Course Profile Transportation Technology, Grade 11, Workplace Preparation, Catholic and Public

Unit 4: Vehicle Electrical Systems

Time: 30 hours

Activity 4.1 | Activity 4.2 | Activity 4.3

Unit Description

Students acquire fundamental knowledge and skills for use in diagnosing and repairing the electrical systems found on most vehicles. Students begin by studying basic electrical principles and troubleshooting techniques. Students complete tasks at electrical workstations, develop skills in reading wiring diagrams, and perform system diagnosis and service. The final activity requires students to utilise knowledge and skills developed in the previous activities when describing, diagnosing, and servicing the starting and charging system. Cross-curricular opportunities exist in the areas of science and math. The advantages of becoming a reflective and creative thinker in this challenging subject area are stressed.

Unit Synopsis Chart

Activity	Time	Expectations	Assessment	Tasks
4.1 Electrical Fundamentals	600 min	TFV.02, TF2.01, SPV.01, SPV.02, SPV.03, SPV.05, SP1.04, SP2.01, SP2.03, SP2.04, SP3.01, ICV.02, ICV.05, IC2.01, IC2.02, IC3.02	Knowledge/ Understanding Thinking/ Inquiry Application	Students: - demonstrate knowledge and understanding of basic electrical theory; - construct, analyse, and repair automotive electrical circuits; - interpret wiring diagrams.
4.2 Starting System Diagnosis and Service	600 min	TFV.02, TF2.01, SPV.01, SPV.02, SPV.03, SP2.01, SP2.03, SP2.04, SP3.01, SP4.02 ICV.02, IC2.01, IC2.02	Knowledge/ Understanding Thinking/ Inquiry Application	Students: - demonstrate knowledge and understanding of starting system theory of operation; - locate testing procedures; - diagnose starting system problems.
4.3 Charging System Diagnosis and Service	600 min	TFV.02, TFV.03, TF2.01, SPV.01, SPV.02, SPV.03, SP1.04, SP1.05, SP2.01, SP2.03, SP2.04, SP3.01, SP4.02, SP4.03, ICV.02, IC2.01, IC2.02	Knowledge/ Understanding Thinking/ Inquiry Application	Students: - demonstrate knowledge and understanding of charging system theory of operation; - locate testing procedures; - diagnose starting system problems.

Activity 4.1: Electrical Fundamentals

Time: 600 minutes

Description

This activity involves the construction, diagnosis, and repair of a 12-volt electrical lighting circuit. Students design and construct a functional vehicle lighting system using a teacher-supplied wiring schematic, soldering tools, crimp-type connectors, shrink tube, pigtail sockets, and other items associated with any basic, functioning, electrical circuit. Discussions on battery design, function and safety, as well as the theory of electricity and current flow are important outcomes in this activity. Students read and utilize wiring diagrams in designing series, parallel, and series-parallel circuits to complete their project. All topics are covered in class with teacher-directed lessons and demonstrations, as well as in the lab with student-centred practise and performance tasks.

Strand(s) & Learning Expectations

Strand(s): Theory and Foundation, Skills and Processes, Impact and Consequences

Overall Expectations

TFV.02 - explain the use of each component of a vehicle system;

SPV.01 - function effectively both as individuals and as members of a cooperative team to service
and repair vehicles;

SPV.02 - apply the technological principles of input, process, and output in troubleshooting
vehicle systems;

SPV.03 - use current technology (e.g., on-line information from manufacturers, CD-ROM manuals, computerized diagnostic tools) when servicing, repairing, and modifying vehicles;

SPV.05 - use mathematical and language skills effectively and apply scientific principles to help solve transportation technology challenges;

ICV.02 - follow safe work practices in the transportation sector workplace, including safety procedures and practices and the use of protective clothing and gear;

ICV.05 - describe and evaluate the employability skills required to be successful in the workplace.

Specific Expectations

TF2.01 - analyse and describe the use of each of the following components of a vehicle: the chassis, frame, and body; the engine system; the fuel system; the electrical/electronics system; the gear and power train system; the steering system; the brake system; and the suspension system;

SP1.04 - develop a plan of procedures that indicates the steps required when repairing or
servicing a vehicle;

SP2.01 - use effectively, store safely, and maintain in good working order measurement, hand, power, machine, and pneumatic tools and equipment required for basic service tasks;

SP2.03 - systematically troubleshoot basic service problems on vehicles by organizing the variables into the following categories: input, process, and output;

SP2.04 - access and apply information from manuals, software databases, on-line information, and computerized diagnostic tools when troubleshooting and repairing components;

SP3.01 - correctly interpret assembly drawings that depict the components of a vehicle’s systems;

IC2.01 - work safely when performing tasks in the transportation sector;

IC2.02 - use all required protective clothing and gear (to protect the eyes, ears, hands, head, feet and respiratory system) when working in the transportation sector;

IC3.02 - explain the importance of employability skills in achieving success in the workplace.

