Higher Secondary Level (Grade XI & XII) 2015 Electrical Engineering

Transcription

1 Curriculum Of Technical Subject Group Higher Secondary Level (Grade XI & XII) 2015 Electrical Engineering Higher Secondary Education Board Curriculum & Training Division Sanothimi, Bhaktapur 1

2 ELECTRICAL INSTALLATION OF COMMERCIAL AND INDUSTRIAL BUILDINGS Grade: XI Full marks: 100 (50T + 50P) Pass marks: 1(T) + 20(T) Period per week: 3(T) + 3(P) Teaching hours: 150[Theory (T)75 +Practical (P) 75] I. Introduction Every building project includes two key phases: the first of this is concerned primarily with the design and construction of the building-the floors, walls and roof; and in the second phase, electrical and communication services, heating, ventilating and air conditioning systems, public health and fire protection installations are covered. Electrical personnel for building services need to have an understanding of the industry standards applicable to electrical services and installations. They also need to understand the principles and processes used to design the electrical services in buildings. The aim of this course is to provide students with skills related to practical knowledge. The main focus of this subject is on theory with practical applications. Students can therefore understand the electrical installation standards and equipments. II. General Objectives After the completion of this course the students will be able:- to establish electrical and lighting requirements for buildings and select design conditions. to design electrical and lighting installation for specific applications. to provide knowledge about electricity distribution, safety and fire protection to understand the requirements for special and hazardous locations. to deliver knowledge about inspections, testing and certification of electrical installations. III. Course Contents Theory Specific Objectives Explain the cost estimation of electrical installation Explain the calculation of lighting schemes for residential and commercial buildings Contents Unit 1. General Principles 1.1 Estimating: estimate of quantities and cost analysis 1.2 Familiarization of catalogues 1.3 Recording of estimate 1.4 Determination of required quantity of material 1.5 Determination of cost of material and labour 1. Contingencies and overhead charges Unit 2. Design of Illumination Scheme for Residential and Commercial Buildings 2.1 Introduction. 2.2 Terminology in illumination 2.3 Laws of illumination 2.4 Various types of light sources 2.5 Practical lighting schemes Lighting arrangement Contact Hours 10 2

3 Get familiarize with design consideration for Electrical Installation in buildings and Electricity Rule Understand electrical supply system for industrial buildings Study about different types of luminaries and lighting systems Illumination for different occupancies Selection of luminaries. 2. Methods of calculation Unit 3. Design Consideration of Electrical Installation in Buildings 3.1 Electric supply system: single phase two wire and three phase four wire systems 3.2 Protection of electrical installation against overload, short circuit and earth fault 3.3 General requirement of electrical installation Electricity rules Testing of installation Neutral and earth wire Service connections Sub-circuits Location of outlets, control switches, MDB and SDB 3.4 Design of MDB and SDB 3.5 Design of lighting and power sub circuits 3. Guidelines for installation of fittings 3.7 Load assessment 3. Selection of cable size, wires and permissible voltage drop. 3.9 Design electric circuits with and without relays 3.10 Schematic (layout) and wiring diagram Unit 4. Introduction to Electrical Supply System for Industrial Buildings 4.1 Electric Load Estimate 4.2 Load Centre 4.3 Supply System for Industrial Plant 4.4 Classification of Electrical Installation for Industrial Building 4.5 Reading and Interpretation of Building Drawing 4. Electrical Rules related to Electrical Installation & Testing Unit 5. System Components for Industrial Illumination 5.1 Light Sources Incandescent Filament Lamps Fluorescent Lamps High Intensity Discharge Lamps LED Lamps Types Luminaries 4 3

