QUALITY DOSSIER Tuabin Máy Phát nhà máy thủy điện

MAINTENANCE MANUAL AND QUALITY DOSSIER SERIAL NUMBER 61016878 PROJECT JVPR01127 DATE June 2021 GENERATOR PO 1250 O4D8 DAK DI 1 INDEX 1 0 DATA SHEET 2 0 MAINTENANCE MANUAL 3 0 CONFORMITY CERTIFICATE 4.

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INDEX

1.0 DATA SHEET 2.0 MAINTENANCE MANUAL 3.0 CONFORMITY CERTIFICATE 4.0 FINAL TEST

5.0 IPP 6.0 MATERIAL CERTIFICATES 6.1 FRAME

6.2 SHAFT 6.3 MAGNETIC SHEET 6.4 COPPER

6.5 SHIELDS 6.6 FAN 6.7 EXCITER 6.8 POLAR EXPANSION 6.9 BEARINGS

6.10 AUXILIARY ELEMENTS 7.0 DRAWINGS

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1.0 DATA SHEET

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Confidentiality: 3 / CUSTOMER INFORMATION FINAL USER DOCUMENTATION

Approval process: Electronic: PDM Flow Documentation Type: Title:

Design

DATASHEET PO 1250-O4D8 DAK DI 1

Prepared: CECASTILLO

The present document, its content, its annexes and/or amendments (the “Document”) has been drawn up by GAMESA CORPORACIÓN TECNOLÓGICA, S.A (“Gamesa”) for information purposes only and contains private and confidential information regarding Gamesa and its subsidiaries (the “Company”), directed exclusively to its addressee Therefore, it must not be disclosed, published or distributed, partially or totally, without the prior written consent of Gamesa, and in any case expressly indicating the fact that Gamesa is the owner of all the intellectual property All the content of the Document, whether it is texts, images, brands, trademarks, combination of colours or any other element, its structure and design, the selection and way of presenting the information, are protected by intellectual and industrial property rights owned by Gamesa, that the addressee of the Document must respect In particular (notwithstanding the general confidentiality obligation), the addressee shall not reproduce (except for private use), copy, transform, distribute or publish to any other third party, any of the information, totally or partially.

ICA-TEC-001-R06 (en) Edition 1

INDEX

1 TECHNICAL DATASHEET 2

2 EFFICIENCY TABLE 3

3 REACTANCES 3

4 TIME CONSTANTS 3

5 CHARACTERISTICS CURVES 4

6 V CURVES 5

7 POWER CHART 6

8 EFFICIENCY CURVES 7

RECORD OF CHANGES

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Confidentiality: 3 / CUSTOMER INFORMATION

1 TECHNICAL DATASHEET

GENERAL

Efficiency at rated power, frequency and voltage at 100% load See point 2

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2 EFFICIENCY TABLE

• Efficiency calculated for copper at 95ºC (as per client specification)

• Additional losses included as calculated

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5 CHARACTERISTICS CURVES

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6 V CURVES

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7 POWER CHART

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8 EFFICIENCY CURVES

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2.0 MAINTENANCE MANUAL

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Confidentiality: 3 / CUSTOMER INFORMATION OPERATION AND MAINTENANCE

Documentation Type: Title:

Product INSTALLATION, OPERATION AND

MAINTENANCE USER MANUAL DAK DI

INSTALLATION, OPERATION AND MAINTENANCE USER MANUAL DAK DI 1

PW1250-O4D8

PROJECT Nº: JVP/ R01127

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Gamesa Electric recommends that before operating the generator read this manual and make sure all personnel who work in scope of installation, operation and maintenance have access to this manual The whole manual shall

be read to have a full survey of technical characteristics of the machine and of the precautions to be taken in order to obtain a safe and reliable operation

Owing to the great variety of operating conditions, the operating and maintenance manual can only cover general usage situations, which were agreed between Gamesa Electric and end customer, for reasons of clarity and understanding This manual contains:

