8KatoGenerator.pdf

INSTRUCTION MANUAL

FOR

NATIONAL

OCEANIC

ATMOSPHERIC

ADMINISTRATION

92956

SERIAL NUMBER

Kato Engineering, Inc.

, .. ,~lllRTIFIS~ . ·.

P.O. Box 8447 Mankato, MN 56002-8447

(507) 625-4011 Fax (507) 345-2798

MAINTENANCE

SCHEDULES

PUBLICATION NUMBER 352-23009-00

PUBLICATION DATE: June 97

KATO MOTOR, GENERATOR, OR MOTOR

GENERATORS (SYNCHRONOUS OR INDUCTION)

Kato Engineering Inc.

ce-.,W1t1Co •.

1509001'

P.O. Box 8447 Mankato, MN 56002-8447

Fax(507)345-2798

Contents

THE SIGNIFICANCE OF MAINTENANCE

SERVICE CONDITIONS REDUCING INSULATION LIFE .. 4

VISUAL INSPECTION METHODS ················••u••--·············· 5

INSULATION MAINTENANCE TESTS

INSULATION RESISTANCE TESTS AT LOW VOLTAGE

CLEAN I NG INSTRUCTIONS ...............•................... ·•• • nmma • aa • 8

FIELD SERVICE CLEANING - ASSEMBLED MACHINES

FIELD SERVICE CLEANING • DISASSEMBLED MACHINES

MAINTENANCE SCHEDULES

DAILY CHECKS

EVERY 2000 HOURS OR 6 MONTHS OF OPERATION ............................................... , ••••• 9

EVERY 8000 HOU RS OR YEARLY

EVERY 20,000 HOURS OR 3 YEARS

EVERY 40,000 HOURS OR 5 YEARS

THE SIGNIFICANCE OF

Rotating electric machines are complex structures that are subjected to mechanical, electrical, thermal and environmental stresses of varying magnitude. Of the various components, the insulation systems are the most susceptible to aging or damage due to these stresses. The service life of an electric machine will, therefore, largely depend on the serviceability of the insulations systems. Adequate inspection and testing programs are advocated to assure that the equipment is maintained in satisfactory condition to minimize the possibility of in-service failure.

A regular maintenance and inspection program can provide an evaluation of the present condition of the equipment and indicate potential long term prob lems. The extent to which a maintenance program is pursued will depend on application, environmental c:onditions, and the operator's own experience and philosophy. A regular maintenance program involv ing periodic disassembly and knowledgeable visual examination of the equipment, together with the application of electrical tests is strongly recom mended. It should be recognized that over potential tests can damage insulation that is contaminated or in marginal condition. Where there is uncertainty, refer to I.E.E.E. Standard 432-1992 or consult with Kato Engineering Co.

SERVICE CONDITIONS

REDUCING INSULATION

LIFE

Electric machines and their insulation systems are subjected to mechanical, electrical, thermal and environmental stresses that give rise to many deteriorating influences. The most significant of these are the following:

THERMAL AGING: This is the normal service temperature deteriorating influence on insulation.

OVER-TEMPERATURE: This is the unusually high temperature of operation caused by conditions such as overload, high ambient temperature, restricted ventilation, foreign materials deposited on windings or winding faults.

OVERVOLTAGE: This is an abnormal voltage higher than the normal service voltage such as caused by switching or lightning surges. Operating above rated nameplate voltage will reduce insulation life.

CONTAMINATION: This deteriorates electrical insulation by conducting current over insulated surfaces or by attacking the material reducing electrical insulation quality or physical strength or by thermally insulating the material that causes the material to operate at higher than normal tempera tures. Such contaminants include the following:

(A) Water or extreme humidity

(8) Oil or grease including unstable anti-wear and extreme pressure lubricants

(C) Conducting and nonconducting dusts and par ticles

(D) Industrial Chemicals such as acids; solvents and cleaning solutions.

PHYSICAL DAMAGE: This contributes to electrical insulation failure by opening leakage paths through the insulation. Physical damages includes the following:

(A) Physical shock

(B) Vibration

(C) Over-speed

(D) Short-circuit forces or line starting

(E) Erosion by foreign matter

(F) Damage by foreign objects

(G) Thermal cycling

IONIZATION EFFECTS: Ionization (corona), which may occur at higher operating voltages is accompa nied by several undesirable effects such as chemical action, heating and erosion.

VISUAL INSPECTION

METHODS

To achieve maximum effectiveness, a visual inspec tion program should be directed initially to those areas that have been shown by previous experience to be most prone to the forms of damage or degrada tion caused by the influences listed. The most suspect areas for deterioration or damage to which inspection should be directed are:

GROUND INSULATION:

Ground insulation is generally defined as that insulation intended to isolate the current carrying components from the noncurrent bearing compo nents.

SUPPORT INSULATION:

Support insulation, such as block, slot wedges, etc.

are usually made from compressed laminates of fibrous materials, polyester or similar felt pads impregnated with various types of bonding agents.

DETERIORATION OR DEGRADATION OF INSU

LATION FROM THERMAL AGING:

Examination of coils reveal general puffiness, swelling into ventilation ducts or a lack of firmness of the insulation, suggesting a loss of bond with conse quent separation of the insulation layers from them selves or from the winding conductors or turns.

ABRASION:

Coil and connection surfaces may be damaged by abrasion or contamination from other sources, such as chemicals or abrasive or conducting substances.

