids to round out the joint for easier taping.

B) Apply tape. Several lengths may be used, but start each length so that one or more full turns of tape secure previous tape end.Joint insulation taping should completely cover the bolt, nut, washers, terminals, etc., extending approximately 1/4" to 1 /2" mm.) onto the cable and/or lead insulation, resulting in at least 3 tape thicknesses minimum coverage.

C) Paint the tape surface with fast-drying insulating varnish.

Assembly of Brushholder

(1) Install the brushholderon the support as high offof the commutator as possible. Tighten the bolt sufficiently to hold the brushholder in place until after the frame is closed on the armature. Remove brushes from the brush holders to prevent brush breakage when the armature is installed.

(2) After the frame halves have been assembled in place together with the armature, release the bolt and adjust the brushholder to provide .070" to .080" (1.8 to 2.0 mm.) clearance between the face of the brush holder and the commutator surface. An .075" (1.9 rnrn.) thick non-metallic shim may be used. Tighten the bolts securely.

GEH-3258/, Armored Motors, Type MD800

(Photo No. MG51JO-8)

Fig. 6 Compensating Winding Connections At Frame Split

NOTE: Parts 4, 5 and 6 to be tightened to 17 pound foot (23 newton-metre) torque.

(Photo No. MG5269-1j

Fig. 7B Typical Bolted Pole Face Connection

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