• General information and safety rules

• Specific technical information of the machine components

• Maintenance and inspection instructions

• Assembly and disassembly instructions

In case of further doubt, please contact Gamesa Electric representatives

Gamesa Electric S.A.U

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PO1250-O4D8 INDEX

SECTION 1: GENERAL INFORMATION AND SAFETY INSTRUCTION 6

1 MACHINE IDENTIFICATION AND CHARACTERISTICS 7

2 SAFETY DIRECTIVES 8

2.1 SAFETY INSTRUCTIONS 8

2.2 SAFETY WORKS: 9

3 QUALITY CONTROL STATEMENT 10

4 TRANSPORT 10

5 HANDLING 10

6 RECIVING INSPECTION 11

7 SCOPE OF MOUNTING 11

7.1 ASSEMBLING SITE 11

7.2 SHORT-TERM STORAGE 12

7.3 LONG-TERM STORAGE 13

7.4 TECHNICAL INSPECTION 14

7.5 BALANCING 14

7.6 SHAFT-END COUPLING 14

7.7 INSTALLATION 15

7.8 PROTECTION 15

7.9 EARTHING SYSTEM 15

7.10 MACHINE ALIGNMENT 16

SECTION 2: DESCRIPTION OF THE MACHINE COMPONENTS 17

8 MAIN COMPONENTS 18

8.1 GENERAL CONSTRUCTION 18

8.2 STATOR 18

8.2.1 Stator housing 18

8.2.2 Stator Core 18

8.2.3 Stator winding 19

8.2.4 Insulation Class 20

8.3 ROTOR 20

8.3.1 Shaft 20

8.3.2 Field Windings 20

8.3.3 Excitation system 20

8.3.4 AVR 21

8.3.5 Ventilator 21

8.4 COMPLETE UPPER SHIELD N.D.E 21

8.4.1 Upper shield 21

8.4.2 Insulated sleeve bearing N.D.E 21

8.5 COMPLETE LOWER SHIELD D.E 22

8.5.1 Lower shield 22

8.5.2 Sleeve bearing D.E 22

8.6 COOLING SYSTEM 22

8.7 LUBRICATION / REFRIGERATION BEARING SYSTEM 22

8.7.1 Lubrication / cooling upper thrust bearing 22

8.7.2 Lubrication / cooling lower guide bearing 23

8.8 BRAKE SYSTEM 23

8.9 OIL INJECTION SYSTEM FOR N.D.E BEARING 24

8.10 TERMINAL BOX 25

8.11 CONDITION MONITORING OF THE GENERATOR 25

8.11.1 Stator winding sensors 25

8.11.2 Bearing sensors 25

8.11.3 Hydrostatic control devices 26

8.11.4 Space heaters 26

8.11.5 Speed sensors 26

8.11.6 Vibration sensors 26

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PO1250-O4D8

8.11.7 Brake sensors 26

8.11.8 Earth shaft brush 26

8.11.9 Measurement and protection 27

8.11.10 Excitation 27

SECTION 3: GENERAL INFORMATION AND SAFETY INSTRUCTION 28

9 INSTALLATION - ALIGNMENT 29

9.1 ERECTION SEQUENCE 29

9.2 STATOR FOUNDATIONS 30

9.3 CHECK OF FOUNDATION 32

9.4 DISASSEMBLY OF THE TRANSPORT LOCKING DEVICE 33

9.5 THERMAL ELONGATION CORRECTION 35

9.6 AXIAL ALIGNMENT 35

9.7 INSTRUCTIONS FOR COUPLE ALIGNMENT 35

9.7.1 Alignment 36

9.8 INSTRUCCIONES FOR CHECKING ALIGNMENT 36

9.8.1 Vertical machines 36

9.8.2 Horizontal and vertical machines 36

9.8.3 Radial misalignment 36

10 COMMISSIONING 39

10.1 PREPARATION FOR COMMISSIONING 39

10.1.1 Electrical connections 39

10.1.2 Direction of rotation 39

10.1.3 Ground connections 39

10.1.4 Slip rings, brushes (only in case of static excitation) 39

10.1.5 Insulation resistance 39

10.1.6 Protection devices 41

10.1.7 Bearing insulation 41

10.1.8 Space heaters 41

10.2 CALIBRATION OF CONDITION MONITORING DEVICES 41

10.2.1 Temperature measurement 41

10.3 COMMISSIONING INSPECTION 44

10.3.1 Electrical connection check 44

10.3.2 Lubrication check 44

10.4 FIRST START UP SUPERVISION 44

11 OUT OF SERVICE CHECKLIST 45

SECTION 4: MAINTENANCE, INSPECTION AND DISASSEMBLY 47

12 MAINTENANCE & INSPECTION 48

12.1 PREVENTIVE MAINTENANCE 48

12.2 GENERAL INSPECTION 49

12.3 MAINTENANCE SCHEDULE 52

12.3.1 General 52

12.3.2 Cleaning 52

12.3.3 Sleeve bearings maintenance: 56

12.3.4 Sleeve bearing lubrication oil control 59

12.3.5 Winding maintenance 62

13 FAULT DIAGNOSIS CHART 65