CRACKING:

Cracking or abrasion of insulation may result from prolonged or abnormal mechanical stress. In stator windings, looseness of the bracing structure is a certain guide to such phenomena and can itself cause further mechanical or electrical damage if allowed to go unchecked.

EROSION:

Erosion may be caused by foreign substances impinging against coil insulation surfaces.

INSULATION

MAINTENANCE TESTS

Insulation tests are conducted for two reasons:

(1) To discern existing weakness or faults

(2) To give some indication of expected service reliability

INSULATION RESISTANCE TESTS AT

LOW VOLTAGE

These tests are usually made on all or parts of an armature or field circuit to ground. They primarily· indicate the degree of contamination of the insulating surfaces .or solid insulation by moisture and other conducting influences and will not usually reveal complete or uncontaminated ruptures.

Insulation resistance tests are based on determining the current through the insulation and across the surface when a direct voltage is applied. The current is dependent on the voltage and time of application, the area and thickness of the insulation and on temperature and humidity conditions during the test.

The insulation resistance test is used to determine the insulation condition prior to application of more extensive testing measures. Refer to the following electrical measurement procedures for testing detail.

Contact Kato Engineering or refer to I.E.E.E Std.

432-1992 when more extensive insulation tests are required.

Exciter Field (Stator)

1. Disconnect the exciter leads from the terminals in the terminal box.

2. Connect exciter leads to one clamp of 500 volt megger and connect the other clamp to the machine frame.

3. Apply 500 volts from the megger and measure the resistance reading after one minute. The minimum reading should be 1.0 megohm. If not, refer to dry out procedures.

4. Short the exciter field leads to the machine frame for several minutes after the megger has been disconnected. This will allow the voltage build up to be properly discharged.

Exciter Armature

1. Disconnect the exciter armature leads from the rotating rectifiers. Disconnect the machine field leads from the positive and negative rectifier heat sinks.

2. Never apply megger to rotating rectifiers. Connect the leads of exciter armature to one clamp of a 500 volt megger and connect the other clamp to suitable connection on the shaft.

3. Record the megohm reading after one minute of applying 500 volts

4. One minute reading mu.st be a minimum of 1 megohm. If not, refer to dry out procedures.

5. Ground the exciter leads to the shaft after discon necting the megger.

Machine Rotor Winding

1. Connect the positive and negative leads to one clamp of the 500 vo!t megger and connect the other clamp to the shaft.

2. Record the megohm reading after one minute of applying 500 volts.

3. One minute reading must be a minimum of 1 megohm. If not, refer to dry out procedures.

4. Ground the field leads to the shaft after discon necting the megger.

Machine Stator

1. Disconnect power connections and all control apparatus from the machine terminals.

2. Measure insulation resistance of each phase separately with the two other phases shorted to the frame.

3. Use a 500 volt megger connected between the lead of the phase to be measured and machine frame.

The minimum one minute insulation resistance (corrected to 40° C) should not be less than that given by the following formula:

Resistance in megohms= Rated machine voltage +1000

If less than above, refer to dry out procedure.

4. Ground the leads to the frame after the one minute megger test.

NOTE: The insulation resistance value increases with decreasing winding temperatures. All readings must be referenced to winding temperatures. Use Figure 1 for converting megger readings to other temperatures.

Drying Methods

If the insulation resistance readings are below the recommended minimum values specified previously, use one of the dry out methods described below. The method selected should be based on the size and location of the unit, and available equipment with experienced personnel.

Remove voltage regulator and cover all inlet and clischarge openings. Provide an opening at the top of the machine, preferably at the fan end, for moisture to evaporate. Monitor winding temperatures. DO NOT APPLY HEAT TOO RAPIDLY. Winding temperature should be raised gradually at a rate of 10° C per hour up to 93"C (200°F). Measure insulation resistance at one hour intervals. Typically the insulation resistance will slowly drop while the temperatuie is coming up, and then gradually increase and level out.

J)

D I . ' . ' 0 • . )

• J

I

V

FACTOR FOR CONVERSION TO •o·c

I I I " ,- Enmpt.: I

I 100 m~ohms me• sure-d • t 1 s •c.

i- Find m190hms 11 40°C .

ConwetJ1on t• c1ar • l I ~ IS"C. is .27. so

!/ me;ohms &I 4O"C.

is 27 l.27 1 100).

V I , I I

J

I I

V

V / Eumple:

/ 100 megohms measured I/ at 50°C. Find megohms

I at 4o•c. Conve,s.ion lac1or

I at SO'C. ls !.7. so megohms at 40• C ;, 17011.7 1100).

IC, JO ]O oiO" ~ l£l 10 II) 'Cl IO('I 110 IXJ •10 IIQ 1',,!

T-emperalure - •C

Figure 1

CLEANING INSTRUCTIONS

Proper maintenance of electrical equipment requires periodic visual examination of the machine and windings and appropriate electrical and thermal checks. Insulation surfaces should be examined for cracks and accumulations of dirt and dust to deter mine required action. Lower than normal insulation resistance can be and indication that conductive contaminant is present. The contaminant may be carbon, salts, metal dusts or virtually any dirt satu rated with moisture. These contaminants develop a conductive path to produce shorts or grounds with subsequent failure. Cleaning is also advisable if heavy accumulation of dirt and dust can be seen or are suspected to be restricting ventilation as mani fested by excessive heating.

Caution:

Without visual, electrical or thermal evidence that dirt is present, cleaning should not be initiated since unnecessary winding deteriorat ion may occur.