4 Get familiarize with design principles of different illumination schemes Study of outdoor lighting system design Design of industrial power supply system 5.2 Types of Industrial Lighting Systems Factory Lighting for Visual Tasks Security Lighting Emergency Lighting Unit. Illuminating Design Principle.1 Basic Consideration for Illuminating Design Space Function Provision of Quality and Quantity of illumination Selection of Lighting Systems, Sources, Luminaries, and Controls Definitions of Terminology.2 Lumen Method of Lighting computations.3 Point-to-point Lighting Computation.4 Design Procedures Unit 7. Out-door Lighting System Design 7.1 Introduction 7.2 Selection of Street Light Sources 7.3 Selection of Luminaries 7.4 Design Procedure of Street Lighting Scheme 7.5 Basic Floodlighting Effects 7. Selection of Floodlight Sources 7.7 Design Procedures 7. Application Guide: Buildings and color considerations, Examples of flood lighting installation. Unit. Electrification of Industrial Building.1 Concept of Industrial Installation.2 General rules guidelines for wiring of Industry.3 Installation and positioning of equipments..4 Principles of circuit design in power circuits..5 Energy and power requirement for Lift, conveyor-belt and HVAC. Procedures to design circuits and deciding the number of circuits..7 Methods to draw single line diagram.. Selection of type of wiring and rating of wires & cables..9 Load calculations and selection of size of conductor..10 Selection of rating of main Panel Board and distribution board,.11 Protective switchgears- HRC Fuse, MCB, MCCB and accessories 4

5 Design earthing system for commercial and industrial buildings Study about cables and terminations used in industrial and commercial power supply systems Study the distribution substation of industrial power supply system Get familiarized with emergency and back-up power supply system for industrial and commercial installations Unit 9. Earthing System for Commercial and Industrial Building 9.1 Introduction 9.2 System & Equipment Earthing Point to be Earthed Factors Influencing the earth resistance Method of reducing earth resistance 9.3 Methods of Earthing 9.4 Earthing for Lightning Protection Unit 10. Cables and Terminations 10.1 Cables Cable construction Types of cables Cable Ratings: voltage rating & conductor size Installation of cable Locating cable faults 10.2 Connectors and terminations Types of connectors and applications Types of terminations and methods Splicing devices and techniques Unit 11. Distribution Substation of Industrial Plan 11.1 Introduction 11.2 Classification 11.3 Indoor substations 11.4 Out-door substations 11.5 Selection and location of site 11. Schematic diagram of distribution substation 11.7 Equipment and measuring accessories for substations and switch gear installation Unit 12. Emergency and Back-up Supply System for Industrial Plant 12.1 Battery Supply System Battery Installation Charging and Maintenance 12.2 Emergency Supply System 12.3 Uninterrupted Supply for Critical Load

6 IV. Course Contents Practical Contact Practicals Hours 1. Draw the electrical symbols and standards 2. Layout of distribution system of electricity ( From 11kV to end used) 3. Draw the single line and connection diagrams of electric light and power circuit 4. Demonstrate wiring accessories such as switches, socket, distribution board etc, 3 protective devices such as fuse, HRC fuse, MCB s, MCCB,s etc their construction, function and application. 5. Preparing electrical layout and details for residential, commercial and industrial building. Conducting market study and collecting informative brochures and specification on various product available about electrical lamp, appliances and equipments 7. Design electrical Installation scheme for residential building. Draw detail wiring diagrams. Prepare report and drawing sheets (Light circuit Design, Power circuit Design and Detail Design of Distribution System). Design electrical Installation scheme for commercial building. Draw detail wiring diagrams. Prepare report and Drawing sheets (Light circuit Design, Power circuit Design and Detail Design of Distribution System) 9. Design electrical Installation scheme for Industrial building. Draw detail wiring diagrams. Prepare report and Drawing sheets (Light circuit Design, Power circuit Design and Detail Design of Distribution System) 10. PVC and Metal Conduit wiring in Cubical Installation of: pipe, junction box, tee and reducer fluorescent tube light fixture, CFL, LED lamps and switches MCB, MCCB and ELCB 5/15 Amps switch socket 11. Study of different types of sources of light and make connections, and to measure intensity of light with lux-meter: Fluorescent lamp HP mercury vapour lamp HP sodium vapour lamp Compact Fluorescent lamp (CFL) V. Instructional Materials: To be guided by Teaching Manual VI. Instructional Techniques: To be guided by Teaching Manual