14 DISASSEMBLY OF MACHINE 67

14.1 SLEEVE BEARING DISASSEMBLY (N.D.E.) 67

14.2 SLEEVE BEARING DISASSEMBLY (D.E.) 67

14.3 ROTOR DISMOUNTING AND EXTRACTION 67

14.4 REPLACEMENT OF THE MACHINE PARTS 68

14.4.1 Replacement damaged diodes 68

14.4.2 Replacement of the brushes 68

15 WARRANTY TERMS 69

APPENDIX 1 – PW 1120_O4D8 – DATASHEET GD473499 70

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PO1250-O4D8

APPENDIX 2 - CHECKLIST IN THE EVENT OF EQUIPMENT STORAGE 71

APPENDIX 3 – GENERATOR SPECIFIC DRAWINGS AND DOCUMENTS 72

APPENDIX 4 - CHECKLIST FOR COMMISSIONING 73

APPENDIX 5 – SLEEVE BEARINGS INSTRUCTIONS FOR MOUNTING AND DISMOUNTING 74

APPENDIX 6 - LIST OF AUXILIARIES GD473602 75

APPENDIX 7 – AVR DECS 250 WITH MOUNTING PLATE 76

LIST OF TABLES Table 1 Storage protection grade categorization 14

Table 2 Radial misalignment 37

Table 3 Radial misalignment (horizontal) 37

Table 4 Axial misalignment 37

Table 5 Types of inspections 49

Table 6 Commercial comparable and permissible products and suppliers 54

Table 7 Types of lubricants 61

Table 8 Winding maintenance 63

Table 9 Maintenance Plan 64

Table 10 Abnormal service disturbances-causes and instructions 65

LIST OF FIGURES Figure 1 Name plate of PO 1250-O4D8 7

Figure 2 PO 1250-O4D8 generator mounting drawing 19

Figure 3 Machined shaft with polar mounting wheel 20

Figure 4 The Excitation system scheme in brushless exciter 21

Figure 5 Rotor locking device 33

Figure 6 Shaft radial vertical misalignment checking 37

Figure 7 Shaft radial horizontal misalignment checking 37

Figure 8 Shaft openings checking 38

Figure 9 Diode details 68

List of abbreviations used

D.C / d.c Direct current

RECORD OF CHANGES

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PO1250-O4D8

1 MACHINE IDENTIFICATION AND CHARACTERISTICS

This manual applies to 3-phase Synchronous generator with Salient pole rotor PO1250- O4D8 designed and manufactured by Gamesa Electric, for potential use in hydropower generation

The machine nameplate in figure 1 represents the entire characteristic parameters and values required for the machine identification and the operation of the motor The nameplate is fixed on the machine frame The content of the nameplate is in accordance with the data list required by the IEC 60034-1 Standard The machines manufactured in the European market have markings with:

• The CE mark ie European declaration of incorporation according to machinery directive

• Generator rating and identification data are outfitted on labels and nameplate Packing nameplates provide a permanent record of generator attributes, manufacturing plant identification contact details Data and information regarding the electrical characteristics of the machine can be obtained from the name plate

Figure 1 Name plate of PO 1250-O4D8

The generator has been designed, according to the customer requirements, to work within the following ambient conditions:

• Ambient temperature within the limits specified by the IEC Standard

• Max operating altitude 500 meters over the sea level

• Mounting arrangements: Vertical mounting Code IM 4015 according EN 60034-7

• Cooling system: According to IC 21

• Protection class: According to IP 23

The bearings used in this machine are as following:

• Non-Drive End (N.D.E.) Insulated Bearing MICHELL AV14SNT3

• Drive End (D.E.) Bearing MICHELL 13GT1

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PO1250-O4D8

For more information, the data sheet of the machine has been included in this manual as Appendix 1