If harmful dirt accumulations are present, a variety of cleaning techniques are available. The one selected will depend on;

(1) The extent of the cleaning operation to be undertaken

(2) The type of enclosure and the voltage rating of the machine involved.

(3) The type of dirt to be removed

FIELD SERVICE CLEANING -

ASSEMBLED MACHINES

Where cleaning is required at the installation and complete disassembly of the machine is unnecessary or not feasible, dry dirt, dust or carbon should first be picked up by a vacuum cleaner to prevent the redistri bution of the contaminant. A small nonconducting nozzle or tube connected to the vacuum cleaner may be required to reach dusty surfaces or to enter into narrow openings. After most of the dust has been removed, a small brush can be affixed to the vacuum nozzle to loosen and allow removal of dirt more firmly attached.

After the initial cleaning with vacuum, compressed air may be used to remove the remaining dust and dirt.

Compressed air used for cleaning should be clean and free of moisture or oil. Air pressure or velocity should be adequately controlled to prevent mechanical damage to the insulation.

Disassembly of the machine and more effective cleaning by a qualified Kato Technician may be required if the above described field service cleaning procedure don't yield effective results.

DISASSEMBLED MACHINES

An initial insulation-resistance reading should be taken on the machine to check electrical integrity. A minimum reading of one to five megohms would be expected with severely contaminated machines. A zero reading may indicate an insulation breakdown requiring repair, not just cleaning.

The high pressure hot water wash method of clean ing, which sprays a high velocity jet of hot water and water containing a mild detergent is normally effec tive in cleaning windings including those subjected to flooding or salt contamination. The detergent spray is followed by multiple sprays with clean water to remove or dilute the detergent. The machine should then be dried until normal insulation resistance values are obtained at room temperature. Solvents are effective for removing oil or grease and may be required if water or detergent is not adequate.

SCHEDULES FOR KATO

MOTOR,GENERATOR,OR

MOTOR-GENERATORS

(SYNCHRONOUS OR

INDUCTION)

Note: Bearing Checks follow this section.

DAILY CHECKS

·1. Check and record operating temperatures on machine bearings.

2. Check and record operating temperatures on machine stator windings.

3. Check and record machine vibration levels.

4. Check control panel voltmeter for proper stability and voltage output.

5. Monitor power factor and machine loading during normal operation.

EVERY 2000 HOURS OR 6 MONTHS OF

OPERATION

1. Remove machine outlet box cover.and visually inspect stator output leads, protective sleeving and insulation for cracking or physical damage.

2. Check all exposed electrical connections for tightness.

3. Check transformers, fuses, capacitors and lightning arrestors for loose mounting or physical damage.

4. Check all lead wires and electrical connections for proper dearance and spacing.

5. Clean inside of outlet box, air screens, bearing hous ings and air baffles with compressed air and electrical solvent.

EVERY 8000 HOURS OR YEARLY

1. Remove machine outlet box cover and visually inspect stator output leads, protective sleeving and insulation for cracking or physical damage. (Same as 2000 hour check)

3. Check all exposed electrical connections for tightness.

4. Check transformers, fuses, capacitors and lightning arrestors for loose mounting or physical damage. ·

5. Check all lead wires and electrical connections for proper clearance and spacing.

6. Check insulation resistance to ground on all machine windings:

A. Main rotating assembly B. Main stator assembly C. Exciter and PMG stationary fields D. Exciter armature assembly

7. Check space heaters for proper operation.

8. Check exciter armature for proper rotating recti fier connection tightness.

EVERY 20,000 HOURS OR 3 YEARS OF

OPERATION

1. Remove machine outlet box cover and visually inspect stator output leads

2. Visually inspect stator output leads, protective sleeving and insulation for cracking or physical damage. (Same as 9000 hour check).·.

3. Check all exposed electrical connections for tightness.

4. Check transformers, fuses, capacitors and light ning arrestors for loose mounting or physical dam age.

5. Check all lead wires and electrical connections for proper clearance and spacing.

6, Check insulation resistance to ground on all machine windings.

A. Main rotating assembly B. Main stator assembly C. Exciter and PMG stationary fields D. Exciter armature assembly

7. Visually inspect machine windings for oil; grease, or dirt contamination. Excessive contami nation may necessitate surface cleaning with com pressed air and electrical solvent.

EVERY 40,000 HOURS OR 5 YEARS

1. Disassemble machine including rotor removal.

2. Check insulation resistance to ground on all machine windings.

A. Main rotating assembly B. Main stator assembly C. Exciter and PMG Stationary fields

o. Exciter armature assembly

3. Clean machine windings using compressed air and electrical solvent or de-greaser and high pressure hot water wash dependent upon severity of contamination.

4. Dry windings to acceptable resistance levels.

NOTE: Refer to the machine Instruction Manuals or con.tact Kato Engineering Parts and Service for additional detail on maintenance procedures and disassembly and reassembly of machines.

BALL AND ROLLER BEARINGS

DAILY CHECKS

1. Visually inspect bearings and seals for excess lubricant.

WEEKLY CHECKS

1. Check and record vibration levels if continous monitoring is available.

EVERY 2000 HOURS OR 6 MONTHS OF OPERA·

TION

1. Check machine vibration and bearing conditon levels with spectrum analyzer or shock pulse. This type of measurement should measure spike energy on the ball or roller bearings.