7 VII. Marks and hours distribution Groups Unit Marks Distribution Number of Hours Theory Theory Group A Group B Group C 10 7 Group D Group E Total VIII. Evaluation Schemes a) Theory Evaluation: S. N. Topics No. of Questions Marks Total 1 Very Short Questions Short Questions Long Question (Analytical) Total 50 b) Practical Evaluation: Internal Evaluation Marks External Evaluation Marks Lab Exercises are guided by marks distribution and Teaching Manual. Practical Internal Examination Evaluation Scheme (30 Marks) Internal evaluation will be conducted by course teacher based on following activities: 1) Attendance and Class Performance 5 Marks 2) Lab/Field/Case Study Report 5 Marks 3) Practical First Exam 10 Marks 4) Practical Second Exam 10 Marks Total 30 Marks Practical External Examination Evaluation Scheme (20 Marks) 1) Practical Exam 15 Marks 2) Viva voce 5 Marks Total 20 Marks IX. Reference Books: 1) J. B. Gupta, Electrical Installation Estimating and Costing, New Delhi, S.K.Kataria & Sons. 2) G. L. Wadhwa, Generation, Distribution and Utilization of Electrical Energy, India, New Age International Pvt. Ltd. 3) S. L. Bhatia, Handbook of Electrical Engineering. 7

8 CONTROL AND PROTECTION OF INDUSTRIAL POWER SUPPLY SYSTEM GRADE: XI Full Marks: 100 (50T + 50P) Pass Marks: 1(T) + 20(P) Periods per week: 3(T) + 3(P) Teaching Hours: 150 [Theory (T) 75 + Practical (P) 75] I. Introduction The operation, control and protection industrial and commercial electricity supply system is very important. This course covers the common operational issues encountered by the concerned technicians and provides them fundamental knowledge related to the control and operational strategy. Detail deliberations on control and protection systems and devices will strengthen the theoretical base and also provides practical skills required for design and operation of control and protection of industrial power supply systems. II. Objectives After the completion of this course, the students should be able: - to observe the constructional details of fuses, MCB, MCCB, ELCB, RCCB, isolators, CT and PT to identify, select and operate fuses, MCB, MCCB, ELCB, RCCB, isolators, CT and PT to observe constructional details of various types of relays and protection systems used in electrical power supply systems and industrial plants, to operate, identify and select various types of relays and protection systems used in electrical power supply systems and industrial plants, to measure soil resistance (resistivity); and design and install earthing system for industrial and commercial installations to observe the constructional features of ACB; to identify, select and operate ACB to observe the operation of VCB and OCB III. Course Contents Theory Specific Objectives Explain background and provide introduction to control and protection of electricity supply systems; need for and requirements of control and protection system Contents Unit 1: Introduction to Control and Protection System 1.1 Need for control and protection of electricity supply systems 1.2 Nominal ratings and abnormal conditions of electrical equipment 1.3 Short-circuit and open circuits; their harmful effects 1.4 Requirements of a protection system 1.5 Definitions of terminologies used in control and protection of electricity supply systems: switches, load break switches, fuses, isolators, contactors, circuit breaker Contact Hours

9 Familiarize with Construction and operating principles of isolators and contactors used in electricity supply systems Familiarization with CTs and PTs, their construction and operating principles Understand basic construction and operating principles of various types of circuit breakers used in electricity supply systems Impart the information on constructional details and operating principles of relays in electricity supply systems Provide basic knowledge on different types of protection schemes used in electricity supply systems Unit 2: Isolators and Contactors 2.1 Isolators: construction, operating principles, and their selection; applications 2.2 Contactors: types, construction, operation; control and protection of circuits using contactors; contactors with pneumatic and electromagnetic drives; interlocking of contactors and their applications Unit 3: Current and Potential Transformers 3.1 Potential transformers: Construction, operating principles, characteristics, standard ratios, burden, errors and applications; common faults and their detection techniques 3.2 Current transformers: Construction, operating principles, characteristics, standard ratio, errors, burden, errors and applications; common faults and safety precautions to be taken when working with energized CTs. Unit 4: Circuit Breakers 4.1 Introduction, basic operating principles, arc phenomena and arc extinction in circuit breakers, duties of circuit breakers 4.2 Classification, construction, operating principles, characteristics and applications of circuit breakers: Air break circuit breakers Oil circuit breakers Air blast circuit breakers vacuum circuit breakers SF circuit breakers Unit 5: Relays 5.1 Classification of relays: electromagnetic, static and numerical relays 5.2 Electromagnetic relays: Construction, operating principles and classifications based on characteristics (Instantaneous relays, inverse relays, IDMT relays ), Plug setting and time setting of relays 5.3 Directional relays: basic philosophy 5.4 Basic introduction to static and numerical relay 5.5 Buchholz relay: construction, operating principles, characteristics Unit : Protection Schemes.1 Application of IDMT relay for HV feeder protection, time graded and current graded protection