NOTE: The information given on the bearing plate must imperatively be followed Failure to do

so will void the warranty for the bearings

2 SAFETY DIRECTIVES

2.1 SAFETY INSTRUCTIONS

To avoid possible accidents, safety measures and devices required at the installation site must

be in accordance with the instructions contained into this manual and the regulations stipulated for the safety at work In particular the apparatuses and the equipment related to this manual are designed for utilization in hydro power stations where there is presence of high voltage and current When equipment is installed, the end user is responsible for adopting country specific safety rules and required protective measures

The Safety Responsible in charge during the erection, commissioning and operation of this equipment, must assure that the utilized personnel are qualified1 for the job The personnel have taken good note of the operative instructions and of the specific documentation related

to the equipment on which he is working, and that these instructions are available on the job site Any intervention on the equipment covered by this Manual done by non-qualified personnel is strictly forbidden

Workplace equipment handling safety depends on the attentiveness, care, and common sense of the personnel who install, operate, and maintain the machine In addition to the safety measures cited, as a matter of principle, the use of caution is necessary when you are near the machine Always pay attention to your safety during manual handling, the term manual handling covers a wide variety of activities including lifting, lowering, pushing, pulling and carrying If any of these tasks are not carried out appropriately there is a risk of injury While in operation, this equipment has energized or exposed rotating parts that can present high voltages or high temperatures Therefore, the Only qualified personnel are supposed to carry out transportation, storage, assembly, installation, start-up, maintenance and repair services on operation with open terminal boxes, non-protected couplings or wrong handling without considering the following guidelines in order may cause serious injury to people and result in material damage:

1 The system shall be disconnected Make sure to disconnect the auxiliary circuits as well

2 Any reconnections shall be prevented

3 Make sure that the equipment shall be at zero voltage

4 Ground and short-circuit

5 ll live components that present in the in close proximity components shall be covered or isolated

Note: To energize the system, the guidelines shall be applied in reverse order to prevent any serious injury to

people and material damage

All personal carrying out operation, maintenance or working in or with a power station or a Gamesa Electric’s generator set must wear appropriate Personal Protective Equipment (PPE) Recommended PPE includes: Head protection, safety footwear hand protection and High visibility vest

1 Qualified personal definition shall comply with the Standard IEC 60364-6-61

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The use of a lightning bolt within an arrowhead symbol, enclosed in a yellow triangle warns

of machines contain live parts, that can cause fatal or severe injuries and substantial

material damage can occur if the covers are removed or if the machine is not handled, operated, or maintained properly

• Always observe the basic safety rules when carrying out any work on the machine

• The covers shall be removed only using the guidelines described in this manual

• The machines shall be Operated and maintained properly

Rotating parts

The symbol indicates that electric machines contain unsafe rotating parts that can cause

fatal or severe injuries to a person and substantial material damage can occur if the covers are removed or if the machine is not handled, operated, or maintained properly

• The machines hall be operated and maintained properly

• Secure free-standing shaft ends

Perform regular maintenance on the machine

Hot surface The symbol indicates that electric machines possess hot surface that can cause fatal or

severe injuries and substantial material damage can occur if the covers are removed or if the machine is not handled, operated, or maintained properly

• Allow the machine to cool before starting work on the machine

• The machines hall be operated and maintained properly

Hazardous chemical substances

The symbol indicates that hazardous chemical substances required for the setup,

operation and maintenance of machines can present a health risk that can cause poisoning,

skin damage, cauterization of the respiratory tract, and other health damage to the person

• Read the information in the operating instructions and the product information

• Observe the relevant safety regulations and wear the personal protective equipment

specified

Flammable chemical substances

The symbol indicates that flammable chemical substances required for the setup,

operation and maintenance of machines may be flammable, that burns and other damage to

health and material may result

• Read the information in the operating instructions and the product information

• Observe the relevant safety regulations and wear the personal protective equipment

specified

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PO1250-O4D8

3 QUALITY CONTROL STATEMENT

Over the years Gamesa Electric demonstrates to provide a consistent high quality of work in accordance with the requirements and expectations of our customers At Gamesa Electric, quality assurance process and standard operating procedures apply to all aspects of our work, specifically including: distribution of technical information, preliminary inspection, reception of raw materials or a component, all aspects of the manufacturing process, final inspection, testing and dispatching of the machine

Gamesa Electric values a culture of continuous improvement Any quality issues, whether internal or external, are indicative of an opportunity for improvement The process for corrective actions between Gamesa Electric design team and facility personnel ensures that any issues are systematically evaluated, and the relevant processes are reviewed