EVERY 7500 HOURS OR YEARLY

1. Visually inspect bearings, and check seals for excess lubricant.

2. Check machine vibration levels same as 2000/2500 hours of operation. Vibration spectrum and Spike Energy.

EVERY 15,000 HOURS OR 3 YEARS

1. Same as 8000 hours or 1 year of operation.

EVERY 30,000 HOURS OR 5 YEARS

1. Install new factory replacement bearings.

2. Pack bearing with the type and amount of grease specified on the lubrication plate mounted on the machines or consult the machine manual.

3. Monitor unit vibration and spike energy levels after installation.

SLEEVE OIL TYPE BEARINGS

DAILY CHECKS

1. Check oil sight glass for proper levels. Oil should be between 1 /2 and 3/4 level of sight glass.

2. Visually check sleeve bearing housings for signs of oil weepage.

3. Check and record operating temperatures on sleeve oil bearings.

WEEKLY CHECKS

1. Visually inspect bearing seals for oil leaks.

EVERY 2000 HOURS

1. Inspect bearing oil for proper levels and clarity.

EVERY 8000 HOURS OR YEARLY

1. Replace oil with with ISO VG 46 turbine grade mineral oil or equivelant.

EVERY 20000 HOURS OR 3 YEARS OF OPERA

TION

1. Perform sleeve bearing inspection to include removal of upper bearing housing and bearing liner.

Inspect bearing liner, shaft journal and seal surfaces for wear. Reassemble per Kato Engineering proce dure for sealing of sleeve oil bearings.

2. Replace oil with with ISO VG 46 turbine grade mineral oil or equivelant.

EVERY 40000 HOURS OR 5 YEARS.

1. Inspect bearing shaft journals, liners, and oil seals.

2. Replace bearing liners or oil seals. Reseal bearing assembly per Kato sleeve bearing manual.

3. Replace oil with with ISO VG 46 turbine grade mineral oil or equivelant.

IIID E1gl111rl11 P.O. Box 8447 7 Mankato, MN 56002-

Fax(507)345-2798

Publication Number: 350-01003-00 Publication Date: January 1977

INSTRUCTION MANUAL

KATO PILOT EXCITERS

(Permanent Magnet Generators)

Kato Engineering

P.O. BOX 8447

MANKATO, MN 56002-8447

FAX (507) 345•2798

TABLE OF CONTENTS

SECTION PAGE

INTRODUCTION .........................••...........•.....•.........•

II APPLICATION CONSIDERATIONS ......•.................•............•...•

Ill TYPICAL APPLICATIONS •..•••..•......•••....•.••....••.•..•...• PMG as power source for voltage regulator ...•.......••.•.....•••••....•...........• 3 PMG used for field flashing . . • • • . . . . • . . . . . • . . • . . . . . . • . . . . • . . . . . . . . . . • . . . . . • • . • . . 3 PMG as power source for de motor speed control • . • . . . . . . • • . . • . . • . • . . . . . • . . . . . . . . • . . • . 4 PMG as power source for de generator voltage regulator ......•....•.•

IV MAINTENANCE ...•......•........•.•...•.••.••..•......•... , .. , •...... , , . 4 General precautions ....•.....•...•....•...•...................... , , ..••.• , . • 4 General procedure for disassembly and assembly of PMG . . • . . . . . • • . . • • • . . • . • • . . • • . . • • . . . • 5

Permanent Magnet Generator Fie ____ __, Cover for Permanent Magnet Gen. & Exciter P&sy.

Exciter Fie!d

Permanent Magnet Generator Armature

Exciter Armature & --Rotating Rectifier Assy.

-..._ __ Retaining Bolt

Brushless Generator

Figure 1 Typical brushless generator with a permanent magnet generator (Pilot Exciter) used to supply field flashing or voltage regulator power.

350-01003--00

Permanent Magnet Generator ArmatlM'e

Permanent Magnet Generator Field

'------Retaining Bolt

Cover for ~--Permanet

Magnet Generator

Figure 2 Typical KATO static excited ac generator with field flashing. form a permanent magnet generator (Pilot Exciter).

INTRODUCTION

A permanent magnet generator (PMG) is installed as a modif ication in certain Kato generators. It delivers either 120 or 240 volt single phase ac. It functions as a pilot exciter, fur nishing power to the voltage regulator. Its output can be rectified and used for field flashing. It can be also used for any purpose where 120 or 240 volts ac is required and no other source is readily available.

The PMG is basically a revolving field single-phase ac gen erator. Its distinctive feature is the use of permanent magnets instead of electromagnets to provide the magnetic field. As in a conventional ac generator, voltage js induced in the st ationary armature when the magnetic field is rotated inside it.

When installed on a generator, the PMG stator is bolted to the endbell opposite the drive end either by itself (Figure 2) or as part of a larger assembly that includes the exciter field (Fig ure 1 ). The stator consists of armature windings in a laminat ed core which is welded to a steel frame.

The permanet magnets and soft pole tips of the revolving field are permanently attached to a steel hub by non-magnetic tainless steel bolts. The field is magnetized after the rotor is ~sembled and the permanent magnet material has been per .,anently secured in place in the magnetic circuit.

11 APPLICATION CONSIDERATIONS

Several features of the PMG make it valuable as a pilot exciter'.

The first is that it requires no other current source to initiate its own voltage buildup. The advantage of the PMG in this respect is seen when it is compared with a generator using an electromagnetic field. Such a generator must rely on residual magnetism in the field core to initiate voltage buildup when it is started. The field core, not being made of permanet magnet material, retains a comparatively low and variable degree of magnetism from the previous period of operation. This re sidual magnetism may be too low to build up voltage when the generator is started, in which case the field must be flashed, that is, 'given an initial exciting current from an ouside source.