Prior Knowledge & Skills

· Familiarity with basic electrical circuits from the Grade 9 Science Curriculum

· Awareness of basic hand tool safety

Planning Notes

· Prepare lesson notes, textbook assignments, demonstrations, lab assignments.

· Develop a test in which the students:

· describe how chemical energy is converted into electrical energy inside of a battery, and in turn how electrical energy is converted to produce light, run motors, or operate on-board electronics;

· describe the precautions necessary in working around wet-cell batteries and live electrical circuits, e.g., the need for fusible links;

· read electrical schematics to set up and diagnose electrical circuits;

· use the correct tools to construct an electrical circuit, e.g., soldering tools, wire strippers, diagonal-cutters and crimping tools;

· use the correct tools required to diagnose, test, and repair electrical circuits, e.g., Digital Volt Ohm Meter (D.V.O.M.) to correctly measure the current, voltage, and resistance.

· Invite a guest speaker to speak with the class about the career opportunities in automotive electrical/electronics.

· Arrange for a supply of common automotive insulated wire (assorted gauges), pigtail sockets and accompanying bulbs, various switches, alligator clips, flashers, and a flat, non-conductive piece of material of a suitable size to complete the activity. Access to a 12-volt, wet cell battery is also essential.

· Obtain sample wiring diagrams of a simple lighting system. These wiring diagrams can easily be located in any automotive repair manual/textbook or electronic automotive shop package, or can be created by the teacher.

· Create test harnesses for use when practising with the DVOM. A test harness is made by placing three or four different coloured wires in a sleeve. The harness can simulate specific characteristics which can be identified with a DVOM by installing diodes or resistors on selected wires, or by creating open or short circuits within the tubing. Several test harnesses can be made and labelled. The characteristics of each harness are noted on a master list.

· Cross-curricular opportunities may exist in math and science.

Teaching/Learning Strategies

1. The teacher and students discuss the ever-increasing need to effectively repair wiring systems in modern transportation technology vehicles. Aspects such as career opportunities and post-secondary training required are discussed. If possible, a guest speaker may speak with the class on career opportunities in automotive electrical/electronics.

2. In pairs, students brainstorm and record the maximum number of electrical devices and systems in a modern vehicle. Students check their list against the actual number of systems by referring to a textbook, website (see resources), or an automotive repair manual (or software). The teacher and students then discuss the challenge to the vehicle designer and repair technician of making all components work reliably.

3. The teacher and students discuss and review electrical principles and how electrical circuits work. The key concepts to be reviewed are:

· electrons and electron flow;

· components: power source, a conductor, and a load, fuse;

· characteristics of electron flow (voltage, current, resistance);

· circuit types (parallel, series, series/parallel).

Students take notes on this review.

4. The teacher discusses safety concerns related to the handling of wet-cell batteries. The teacher emphasizes the risk of explosion, the dangers due to exposure to battery acid, and the risks caused by a direct battery short.

5. The teacher explains the operation, service procedures, and rating systems used with automotive batteries. Students participate in a class discussion on the merits of lead/acid batteries and disposal considerations.

6. The teacher discusses the importance of safety when working on any electrical system. Danger such as electrical fires caused by improperly repaired circuits and vehicle damage due to electrostatic discharge must be addressed.

7. In small groups, students are given a power source, i.e., a 12-V automotive type battery or a 12-V DC regulated power supply, several pieces of wire, four identical 12-V light bulbs, and alligator leads. (Note: students must wear safety glasses when working with batteries). The groups are instructed to build two different types of circuits, each capable of lighting two bulbs. They draw simple diagrams to represent their circuits and make qualitative comparison regarding the brightness of the light bulbs. They share their constructed circuits with the class. Students then make notes, record definitions, and give examples of the following: source, load, series circuit, parallel circuit, current, characteristics of schematic drawings, and the meaning of a variety of common schematic symbols.

8. Students locate a simple wiring diagram using shop manuals or computer databases. The basic structure of a wiring diagram and methods of interpreting them are discussed. Students practise reading wiring diagrams by tracing specific circuits on printed copies, using a highlighter or pencil.

9. The teacher and students discuss the proper handling techniques of DVOMs. Through teacher demonstration, students learn how to correctly connect a DVOM (ammeter, voltmeter, and resistance functions) into a circuit and to perform a test to ensure the safety of the equipment prior to taking a measurement.