10 Enable students to compute short circuit fault current and MVA levels in electricity supply systems Enable students to understand different types of earthing systems and overvoltage protection schemes.2 Earth fault detection schemes residual CT connection core balance earth lead.3 Application of directional relay in loop feeders.4 Basic principle of distance protection and protecting zone.5 Differential protection schemes for transformers generators and motors. Buchholz relay for transformer protection alarm and tripping circuits Unit 7: Short Circuit MVA and Current 7.1 Short circuit faults: origin and effects 7.2 Concept of short circuit fault current and fault MVA 7.3 Short circuit in a generators Types of short circuit fault Possibility of occurrence and sensitivity based on magnitude Calculation of 3-phase symmetrical faults on unloaded generators Faults in generator windings Short circuit in a distribution feeder Types of short circuit fault Possibility of occurrence and sensitivity based on magnitude Calculation of simple 3-phase symmetrical faults Unit VIII: System Earthing and Overvoltage Protection.1 Earthing: Definition, purposes, classification, methods of earthing, earthing resistance, earth fault protection.2 Causes of overvoltages in electricity supply system, lightning and protection from lightning.3 Overvoltage protection: overhead earthwire angle of protection, horn gap and rod gap, lightning arrestor, surge arrestors.4 Neutral earthing: isolated neutral, solidly grounded neutral, resistance earthing, reactance earthing, Peterson coil earthing.5 Substation earthing: safe value of current through human body, soil resistivity and resistance, step and touch potential, grounding methods in substations

11 IV. Course Contents Practical Practicals Contact Hours 1) Study of time current characteristics of different types of fuses and MCBs 3 2) Basic protection circuit design for a general household, coordination of fuses 3 or fuse and MCB 3) Identification of different components of protection system in electricity supply systems 3 3) Identify terminals and carry out polarity test and ratio test for a potential transformer 3 4) Identify terminal and carry our polarity test and ratio test, and plot magnetization curve 3 for a current transformer 5) Observe and identify terminals of different types of relays 3 ) Draw time current characteristics of different types of relays 7) Test a residual earth fault protection relay for its operating characteristics 3 ) Test a sensitive earth fault protection relay and plot its operating characteristics 3 9) Study various components of Air Circuit Breaker, its trip circuit and observe its operating characteristics 10) Study various components of Oil Circuit Breaker, its trip circuit and observe its 3 operating characteristics 11) Study various components of Vacuum Circuit Breaker, its trip circuit and observe its 3 operating characteristics 12) Study various components of SF Circuit Breaker, its trip circuit and observe its 3 operating characteristics 13) Test a differential protection scheme for transformer 3 14) Study protection schemes of a nearby substation, draw a single line diagram and 15 observe operation of different components of the protection system 15) Design a protection system for feeders, generators and transformers 12 V. Instructional Materials: To be guided by Teaching Manual VI. Instructional Techniques: To be guided by Teaching Manual VII. Marks and hours distribution Number of Marks Distribution Groups Unit Hours Theory Theory Group A Group B Group C Group D Group E Total

12 VIII. Evaluation Schemes a) Theory Evaluation: S. N. Topics No. of Questions Marks Total 1 Very Short Questions Short Questions Long Question (Analytical) Total 50 b) Practical Evaluation: Internal External Evaluation Marks Evaluation Marks Lab Exercises are guided by marks distribution and Teaching Manual. Practical Internal Examination Evaluation Scheme (30 Marks) Internal evaluation will be conducted by course teacher based on following activities: 1) Attendance and Class Performance 5 Marks 2) Lab/Field/Case Study Report 5 Marks 3) Practical First Exam 10 Marks 4) Practical Second Exam 10 Marks Total 30 Marks Practical External Examination Evaluation Scheme (20 Marks) 1) Practical Exam 15 Marks 2) Viva voce 5 Marks Total 20 Marks IX. Reference Books: 1) M. K. Pandey, Power system control and protection, Kathmandu, Nepal, ) R. N. Smeaton, The art and science of protective relaying, ) J.B. Gupta Switchgear & Protection S.K. Kataria & Sons, India, ) Sunil S. Rao Switchgear Protection and Power Systems Khanna Publishers, India