The PMG on the other hand can provide positive voltage build• up • • • it will develop its rated output voltage provided only that it is driven at rated speed. It can therfore be used to pro• vide flashing current for the exciter of the generator to which it is attached.

A second valuable feature of the PMG is that it provides a voltage source that is independent of the terminal voltage of its associated generator. If the PMG is used to power the voltage regulator, full voltage and power will be available for excitation even during heavy transients or short circuit con• ditions.

A third advantage of the PMG is that its terminal voltage is

350-01003-00 designed to power the voltage regulator when driven at rated speed. This makes unnecessary the transformer that would otherwise be required if the generator output did not match the input voltage of the regulator.

A fourth advantage of the PMG results from its allowing the power output stage of the voltage regulator to be isolated from the generator output. Without a PMG, where the voltage regulator takes its power from the generator output, high fre quency interference resulting from switching transients in the voltage regulator output stage could be conducted to the load unless special filtering or isolation was previded.

111 TYPICAL APPLICATIONS

In the following paragraphs, several applications of PMG's are briefly described. This material is presented for the pur pose of discussion only and should not be used for making electrical connections.

PMG AS POWER SOURCE FOR VOLTAGE REGULATOR

Figure 1 shows the general contruction and location of a PMG on a brushless ac generator. The armature of the PMG and the field of the brushless exciter are built into the same frame.

In another design not shown, these two components are sep arate. In yet another design, the exciter field is mounted in board of the bearing and endbell, and the PMG armature only is on the outboard side. In any case, the electrical shematic will resemble Figure 3.

The PMG delivers rated ac voltage to the regulator. The reg• ulator, using power supplied by the PMG, energizes the exciter field. The theory of the generator and voltage regulator is the same as that described in Publication 350-01001-00with the exception that the voltage regulator derives power from the PMG instead of the generator outPut.

During those periods when high current is drawn from the generator, such as during the transients caused by motor start· ing or during short circuit conditions, the generator output voltage will be lowered and the current requirement of the exciter field will be raised. In an istallation where the voltage regulator receives its power from the generator output, this combination of decreased input voltage and increased output requirement may bring about collapse of generator output voltage, unless special series boost provisions are made for these.circumstances.

However, in those installations where the voltage regulator is powered by a PMG, voltage and power for excitation are un affected by the drop in output voltage. Full exciter power is available for motor starting and for short circuit fault clearance.

350-01003-00

Pagel

TO LOAO

VOLTAGE REGULATOR

.. c AC Fl F2

PERMANENT

MAGNET

GENERATOR

Figure 3

GENERATOR

STATOII

PMG supplying power to voltage regulator on brushless ac generator.

SfATIC ,EXCITEM-REGULATOA

'VO\..'TAG!.

AO.Nff 70 LOAD

I

I '------------------... -

RGTATIMG PlnD

Figure 4 PMG used for field flashing on static excited ac generator.

PMG USED FOR FIELD FLASHING

Where positive voJtage buildup is required but separate battery or rectified ac flashing sources are not easily available, a PMG can be used to advantage. It may be installed on either a brushless generator or a static excited generator.

A typical simplified schematic of an installation with a static exciter is shown in Figure 4. The physical location of a PMG on a static excited generator is shown in Figure 2. The rec tified output of the PMG is applied to the field through the normally closed contacts of a relay in the static exciter.

When the generator output voltage builds up to sufficient level, it actuates the relay, transferring the generator field to the static exciter. A separate relay can be wired into the circuit with a static exciter that does not include one.

a:

0 ...

0 ...

a: ..

[c u

,.J w ..J Cl u: 0 Z a: -... ,. 0 z z z ::, Bi :t ., REGULATOR

PM

PERMANENT MAGNET GENERATOR

SENSING VOLTAGE

TACHOMETER

a:

Cl w a:

5l ..

Ill

Figure 5 PMG used to power speed regulator for shunt or compound de motor.

PMG AS POWER SOURCE FOR DC MOTOR SPEED CONTROL

A PMG can be mounted on a de motor to provide ac power for speed control circuitry. A possible application is sketched in Figute 5. In this example, the strength of the flux field, and hence the motor speed, depends on the combined action of the shunt field and control winding. De current in the control winding is varied by the speed regulator. Sensing volt age is obtained from a tachometer; in other designs, a mec hanical governor is used to provide a control signal. The regulator circuitry is powered by ac from the PMG.

PMG AS POWER SOURCE FOR DC GENERATOR

VOLTAGE REGULATOR

A PMG can be mounted on a de generator to provide ac power for the generator voltage regulator circuitry. A possible application is sketched in Figure 6. In this example the volt• age regulator, powered by the PMG, senses the de output of the generator and regulates the generator field current to keep the generator output at rated voltage.

a:

0 ...

ofll I- a:

a: .. .. .,, UC

VOLTAGE REGULATOR

'---v-' PERMANENT l,IAGNET

GENERATOR

SENSING VOLT AGE

TO REGULATOR

0 C GENERATOR

.9 I= u

Figure 6 PMG used as power source for voltage regulator on a de generator.

IV MAINTENANCE

GENERAL PRECAUTIONS

Since there are no bearings, brushes or sliprings and no semi conductor devices, maintenance is minimal. The unit should be kept clean and the vents should be kept open. Keep iron and steel debris away from the rotor.

No attempt should be made to unbolt and separate the parts of the rotor. Breaking the magnetic circuit would alter the permanent magnets, reducing their strength. Reassembling the rotor would not restore the magnetism to its prior state.