Note: For additional information on these tests, please check the IEC-60034 Standard

NOTE: Non-agreement with such instructions will void the product warranty

The generator package should never be dropped Handle it carefully (without sudden impacts) to avoid bearing damage

• Machine must be handled with the rotor locked

• This generator is fitted with eyebolts and a suspension beam for lifting purposes

• Pay attention to the weight of the machine (47 Tn)

• Slings must never be in contact with windings (or other parts susceptible to be damage)

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If equipment received in damaged or incomplete condition the communication either to the Insurance Company or to Gamesa Electric should be accompanied with surveyor's report and the photographs or other useful evidence

the cranes (total generator weight = 47 Tn)

• Prepare documentation for the installation

• After box receiving inspection

• After part receiving inspection control

In the event of any damage or loss in transit the carriers and manufacturer should be

advised in writing within the 3 working days Gamesa Electric doesn’t register any

complain about the reception after this period

During the generator assembly, maximum caution should be taken to prevent any alien body, such as tools, screws, steel shavings, etc., from entering or falling inside the machine

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temperature range is from 10ºC to 50ºC (from 50 to 122ºF) with a maximum relative humidity

of 75% In case higher relative humidity values are reached, space heaters must be turned on in order to keep the machine 5 ºC above the dew point to avoid condensing

• The floor under the machine must be free from excessive vibrations, maximum allowable vibration speed is Veff <0.2 mm/s If there are presence of vibrations or if they may be observed later, the machine must be kept isolated by means of elastic blocks under the feet

• Anticorrosive painting under antifriction surfaces must be inspected periodically as well Any corrosion on the antifriction surfaces must be removed using abrasive paper As well make sure that anticorrosive agent is not cracked on machined surfaces

• When the machine is stored in a wooden box, little orifices must be forecasted for ventilation

• During the storage, rotor shall be locked

• No chemicals, acids, alkalis or storage batteries shall be stored in the same location with machine The insulation resistance of the stator and rotor must be checked The thermo-resistance sensors (PT-100) shall be checked

• Rolling bearings must be well lubricated during storage with the acceptable grease type found on the bearing plate on the machine The bearings and all its parts must be inspected after the storage and before the commissioning if the machine The rotor shall be turned for 10 revolutions every three months to keep the bearings in good condition

• Remove any possible transport locking device during turning the rotor Machine may be provided with a locking device to protect the bearings against damage during transport and storage Check the bearing locking device periodically

Perform these inspections each 3 months:

• Perform the Insulation resistance test for stator and rotor

• Check the winding temperature (PT 100)

• Ensure that surfaces are free from rust If rust is observed, essential measures must be taken in order to protect the machine

• Check that anticorrosion agent is not cracked on machined surfaces

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1 In any event, it is advisable to store the machine under a cover and not outdoor In the event of outdoor storage, electrical storms may lead to the total or partial destruction of the machine; it may lead to discharge of the machine

2 Apply preventive measures to keep the machine unexposed from severe conditions of humidity and condensation so that the metallic parts do not rust, thereby keeping the machine covered with water-proof traps

3 Protect the machine from potential causes of damage such as floods, fire, suspended elements, detritus from birds etc

4 Do not store the machine at any time in places subject to vibrations, due to the risk that this implies for the bearings

5 Dust and dirt must be prevented from penetrating the machine; therefore, all orifices must be covered

6 Cover any entry that facilitates access to rodents, which can damage the machine’s insulation

7 In case of static excitation, lift the brushes of the slip rings so that there is no contact between both these parts of the machine

8 The machine should be maintained in an environment that is not cold, and the heating elements should

be connected in order to warm the air that passes by the brushes, the brush holders or the windings

9 The winding insulations, both on the stator and on the rotor, shall be inspected quarterly to ensure that insulation resistance is within the range of acceptable values It is advisable to take measurements using a Megger tester

ATTENTION: The instructions from point 1 to 9 shall be acted upon quarterly In case of storage event, it’s recommended to utilize the storage checklist presented in APPENDIX 2

For the protection of machines with slide bearings and shafts in place, we recommend the following measures:

• User must seal the bearing seal tapped holes with plugs, connecting flanges with blank flanges and the gap between the seal and shaft or between shaft and housing respectively with self-adhesive tape