13 OPERATION AND MAINTENANCE OF MICROHYDRO PLANT AND PHOTOVOLTAIC SYSTEM Grade: XII Full marks: 100 (50T + 50P) Pass marks: 1(P) + 20(P) Period per week: 3(T) + 3(P) Teaching hours: 150[theory (T) 75 + Practical (P) 75] I. Introduction This course deals with the introduction to Micro-Hydropower (MHP) and photovoltaic system for energy generation. Study their operating principles and get familiarize with the functions of different components involved. This course also deals with implementing effective methods for their maintenance ensuring continuous operation of the plant and supply of electricity. II. Objectives After the completion of this course the students will be able to:- introduce the knowledge of micro hydro and photovoltaic energy conversion systems with their market potential and importance enable students identify various components involved in both micro hydro and photovoltaic system enable students operate a micro hydro plant and photovoltaic system and adopt suitable methods for their maintenance. III. Course Content Theory Specific Objectives Introduce hydropower and identify the need of MHP Familiarization with layout and components in MHP plant Explain the working principle and identify various electromechnical components Contents Unit 1: Introduction 1.1 Classification of hydro power plant by head and capacity 1.2 Features of Micro Hydro Power (MHP) plant 1.3 Role of MHP plant for rural development 1.4 Status of MHP in Nepal Unit 2: Layout and Civil Construction Works of MHP Plant 2.1 Basic layout of a MHP plant 2.2 Principle of power generation - Definition of head and discharge, Power equation. 2.3 Components of MHP Plant, their constructional details and functions intake and weir, desilting basin and spillway, forebay, Penstock, Power house and tail race. Unit 3: Electro-Mechanical Component of MHP Plant 3.1 Turbines and valves Types of turbine and their working principle, turbines for MHP plants, types of valve used in MHP plant. 3.2 Synchronous generator Basic construction and Contact Hours

14 Implement protection schemes of MHP plant Learning the procedures to operate and maintain a MHP plant Introduce solar energy, its need and potential Effective use and handling of radiation measuring instruments working principle, Excitation system. 3.3 Induction (asynchronous) generator - Basic construction and working principle, requirement of excitation capacitor. 3.4 Coupling of turbine and generator - Direct coupling, Belt drive, Flywheel. 3.5 Speed Governing Hydraulic mechanical governor, Electronic Load Controller (ELC) Basic operating principle 3. Voltage control AVR for synchronous generator Unit 4: Protection System for MHP Plant 4.1 Over speed protection 4.2 Over-load and short-circuit protection for generator 4.3 Over voltage and under voltage tripping system 4.4 Earthing for generator neutral and body 4.5 Protection of generator and ELC from lightening stroke 4. Single-line diagram of control panel with protection devices Unit 5:Operation and Maintenance of MHP Plant 5.1 Starting up and shutdown procedure of MHP, training of operator. 5.2 Regular maintenance procedure for intake weir, canal, desilting basin and spillway, forebay, penstock, turbine, valve and generator. 5.3 Regular inspection and maintenance of control panel, switchgear and transformers Unit : Introduction to Solar Energy.1 Introduction to Sun and its energy potential.2 Role of PV system in rural development.3 Current status of PV system in Nepal and its future scope.4 Cummulative installed capacity of photovoltaic system around the world Unit 7: Solar Radiation, Orientation and Measurement 7.1 Some common terms- Insolation, Solar Constant and Air Mass, Solar azimuth and Solar Elevation Angles 7.2 Spectral distribution, factors affecting spectral Distribution 7.3 Types of Radiation(direct, diffuse and reflected), Global Solar Radiation 7.4 Orientation and tilt angles for solar panels, latitude 4 14