10. Students use the ammeter to take readings at specific locations in the series and parallel circuits constructed. Students take part in a teacher-led discussion of electrical current and are challenged to explain what it is they have been measuring. They record their readings, the location of their measurements (using schematic drawings and the symbol for ammeter), and their own working definition of electrical current.

11. Students use the voltmeter to take readings across the light bulbs in the series and parallel circuits constructed in Activity 2.1. They record their readings and the location of their measurements (using schematic drawings and the symbol for voltmeter) in their notebooks.

12. Students practise using the DVOM on teacher-prepared sections of wiring harnesses with hidden resistors, diodes, opens, and shorts. Students determine the characteristics of each harness and compare their findings with the master list previously created by the teacher.

13. Each student group creates a circuit with a single resistor (not a light bulb) and a variable voltage supply. Groups use different resistors, e.g., 15, 20, and 30 ohms, and for five different voltages across the resistor, they measure and record the current passing through the resistor. They graph their own results and the results of two other groups that have used different resistors.

14. The teacher demonstrates proper techniques and safety precautions to be followed when making wiring connections including soldering and mechanical connections. (Note: students wear must safety glasses when soldering, and adequate ventilation must be provided.) Students are instructed to avoid breathing fumes and to exercise caution when handling hot soldering irons.

15. Using a wiring diagram, students make a working model of an automobile lighting circuit. The teacher supplies students with common automotive insulated wire, pigtail sockets and accompanying bulbs, a switch, alligator clips, flasher, and a flat, non-conductive piece of material of a suitable size to complete the activity.

16. Students use the DVOM to determine voltage drop, current draw, and resistance across selected sections of the circuit.

Assessment & Evaluation of Student Achievement

· Written quizzes and tests are given at appropriate points of the activity.

· Student-teacher conferencing occurs regularly throughout the activity to check for student understanding (see Appendix A – Student’s Weekly Log Sheet).

· A logbook, completed daily by each student, provides information used to assist the teacher in evaluating individual accomplishments as well as development of learning skills (see Appendix B – Daily Checklist of Student Activities).

· A checklist, completed daily by the teacher, tracks student performance in the shop.

· Notes are checked for completeness and accuracy.

Accommodations

Some program modifications and strategies may include:

· providing pre-printed handouts to summarize board and discussion material, and wiring diagrams;

· providing additional one-on-one time with the teacher or peer tutors;

· providing teacher and peer assistance where appropriate;

· allowing student-to-student discussion and teacher-to-student conferencing throughout the activity;

· providing more complex circuits or complete electrical kit projects for students to work on, for an enrichment activity.

Resources

Chapman, Norm. Principles of Electricity and Electronics for the Automotive Technician. South Puget Sound Community College: Delmar, 2000. ISBN 0-8273-8479-3

Duffy, James E. Auto Electricity and Electronics Technology. Illinois: Goodheart-Wilcox, 1995.
ISBN 1-56637-053-1

Hollembeak, Barry. Automotive Electricity, Electronics and Computer Controls. Technical Training, Inc., Delmar, 1999. ISBN 0-8273-6566-7

Kabala, Thomas. Electricity 1: Devices, Circuits and Materials. Delmar, 2001. ISBN 0-7668-1917-5

Schwaller, Anthony, E. Motor Automotive Technology. Cloud State University: Delmar, 1999.
ISBN 0-8273-8354-1

Thiessen, Frank J. and Davis N. Dales. Automotive Principles and Service, 4th ed. New Jersey: Prentice Hall, 1994. ISBN 0-13-336561-1

OEM Reference and Repair Manuals Available from local Dealerships

Video

Understanding Auto Technology and Repair Video Series – Tape 3: Understanding Automotive Electricity. Delmar, 2000. ISBN 0-7668-0794-0

Understanding Auto Technology and Repair Video Series – Tape 4: How to Diagnose Automotive Electrical Problems. Delmar, 2000. ISBN 0-7668-0795-9

Understanding Auto Technology and Repair Video Series – Tape 5: Understanding Automotive Electronics. Delmar, 2000. ISBN 0-7668-0796-7

Understanding Auto Technology and Repair Video Series – Tape 6: How to Diagnose Automotive Electronics Problems. Delmar, 2000. ISBN 0-7668-0797-5

Websites

How Things Work - http://www.howthingswork.com/

Inner. Auto - http://www.innerauto.com/

Software

Mitchell. On Demand Computerized Service Manuals. San Diego, CA: 1999.

Activity 4.2: Starting System Diagnosis and Service

Time: 600 minutes

Description

Students develop knowledge and skills required for the diagnosis and repair of the starting system electrical circuit and components. Topics covered include starter motor theory of operation, starting circuit components and operation, and system diagnosis and repair procedures. All topics are covered in-class with teacher-directed lessons and demonstrations, and in the lab with student-centred practice and performance tasks.