• User shall remove the plexiglass cover or top sight glass and spray corrosion inhibitor, which needs not to be removed (e.g Tectyl 511 M or Valvoline) through the opening in the housing using a compressed air spray gun

• Airless injectors are not suitable since they do not ensure adequate atomisation of the corrosion inhibitor

• Fit a bag with desiccant (e.g silica gel) below the plexiglass cover or the sight glass in order to prevent condensation

• Seal the bearing again

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Table 1 Storage protection grade categorization

The corrosion inhibitors used are the following:

Though Tectyl 511 M is compatible with lubricants, it is recommended, however, to remove it prior to installation Dirt particles may settle in the protective film, even if the utmost care is taken during packing and transportation which would possibly affect the operational safety

In case of grades of protection 2 and 3 Tectyl 511 M is applied to the spherical seating in the housing All other surfaces susceptible to corrosion are protected with Tectyl 846 or Tectyl 164

7.4 TECHNICAL INSPECTION

Prior to dispatching, all machines are factory tested, balanced and supplied in proper conditions It is recommended to perform required tests as per the specified procedure and quality control while receiving the machine, in order to detect damages during transport service on time In case of damages, the transport company must be notified

7.5 BALANCING

If the shaft extension has a key-way, balancing has been performed with half key-way The torque transmission elements, gear-wheels, half-couplings etc must be balanced on an auxiliary shaft and with half key-way

7.6 SHAFT-END COUPLING

Shaft end shape (cylindrical and conical with key-way or stepped cylindrical for mounting a coupling plate with interference) is shown in the dimensional drawing

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1 Remove all accessories dedicated to transport

2 Locate generator in vertical position

3 Disassembly rotor blocking device (please check section 9.3)

4 Remove antioxidant product from all mechanized surfaces and clean them

5 Locate generator in its final position

6 Assemble hydrostatic unit (if supplied)

7 During installation it is required to check rotor pitch

Check pitch before continue with installation

8 Ensure correct leveling of the whole generator Since these bearings are a compact design none adjustment is required for the pads Rotor correct position will be ensured due to good levelling

9 Fill with oil the bearing vat

10 Adjust earth brush (If supplied)

11 Check upper bearing insulation before and after installation and note it

12 Generator is prepared to start commissioning activities

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to section 9

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Note: To know the external dimension details & performance parameters of any specific machine, the user

needs to refer to general dimensions & mounting drawings and technical data sheets put together by Gamesa Electric

The refrigeration is of type IC-21; it consists of forced air ventilation by means of a centrifugal fan located in D.E of the rotor The inlet air is radial through windows located in the lateral art of the machine (N.D.E.) and the outlet air is radial through top air duct (D.E.)

The generator’s mounting arrangement is according to IM-4015, vertical mounting supported on lower shield and upper shield, upper bearing and lower bearing Main output terminals U, V and W, neutral terminals X, Y and Z, are accessible All the auxiliary components, control and monitoring devices have wire connections to

their respective terminal boxes

8.2.2 Stator Core

The stator core is insulated magnetic steel of 0.5 mm thicknesses and 4 W/kg at 1.5 Tesla, manufactured in compressed steel discs Each magnetic sheet has two-sided insulation to reduce the eddy current losses The set is clamped with two pressure plates, one on each side, together with the axial tie bars welded to the stator core It provides the necessary stiffness to the assembly

To improve the ventilation, the magnetic core is made of packages, separated from each other by ducts that form channels around where the air circulates radially The ducts provide an efficient air volume and reduce the losses

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The stator winding is provided by the insulation of mica tape and corona resistant tape, subjected to a process of impregnation (V.P.I.) with polyester-resin that removes totally the air, provides an excellent dielectric, a good stability to the heating and unaffected by the humidity, complying with class H insulation requirements

The insulation also possesses high electric strength, high resistance to moisture and aggressive gases and vapours, excellent mechanical stability and long life The both ends of each winding are connected to the main and a neutral terminal box respectively

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8.2.4 Insulation Class

The insulation class of stator is H ( 180ºC)

Note: Insulation systems are rated by standard IEC 60085, classified according to maximum allowable

This piece is totally machined and turned firmly with other pieces by the diamond tool fitting The form of the pole shoes and the stator winding are designed together to induce sine wave voltage

The rotor is designed to meet mechanical requirements as requested by the customers resulting in better performance and mechanical strength for a successful operation The mounting of the polar wheel on the shaft can be seen in the figure 3