15 Get familiarized with performance specifications related to pv cell and learn various effects that hinder their performance. Identify various technologies in PV market Identify various systems required for utilizing solar energy and longitude Selecting optimum Tilt angle for solar panels 7.5 Pyranometer, its construction, working principle and calibration 7. Pryheliometer, its construction, working principle and calibration 7.7 Data logger, its function and block diagram Unit : Photovoltaic Cell and Performance Parameters.1 Ideal and practical PV cell, their equivalent circuits, IV and P-V curves.2 Effect of series and parallel resistance on PV cell characteristics.3 Fill factor and efficiency.4 Series and parallel connection of PV cells.5 Factors affecting solar cell performance Effect of cell temperature and Insolation on cell characteristics Effect of humidity on output power Shading and its impact on PV cell performance. Mitigation of shading impact (Use of bypass and blocking diode) Unit 9: PV Technologies 9.1 Comparison between conventional and thin film Technology 9.2 Crystalline silicon technology (m-si, p-si), advantages and disadvantages, 9.3 Thin film technology (a:si, CdTe, CIS), advantages and disadvantages Unit 10: PV System, its Components and applications 10.1 Solar module/array, Various Components of a solar module Connecting multiple solar modules (Series, Parallel, Series-parallel) 10.2 Commonly available solar modules in Nepal, Standard ratings 10.3 Array and its arrangement techniques 10.4 Mounts and mounting techniques (roof, ground and tracking) 10.5 Storage devices/batteries, types of batterieslead acid (tubular and flat-plate batteries), nickel cadmium, nickel iron, lithium-ion Battery connection techniques (Series, Parallel, Series-Parallel combinations) 10. Charge controllers- PWM and MPPT charge

16 Implement, plan and schedule for and maintenance controllers 10.7 Inverters (sine and square wave) 10. Different topologies of PV system, their advantages and disadvantages Centralized Master Slave String Team-concept Multi-String Modular 10.9 Isolated PV system PV system for street lighting PV water pumping system Unit 11: Operation and Maintenance of Photovoltaic System 11.1 Regular cleanliness of solar panels 11.2 Checking battering overfill and prevent corrosion, testing of batteries 11.3 PV system safety measures during operation 11.4 PV module recycling and disposal IV. Course Contents Practical Practicals Contact Hours 1. Studying various components of a Microhydro system Understanding and drawing single line diagram of a Microhydro Power Plant 3 3. Experimental study on induction generator a. Study of voltage build-up at no-load b. Operation with purely resistive load c. Operation with inductive load and effect on terminal voltage 4. Experimental study on Electronic load controller in lab. 5. Testing PV cells, its IV curve using variable resistors, ammeters and voltmeters.. Measure the effect of shunt and series resistance on solar cells using 7. Series and parallel connection of PV modules, Measuring of resulting current, voltage and power using ammeter, voltmeter and wattmeter.. Measuring the effect of cell temperature (at least three different temperatures) on IV 9 and PV curve. 9. Measuring the effect of Insolation on IV and PV curve (at least three different 9 Insolation values). 10. Measuring solar radiation using pyranometer and comparing the result with solar 3 constant and determine the radiation loss. 11. Calculation of energy output from a solar panel under different Orientation and Tilt angles. 12. Demonstrating the shading impact on the output of PV modules Study the use of MPPT based charge controller on a real system. 14. Study the use of Data Logger on a real system. (3 hours) 3 4 1

17 V. Instructional Materials: To be guided by Teaching Manual VI. Instructional Techniques: To be guided by Teaching Manual VII. Marks and hours distribution Groups Unit Marks Distribution Number of Hours Theory Theory Group A Group B Group C Group D Group E Total VIII. Evaluation Schemes c) Theory Evaluation: S. N. Topics No. of Questions Marks Total 1 Very Short Questions Short Questions Long Question (Analytical) Total 50 d) Practical Evaluation: Internal Evaluation Marks External Evaluation Marks Lab Exercises are guided by marks distribution and Teaching Manual. Practical Internal Examination Evaluation Scheme (30 Marks) Internal evaluation will be conducted by course teacher based on following activities: 1. Attendance and Class Performance 5 Marks 2. Lab/Field/Case Study Report 5 Marks 3. Practical First Exam 10 Marks 4. Practical Second Exam 10 Marks Total 30 Marks Practical External Examination Evaluation Scheme (20 Marks) 1. Practical Exam 15 Marks 2. Viva voce 5 Marks Total 20 Marks 17

18 IX. Reference Books: 1. Adam Harvey, Micro-Hydro Design Manual A guide to small-scale water power generation, Intermediate Technology Publication, Maintenance and Repair Manual for private Micro Hydro power plants, ICIMOD, Kathmandu, Nepal, Operation and Management Manual for private Micro Hydro power plants, ICIMOD, Kathmandu, Nepal, G. M. Masters, Renewable and efficient electric power system, John Wiley & Sons, Inc., New Jersey, A. K. Mukherjee, Applied Photovoltaic Engineering, PHI, Delhi,