Avoid exposing the rotor to excessive heat or mechanical shock. It the rotor is removed and is to remain out of the machine for an extended period, a steel or iron strap or band may be wrapped around the periphery of the rotor to act as a keeper.

If the endbell on the end oppsite the PMG is removed, make sure that the movement of the shaft does not force the PMG rotor against the stator. Note that the air gap in the PMG is considerably smaller than that in a large generator. It may be necessary to remove the PMG rotor when working on the drive end bearing.

WARNING

USE EXTRA CARE WHEN REMOVING ROTOR

TO PREVENT INJURY TO HANDS DUE TO

MAGNETIC ATTRACTION BETWEEN THE

PMG ROTOR ANO THE PMG STATOR OR

GENERATOR SHAFT.

D--- A

GENERAL PROCEDURE FOR DISASSEMBLY AND

ASSEMBLY OF PMG

When disassembling the PMG from the generator or motor, it will be advantageous to remove the rotor first.

To remove the rotor:

1. Take out the retaining bolt and washer. Read

WARNING in general precautions section before removing PMG rotor.

2. Remove the rotor.

3. If the PMG is to remain disassembled for an ex tended period, install a keeper on the rotor. Use a band of iron or steel.

4. In some designs, the exciter armature and rotat• ing rectifier assembly can also be removed at this time.

To remove the stator:

1. Support the stator form an overhead crane or hoist.

350-01003-00 Page5

2. Disconnect the PMG armature leads in the con nection box. Remove any ties holding the leads to the generator frame.

3. If the exciter field is part of the same assembly as the PMG stator, repeat step 2 for the ex citer field.

4. If the rotor has not been taken off first, place thin sheets of insulating material in the air gap betweeen the rotor and stator to keep them from being forcibly attracted to each other and im peding the disassembly.

5. Remove the bolts holding the stator frame to the endbell.

6. Carefully remove the stator frame.

To assemble, reverse steps given in removal procedure.

350-01003-00 Page 6 (blank)

Kato Engineering

P.O. BOX 8447

MANKATO, MN 56002-8447

FAX (507) 345-2798

PUBLICATION NUMBER: 350-01001-00

PUBLICATION DATE: APRIL. 1991

INSTRUCTION MANUAL

BRUSHLESS REVOLVING FIELD

ALTERNATING CURRENT GENERATORS

Serial Number

Includes General Description

Check-out and Operation Maintenance and Troubleshooting

Assembly/Disassembly

1110 En1ine1rin1

P.O. BOX 8447

MANKATO, MN 56002-8447

FAX (507) 345-2798

WARNING

ONLY QUALIFIED PERSONNEL FAMILIAR WITH THE CONSTRUCTION AND OPERA

TION OF THIS EQUIPMENT AND THE HAZARDS INVOLVED SHOULD INSTALL,

ADJUST, OPERATE AND/OR SERVICE THIS UNIT. READ AND UNDERSTAND THIS

MANUAL IN ITS ENTIRETY BEFORE PROCEEDING. FAILURE TO OBSERVE THIS

PRECAUTION COULD RESULT IN SEVERE BODILY INJURY OR LOSS OF LIFE.

DANGER

The user is responsible for conforming to the National Electric Code and all other applicable local codes, wiring, grounding, disconnects, and overcurrent protection are particularly important. Failure to observe this precaution could result in severe bodily injury or loss of life.

DANGER

Subsequent steps require rotating parts and/or electrical circuits to be exposed.

Stay clear if unit must be running or disconnect and lockout or tag power source if contact must be made. Failure to observe these precautions could result In severe bodily injury or loss of life.

CUSTOMER BOY~E MACH.

GENE2ATOR TYPE NO

QUANTITY KATO PART NO

i)f}4-l.:l)(r28-0!)

•l

G

I) 1} :::.- 6 0 (•28- :) i)

0 (1::,-6 0 043- 0 0

OOS-6-0G6S-00

009-00056-!U 017-34~50-::'.6

031-; SJC:Q3-C.O

034-G O 04S- i 2 i). :! i,S - !~ • ij O i) - 1 :~ 037-~iJ(itj•j-f2

130-21002-23

1)4G-2i331-1&

1 !)\ r 8 CUSTGMER ?Q E1J7-1 lQ-SSA

OESCRIFT::CN

ENDBELL (1039-0~}

ADP.PT,JR t JS4

DRIFFROCF SHIELD

B,lltNu

USE 009-00059-17 COVER

FAf'J ,~e~sY

STL BAFFLE 25ID X 3

COUPLIN~ HUB (1218-01)

USE 036-60003-12

OLlTLET BOX COVER

OUTLE! BO~ COVER

DRIVE PLATE ASSY

WOUND STATOR ASSY

tXC FLO ASS~ WOUND

RC-TA.TING AS.SY

EXC A2M ASSY WOUND

~QTAriNG ~ECTIFIER AS2Y

DIODE~ ST,e.,r-lDfl .. RD D- I G!JE ;I Ft:S\tER .s~:

~OJ - SURGE SUPF~E330~

TABLE OF CONTENTS

SECTION 1 INTRODUCTION AND DESCRIPTION PAGE

1. 1 Introduction ................................................................................................................................................. 1.

1.2 General Description .................................................................................................................................... 1.

1.3 Construction ............................................................................................................................................... 1.

SECTION2 INSTALLATION

2.1 .Receiving Inspection .................................................................................................................................. 5.

2.2 Unpacking and Storage .............................................................................................................................. 5.