Figure 3 Machined shaft with polar mounting wheel

The field coils insulation complies with Class H specifications

8.3.3 Excitation system

For Brushless machines, the function of the stator of the exciter is to supply the flux to the exciter rotor It is fed by DC which is controlled by the voltage regulator based on load requirements, which keeps the voltage constant

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Figure 4 The Excitation system scheme in brushless exciter

A radial fan fitted on the DE (driving end) shaft end activates the cooling of the stator and rotor coils

8.4 COMPLETE UPPER SHIELD N.D.E

The end shields at the drive and non-drive ends are disk shaped casting and arranged for taking the bearing assembly which is appropriate for the type and a type variant of the machine Upper shield NDE withstands the electromechanical and hydraulic forces produced by the rotating part of the generator The shield leans

on the housing of the stator and transmits the axial hydraulic forces produced by the turbine during its operation

The main components of the complete upper shield are as following:

8.4.1 Upper shield

The shield is made of welded steel plate to carbon of S275 JR quality This shield transmits the forces to the frame and provides a central part where the bearing and the oil tank are placed The upper shield can be seen in the Figure 2 represented as 3

8.4.2 Insulated sleeve bearing N.D.E

Sleeve bearings are used in the N.D.E supporting axial and radial loads

The bearing housing is finned flange mounted bearing type and the heat dissipation is done by the oil cooling Oil type corresponds with ISO VG 32

The specification for the N.D.E bearing is MICHELL AV14BNT3

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PO1250-O4D8

8.5 COMPLETE LOWER SHIELD D.E

The end shields at the drive end is disk shaped casting and arranged to withstand electromechanical forces produced by the rotating part of the generator The lower shield is fixed to the frame of the machine by means of bolts, as well as the sleeve bearing is fixed to the lower shield

The main components of the complete lower shield are as follows:

8.5.1 Lower shield

The lower shield is used as support of the lower sleeve bearing The lower shield is a structure consists of welded steel plates (S275 JR quality compliance) where the bearing is mounted in the centre The lower shield can be seen in the Figure 2 represented as 4

8.5.2 Sleeve bearing D.E

Sleeve bearings are used in the D.E supporting radial loads

The bearing housing is finned flange mounted bearing type and the heat dissipation is done by the oil cooling Oil type corresponds with ISO VG 32

The specification for the D.E bearing is MICHELL 13GT1

8.6 COOLING SYSTEM

The cooling of the active parts of the stator and rotor is done by forced ventilation (IC 21) The air forms a circuit opened through the machine, driven by a centrifugal fan located in the D.E part of the rotor The cold air is introduced from N.D.E towards D.E and the hot air is driven by means of the fan towards the outside

of the machine through an air duct

8.7 LUBRICATION / REFRIGERATION BEARING SYSTEM

8.7.1 Lubrication / cooling upper thrust bearing

The bearing losses produced during the operation of the machine are extracted of it by means of the cooling system

The losses generated during the operation are converted into heat and are removed by means of oil The cooling of the oil takes place by means of a heat exchanger (water cooler that is inside the oil tank) around which water flows from an outer circuit

MIN Water flow for cooling: 29.1 l/min

MAX Water flow for cooling: 35 l/min

Volume of oil in tank (approx): 55 litres

Water cooler connection NPT 3/4

Inlet temperature: 30ºC

Losses to be evacuated: 17.9 kW

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PO1250-O4D8

8.7.2 Lubrication / cooling lower guide bearing

The losses that are generated during the operation convert into heat and are dissipated by means of oil The oil and bearing are contained into the oil tank In order to cool the oil a water cooler is used (coil) that is also inside the oil tank

MIN Water flow for cooling: 12.3 l/min

MAX Water flow for cooling: 14.7 l/min

Volume of oil in tank (approx): 54 litres

BSPP MALE G3/4”

Inlet temperature: 30ºC

Losses to be evacuated: 3.9 kW

8.8 BRAKE SYSTEM

This machine is equipped with a brake system Brake system is used for:

• Reducing stop time due to inertia moments and reduced losses at low speed, hydraulic machines

have high natural stop times

• Avoid sleeve bearing working below transitional speed

• In case of water leakages in the turbine wicket gate, brake system holds the rotor under standstill

conditions

The brake system consists in one hydraulic brake calliper and a braking disk installed at N.D.E of the

generator, outside the housing and protected with a cover

The brake system is designed for the following conditions:

APLICATION

MAX INITIAL SPEED (r.p.m.)