19 REPAIR AND MAINTENANCE OF ELECTRICAL EQUIPMENTS Grade: XII Full marks: 100 (50T + 50P) Pass marks: 1(T) + 20(P) Period per week: 3(T) + 3(P) Teaching hours: 150[Theory (T) 75+Practical (P) 75] i. Introduction Breakdown of electrical equipment and machine is common phenomenon which shortens their useful lives. It is very important to diagnose and carry out required repair and maintenance of these equipment and machines. This course is intended to provide the students knowledge and skills to carry out diagnosis and repair/maintenance of common electrical equipment and machines. There will be continuous revision of general constructional features and operating principles of common electrical equipment and machines like transformers, motors, fans, control panels, pumps. ii. Objectives: After the completion of this course the students will be able to:- Understand and perform maintenance of domestic and industrial equipment and Machines; Perform and supervise work on repair and maintenance of various types of electrically operated home appliances as well as industrial machines and equipments; Follow proper maintenance procedures when carrying out repair/maintenance works; Follow safety instructions necessary for electrical repair and maintenance works. iii. Course Contents Theory Specific Objectives Introduce maintenance; emphasize the need for and regulations; types of maintenance Introduce general diagnostic procedures and maintenance practices Give general introduction to repair Contents Unit 1: Introduction 1.1 Need for regulation maintenance 1.2 Causes of deterioration: ingress of moisture, contamination, corrosion, mechanical stress, electrical faults, insulation ageing, system surges, overheating 1.3 Types of maintenance-preventive, routine or breakdown Unit 2: Diagnostics and Maintenance 2.1 Inspection of appliances by visual, audio, smell to identify the problems and faults. 2.2 General overhaul-dismantle, clean, lubricate, assemble and test. 2.3 Regular maintenance schedule Unit 3: General Introduction to Repair 3.1 General repair 3.2 Shutdown repair 3.3 Speeded-up repair Contact Hours Provide general introduction to Unit 4: Testing

20 testing of electrical equipments; types and procedures of testing of electrical equipments Introduce general electrical safety rules and regulations; inspection and testing of wiring systems; replacement and maintenance of wiring systems. Introduce general procedures for repair and maintenance of electrical appliances; dismantling, cleaning, diagnosis and repair of electrical appliances. Introduce motorized electrical appliances; procedures for repair and maintenance of motorized electrical appliances 4.1 Explanation of purpose and procedure for following test, Practice of following tests on various appliances: Continuity test Short circuit test Open circuit test Insulation test Polarity test Earth resistance test Voltage drop test Body leakage test Unit 5: Maintenance of wiring system 5.1 Rules and regulations on electrical safety, use of the permit to work system. Details to be entered on the permit: authorizing person, equipment to be worked on, work to be done, name of competent person, switching and isolating procedures, position and numbers of earth, position of CAUTION and DANGER notice, date and time of issue and cancellation. Lockout/tagout procedure. 5.2 Perform inspection and maintenance of Campus wiring system: Distribution boards, feeders, junction box, sockets, cable-wires, terminal strips, fuses, circuit breaker, etc. 5.3 Perform cleaning of wiring accessories. 5.4 Replace overheated wires, cables, jugs, sockets, junction box, terminal strips, etc. 5.5 Service and repair lighting installation. 5. Distribution Board: inspect and replace faulty and overhead element, cleaning up dust and carbon deposit, cleaning and tightening the contacts. Unit : Appliances Maintenance and Repair.1 Routine maintenance of appliances based on heating working principle such as-flat iron, toaster, kettle, hot plate, room heater, cooking range, geyser, oven, etc..2 Dismantling, cleaning, tightening, loose connection, replace faulty parts, tracing the circuit diagram, understand the function of each parts, resetting thermostat, assembling and testing..3 Fault finding exercises on above appliances. Unit 7: Maintenance and Repair of Motorised Appliances 7.1 Routine maintenance of motorised appliances such as fan, vacuum cleaner, water-pump, rilling machine, fan heater, etc