2.3 Location ...................................................................................................................................................... 5.

2.4 Assembly to Prime Mover ........................................................................................................................... 6.

2.5 Belt Drives - General Information ............................................................................................................. 14.

2.6 V-Belt ........................................................................................................................................................ 14.

2. 7 Flat Belt .................................................................................................................................................... 14.

2.8 Gear Belts (Timing Belts) ......................................................................................................................... 14.

2.9 Gear and Flexible Couplings - GeneraJ lnfomiation ................................................................................. 14.

2.1 O Gear Drive ................................................................................................................................................ 14.

2.11 Installation and Alignment of Flexible Coupled Drives ............................................................................. 14.

2.12 Flywheel and Twin Disc Clutch or Other Flexible CoupHng ...................................................................... 15.

2.13 Vibration .................................................................................................................................................. 15.

2.14 Doweling .................................................................................................................................................. 15.

2.15 Electrical Measurements and Connections .............................................................................................. 16.

2, 16 Protective Devices .................................................................................................................................... 17.

SECTION 3 OPERATION

3.1 Idling ......................................................................................................................................................... 18.

3.2 Initial Start-up with both Auto Manual and Automatic Voltage Control.. ................................................... 18.

3.3 Initial Start-up Procedures for generators with Automatic Voltage Control .............................................. 18.

3.4 Field Flashing ........................................................................................................................................... 19.

3.5 Parallel Operation .................................................................................................................................... 19.

3.6 Continuous Operation ............................................................................................................................... 20.

SECTION4 MAINTENANCE

4.1 Preventive Maintenance ........................................................................................................................... 21.

4.2 Cleaning .................................................................................................................................................. 21.

4.3 Windings - Protection ............................................................................................................................... 21.

4.4 Insulation Resistance Test ....................................................................................................................... 21.

4.5 Bearing Lubrication ................................................................................................................................... 22.

4.6 Testing Brushless Exciter Rotating Rectifiers with an Ohmmeter ............................................................ 22.

4. 7 Testing Brushless Exciter Rotating Rectifiers with a Test Lamp .............................................................. 22.

4.8 Testing Surge Protedor with Test Lamp .................................................................................................. 23.

4.9 Restoring Residual Magnetism ................................................................................................................. 24.

SECTION 5 TROUBLESHOOTING ................................................................................................ 25.

TABLE OF CONTENTS (CONTINUED)

SECTIONS ASSEMBLY AND DISASSEMBLY PAGE

6.1 Bearing Rell'IC)val ........................................................................................................................................ 29.

6.2 Bearing Installation ................................................................................................................................... 29.

6.3 Exciter Armature and Rotating Rectifier Assembly Removal ................................................................... 29.

6.4 Exciter Armature and Rotating Rectifier Asseni>ly Installation ................................................................ 29.

6.5 Ren10vlng and Replacing Exciter Stator Assembly .................................................................................. 30.

6.6 Assembly and Disassembly of Single Bearing Engine Drive Generators ................................................. 31.

6.7 Assembly and Disassembly of Two Bearing Generators ......................................................................... 31.

6.8 Assembly and Disassembly of Synchronous Brushless Dual Generators

Fan Mounted at Drive End ........................................................................................................................ 34.

6.9 Assembly and Disassembly of Synchronous Brushless Dual Generators with Center Mounted Fan ......................................................................................................................... 34.

SECTION7 RENEWAL PARTS ORDERING INFORMATION ...................................... as.

ii

LIST OF ILLUSTRATIONS AND TABLES

SECTION 1 INTRODUCTION AND DESCRIPTION PAGE

Figure 1-1 Figure 1-2 Figure 1-3 Figure 1-4 Figure 1-5 Figure 1-6 Figure 1-7 Figure 1-8

Stator of Kato Revolving Field Synchronous Alternating Current Generator .............................................. 1.

Lead Terminals Located in Outlet Box ....................................................................................................... 2.

Generator Rotor with Exciter Armature and Rotating Rectifier Assembly lnstalled .................................... 2.

Exciter Armature and Rotating Rectifier Assernbly ..................................................................................... 2.

Exciter Stator and Windings ....................................................................................................................... 3.

Typical. ·shielded" Bearing and Bearing Housing Construction .................................................................. 3.

Typical 11Regreasable" Bearing and Bearing Housing Construction ........................................................... 3.

Block Diagram, Typical Brushless Generator - Voltage Regulator System ................................................ 4.

SECTION 2 INSTALLATION

Figure 2-1 Figure 2-2

Table 2-1 Figure 2-3 Figure 2-4 Figure 2-5 Figure 2-6 rable 2-2 Figure 2-7 Figure 2-8 Figure 2-9

Figure 2-i0

Figure 2-11 Figure 2-12 Figure 2-13

Typical Single Bearing Generator - Engine Coupling .................................................................................. 6.

Extension of Generator Rotor Shaft for Mounting of Exciter Rotor Assembly ............................................ 6.

(Outboard Exciter Generators) Allowable Flywheel and Drive Disc Recess Run-out .................................................................................. 7.

Checking Flywheel Run-out ........................................................................................................................ 7.

Checking Engine Flywheel Housing Run-out ............................................................................................. 7.

Single Bearing Generator Drive Plate and Adaptor .................................................................................... 8.

SAE Flywheel ............................................................................................................................................. a.

Recommended Torque SAE 5 Steel and SAE a Steel Cap Screws .......................................................... 9.

Typicat Drive Disc to Flywheel Installation ................................................................................................. 9.