FINAL SPEED (r.p.m.)

BRAKING PRESSURE (bar)

BRAKE TORQUE (Nm)

CASE 1 Stop the generator and keep the rotor stopped 150 0 70 2352

Brake pads should be reviewed and exanimated periodically The brake system is equipped with two Brake ON/OFF sensors

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Date:01/03/2021 Pg 24of78

PO1250-O4D8

8.9 OIL INJECTION SYSTEM FOR N.D.E BEARING

The high-pressure oil injection system is designed to form a lifting oil film between the runner surface mirror and the segments during the starting and shutdown Most friction is avoided and the safety against damages in the sliding surfaces increases considerably In addition, the over pressure of oil allows to move the rotor manually, due to the reduction of the friction, which is very desirable during the assembly or revisions

System features

System operating control:

• Pump turning in the correct direction suck oil and pump it inside all unit items Pressure is limited by safety valve

• Oil will be filtered when passes through the filter with an electrical clogging indicator This filter allows the filter cartridge change without having to stop the unit

• Pressure gauges include the isolating-valve for each protection Moreover, the system has pressure sensor to ensure the pressure control

• The flow to provide can be regulated by ball valves located in the outlet oil

• All items will be protected from overpressure by safety valve

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8.11 CONDITION MONITORING OF THE GENERATOR

Internal sensors are installed in most critical generator parts to provide the capability of have predictive information or diagnose the cause of a deteriorating situation This can reduce unplanned outage which translates into less operation and maintenance cost to the customer The generator is equipped with the following measuring and monitoring elements:

8.11.1 Stator winding sensors

The temperature of the stator winding is monitored by 6 thermostats (PT-100) embedded in the stator windings to protect the winding against thermal overloads

The number of installed sensors per phase is 2 These contacts must be adjusted to give alarm when exceeding 160ºC and discharging should happen when exceeding 165 ºC

Bearings oil levels are monitored as follows:

D.E Oil sump:

• 1 x Electrical switch gives alarm for high level

• 1 x Electrical switch gives trip for low level

N.D.E Oil sump:

• 1 x Electrical switch gives alarm for high level

• 1 x Electrical switch gives trip for low level

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Date:01/03/2021 Pg 26of78

PO1250-O4D8

8.11.3 Hydrostatic control devices

• The hydrostatic system is provided with one 3-phases asynchronous motor, 400 Vac, 3 kW, 50 Hz

• The system has 1 pressure switch to ensure the pressure control

• The system has 1 pressure switch, to check the filter clogging

8.11.4 Space heaters

The machines are fitted with space heaters to avoid water condensation during long periods of standing still; four units of space heaters are placed in proximity of end windings, which shall be energised in case generator is halted

• 1 x located in D.E bearing (radial)

• 1 x located in N.D.E bearing (radial)

• 1 x located in N.D.E bearing (axial)

8.11.7 Brake sensors

This generator is equipped with a brake calliper with two brake ON/OFF switches They must be adjusted to give alarm

8.11.8 Earth shaft brush

There is a brush to ground the generator shaft, locate in D.E side

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TV1-TV3: 10500/V3 // 100/V3 //100/3V

30 VA Cl 0.5

30 VA 3P

Measure and protection

Sensing current

Neutral terminal box

TA1-TA3: 1200/1-1A

15 VA Cl 0.5

15 VA 5P20

Measure and protection

8.11.10 Excitation

Excitation

3000 VA 10500/231 V

50 Hz

4350 VA (10s)

Feed AVR

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The following steps explain the way to fit the PO 1250-O4D8 generator in vertical position

STEP 1: Initial position With generator in horizontal position and tumbler device bolted to the D.E shield, securing the slings from the suspension beam on the bolted lifting lugs of the frame

STEP 2 & 3:

Lift the generator pulling from the lifting lug

of the suspension beam with the crane, at the same time move the crane horizontally The centre of gravity is approaching the vertical of the supporting point from the tumbler device

STEP 4:

With the generator in vertical position, once

it is introduced in the powerhouse, standing

on the floor and supported by the crane, unscrew the tumbler device

STEP 5:

Using the crane lift the generator and remove the tumbler device

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