21 7.2 Dismantling, cleaning, tightening loose connection, lubricating, replace or repair faulty parts, checking the moving contacts, tracing circuit diagram, understand the function of each parts, assembling and testing. 7.3 Fault finding exercise on above appliances. IV. Course Contents Practical Practicals 1. Maintenance and repair of existing transformer Open short circuit and body leakage test of two winding, multi winding taped winding and trace the fault. Study the finding and consult instructor. Dismantle the core and coils Take data of each coils size of wire and number of turns compare with the enamel wire data table. Clean and assemble Rewind coils of appropriate size, material, number of turns and fix tag on beginning and ends Assemble core and coils together Test continuity and body leakage, coil to coil leakage test Varnish the transformer and dry it, assemble body Connect the proper load and run for load test. 2. Repair and maintenance of household appliances Check the name plate ratings and types of circuit of the appliances. Identify problem from customer of appliances like flat iron, toaster, kettle, hot plate, room heater, cooking range, geyser, oven, etc. Visual inspection to determine the causes of defects in the appliances. Dismantling, cleaning, tightening of loose connection; Tracing the circuit diagram, and understanding the function of each parts Replacement of faulty parts Resetting thermostat and of the appliance assembling Testing and upon satisfactory performance wind up the job. 3. Maintenance and Repair of motors Identify problem from customer, visual inspection for loose parts loose connection, broken parts, burn outs, jams. Check continuity and leakage No load test Load test Dismantle universal motor of drill machine, hand saw machine, hand grinder clean and inspect armature, field coil, commutator, bearings shape carbon brush, assemble and test run. Dismantle single phase capacitor start induction motor, clean and inspect squirrel cage rotor, test stator windings, capacitor centrifugal switches, distinguish starting windings and running windings. Grease the bearing, assemble and test run. Contact Hours

22 Dismantle a 3 phase induction motor, clear and inspect squirrel cage rotor, test state rewinding, find type of winding- change of grease bearings Assemble and test run. 4. Rewinding stator of motor [1] Capacitor start motor, running and starting winding, capacitor centrifugal switch. Name plate data power output voltage, frequency, connection, rpm, full load, phase, number full load current insulation type, manufacture model no. No of poles Pitch of coil no of slots that each coil spans No of turn in each coil Size of wire in each winding Kind of connection (series- parallel) Position of windings in relation to other windings Type of winding (hand, form skein) Slot insulation both size and kind Number of slots Stripping the stator Magnet wires (enamel wire) Slots insulation insulation class, insulation material, size cuffed ends Rewinding- Hand rewinding, form winding, skein winding Connection of winding single voltage, double voltage series parallel Recognize the connection Splicing and taping leads Testing new winding Backing and varnishing 5. Rewinding of Armature [15] Data taking and stripping armature Insulating core Making coils in the slots Connection the coils to the commutator Testing Turning the commutator in lathe Backing and varnishing Lap winding wake winding Armature with one coil, two coil and three coil per slots Commutator pitch and soldering the commutator Banding the Armature Balancing the Armature Dismantle armature from drill machine or vacuum machine take data and strip the winding, insulate the slots, make coils or wound it step by step. Balance test and varnish it. V. Instructional Materials: To be guided by Teaching Manual VI. Instructional Techniques: To be guided by Teaching Manual VII. Marks and hours distribution

23 Number of Marks Distribution Groups Unit Hours Theory Theory Group A 2 3 Group B Group C Group D Group E Total VIII. Evaluation Schemes e) Theory Evaluation: S. N. Topics No. of Questions Marks Total 1 Very Short Questions Short Questions Long Question (Analytical) Total 50 f) Practical Evaluation: Internal External Evaluation Evaluation Marks Marks Lab Exercises are guided by marks distribution and Teaching Manual. Practical Internal Examination Evaluation Scheme (30 Marks) Internal evaluation will be conducted by course teacher based on following activities: 5) Attendance and Class Performance 5 Marks ) Lab/Field/Case Study Report 5 Marks 7) Practical First Exam 10 Marks ) Practical Second Exam 10 Marks Total 30 Marks Practical External Examination Evaluation Scheme (20 Marks) 3) Practical Exam 15 Marks 4) Viva voce 5 Marks Total 20 Marks IX. Reference Books: 1. R. Rosenberg, Electrical Motor repair, Delmar Cengage Learning ; 3rd revised edition, UK. 2. Electrical trade theory, CIMI, Chennai, India. 3. K.B. Bhatia, Practical AC and DC motor rewinding, Oscar Publications, India. 23

24 4. U.S. Eswar, Handbook of Electrical motor control system, Tata McGraw-Hill, India, S.K. Sharotri, Preventive Maintenance of Electrical Apparatus, Katson Publishing, New Delhi.. F.G. Thompson, Electrical Installation and Workshop Technology, Longman, London,