Checking Generator Shaft Run-out ............................................................................................................ 9.

Procedures tor Removing and Installing an Outboard Brushless Exciter Armature Assembly .................................................................................................................................. 11.

Procedures for Removing and installing an Outboard Brushiess Exciter Armature Assembly and PMG Rotor ........................................................................................................ 12.

Testing Coupling Alignment. ..................................................................................................................... 13.

Checking Alignment of Twin Disc Coupling .............................................................................................. 15.

Chart for Converting Megger Readings to 40 Degrees C ......................................................................... 17.

SECTION 3 OPERATION

Figure 3-1 Synchronizing Paralleled Generators with Test Lamps ............................................................................ 19.

Figure 3-2 Guide to Allowable Phase Unbalance ...................................................................................................... 20.

SECTION4 MAINTENANCE

Table 4-1 Figure 4-1 Figure 4-2 Figure 4-3 Figure 4-4

Preventive Maintenance Chart ................................................................................................................. 21.

Testing Rotating Rectifiers with an Ohmmeter ......................................................................................... 22.

Test Lamp ................................................................................................................................................. 22.

Full Wave Rotating Rectifier and Exciter Armature Assembly .................................................................. 23.

Dual E=xciter Rotating Rectifier and Exciter Armature Assembly .............................................................. 23.

1ECTION 5 TROUBLESHOOTING

~able 5-1 Troubleshooting Chart .............................................................................................................................. 25.

iii

LIST OF ILLUSTRATIONS AND TABLES (CONTINUED)

SECTION& ASSEMBLY AND DISASSEMBLY PAGE

Figure 6-1 Figure 6-2 Figure 6-3

Figure 6-4

F19ure6-5a

Figure 6-Sb

Figure 6-6a

Figure 6-6b

Figure 6-7

Figure 6-8

Removing Bearing from Generator Shaft ................................................................................................. 29.

Installing Bearing on Generator Shaft ...................................................................................................... 29.

Removing Exciter Armature and Rotating Rectifier Assembly ................................................................. 30.

Installing Exciter Armature and Rotating Rectifier Assembly ................................................................... 30.

Typical Kato Single Bearing Revolving Field Brushless Generator with Outboard Exciter and Exciter Frame ........................................................................................................ 32.

Typical Kato Single Bearing Revolving Reid Brushless Generator with OUtboard Exciter Field Mounted on Encl>ell ............................................................................................. 33.

Typical Kato Two Bearing Revolving Field Brushless Generator with Outboard Exciter and Exciter Frame ........................................................................................................................ 32.

Typical Kato Two Bearing Revolving Field Generator with Outboard Exciter Field Mounted on Endbell ......................................................................................................................... 33.

Kato Synchronous Brushless Revolving Field Dual Generator or Motor-Generator with Fan Mounted at Drive End ................................................................................................................ 35.

Kato Synchronous Brush(ess Revolving Field Dual Generator or Motor-Generator with Center Mounted Fan ......................................................................................................................... 35.

iv

SECTION 1

INTRODUCTION AND DESCRIPTION

1.1 INTRODUCTION

This manual contains instructions for installing, operating and maintaining Kato Brushless Revolving Field Genera tors.

Electrical connection drawings, dimensional drawings and part listings for the specific model, type and serial number of generator are usually contained as supplementary information in a separate excerpt of the generator manu

al. These drawings are the official source of information for making electrical coMections or ordering replacement parts.

1.2 GENERAL DESCRIPTION

1.2.1 The Synchronous Alternating Current Genera-

tors described in this manual are of the brushless revolv ing field ty.pe of single and two bearing construction.

Single bearing generators are designed for direct coupling to a stationary prime mover and two bearing generators· are designed for gear, belt or flexible coupling to a stationary prime mover. The generators are manufactured in many sizes and ratings with various optional features such as enclosures, terminal boxes, bearing types, and· controls. Generator excitation current is supplied from a direct connected brushtess rotating DC exciter.

1.2.2 The generators may be supplied with various

controls designed to provide the user's exact power needs. Controls may be contained in separate wall mounted cubicles, In free standing control aibicles, or in a control box mounted to the generator frame depending upon the number and size of the controls required or the customer's specifications.

1.2.3 Generators may be supplied with permanent

magnet generators (PMG) to provide power to the regulator under short circuit conditions, or field flashing (In case generator or brushless exciter loses residual magne tism) and to reduce electromagnetic interference.

1.2.4 . Generators are supplied with a side mounted terminal box which is designed to accommodate the conneciions to the load. Specially built oversized box can also accommodate various controls and protection devices such as the voltage regulator, surge suppressors, md current transformers. Auxiliary boxes are provided to .1c:commodate accessory connections to RTD's, space heaters, bearing vibration sensors, exciter and PMG leads.

1.3 CONSTRUCTION

The basic generator includes frame and stator, rotor, enclosures and brushless exciters with optional perma nent magnet generator mounted on the shaft to provide power to the voltage regulator.

1.3.1 The generator frame is fabricated of heavy steel

members welded to the endbell or bearing bracket pilot rings. The feet are welded to the frame to simplify installation and alignment with the primer mover. Eye bolts are fastened to the frame to enable lifting of the generator with an overhead hoist. Steel wrapper cover encloses the frame assembly.

1.3.2 The generator stator core is built of laminated

electrical grade steel. Laminations are secured under pressure and clamped to steel endrings. Wi{ldings are inserted into the stator slots and the entire assembly is vacuum pressure impregnated with 100…