Students develop thinking and problem-solving skills through the practise of trouble shooting starting system problems using acquired knowledge and skills, and the use of prescribed diagnostic routines and testing procedures.

Strand(s) & Learning Expectations

Strand(s): Theory and Foundation, Skills and Processes, Impact and Consequences

Overall Expectations

TFV.02 - explain the use of each component of a vehicle system;

SPV.01 - function effectively both as individuals and as members of a cooperative team to service
and repair vehicles;

SPV.02 - apply the technological principles of input, process, and output in troubleshooting
vehicle systems;

SPV.03 - use current technology (e.g. on-line information from manufacturers, CD-ROM manuals, computerized diagnostic tools) when servicing, repairing, and modifying vehicles;

ICV.02 - follow safe work practices in the transportation sector workplace, including safety procedures and practices and the use of protective clothing and gear.

Specific Expectations

TF2.01 - analyse and describe the use of each of the following components of a vehicle: the chassis, frame, and body; the engine system; the fuel system; the electrical/ electronics system; the gear and power train system; the steering system; the brake system; and the suspension system;

SP2.01 - use effectively, store safely, and maintain in good working order measurement, hand, power, machine, and pneumatic tools and equipment required for basic service tasks;

SP2.03 - systematically troubleshoot basic service problems on vehicles by organizing the variables into the following categories: input, process, and output;

SP2.04 - access and apply information from manuals, software databases, on-line information and computerized diagnostic tools when troubleshooting and repairing components;

SP3.01 - correctly interpret assembly drawings that depict the components of a vehicle’s systems;

SP4.02 - apply correctly, within the context of transportation technology, the scientific principles related to such areas as properties and states of matter, energy, force, Newton’s laws of motion, simple machines, mechanical advantage, and basic electrical theory;

IC2.01 - work safely when performing tasks in the transportation sector;

IC2.02 - use all required protective clothing and gear (to protect the eyes, ears, hands, head, feet, and respiratory system) when working in the transportation sector.

Prior Knowledge & Skills

· Fundamental understanding of electricity and electromagnetism

· Knowledge of the correct use of test lights and Multi-meters

· Ability to interpret wiring diagrams

· Knowledge of safe work practices when working with electricity

Planning Notes

· Prepare lesson notes, demonstrations, and opportunities to apply learning.

· Develop a test in which students:

· describe electrical energy and explain its conversion to the mechanical operation of solenoids, relays, and motors;

· understand and/or create component and wiring sketches or schematic drawings;

· use current information, technologies, and equipment to diagnose and repair the system;

· describe and demonstrate safe and appropriate work practices.

· Obtain several loose components, e.g., various starter motor and starter drive designs, a ring gear, safety switches, solenoids, and relays to be used as models for students to inspect and handle when discussing theory of operation. (Note: cutaway or disassembled components are helpful in explaining operation.)

· Create an aid for demonstrating the electrical principles of a direct current (DC) motor by winding several metres of light gauge wire around a steel core. The resulting coil can be connected to a variable DC power supply to create an electromagnet. A short loop of wire, connected to the power supply with a small load in series, is held above the coil. The loop moves towards or away from the coil, depending on the polarity of the coil or the loop of wire. Ensure the power supply has overload protection and all circuits have a fusible link.

· Obtain defective components (that have been saved from previous repairs or donated by local repair shops) to be used as examples of malfunctioning circuits on which students can observe the symptoms and testing routines for common faults.

· Create a template for a diagnostic chart and an example of a starting system diagnostic chart from a service manual. A blank template for student use may be made by blocking out some or all of the contents of a printed sample template.

· Provide shop vehicles or actual test/repair work. Shop vehicles may have defective parts installed.

Teaching/Learning Strategies

System Theory and Demonstrations

1. The teacher introduces the activity by discussing the role of the starting system, its parts, and their purpose. The use of display models that students can handle and inspect is desirable.

2. The teacher demonstrates the electrical principle which states, “a current-carrying conductor will move when placed in a magnetic field” by holding a light gauge wire connected to a battery through a small load (test light) over a coil of wire wound around a steel bar. The wire is made to draw towards or lift away from the coil by reversing the polarity of the wire. The teacher reviews the following key concepts:

· construction of starter motors and the electrical theory of operation for automotive DC motors;

· construction and operation of inertia drives and over-running clutch drives, including the concept of gear ratio;

· construction and operation of relays and solenoids;

· schematic layout of circuit including ignition switch and park/neutral or clutch switch.

3. The teacher demonstrates, working components by mounting the starter motor, relay, or solenoid securely in a bench vice and connecting it to a shop battery with booster cables or other heavy gauge conductors. The use of a remote starter switch demonstrates the use of this device as well as provides a safe way to operate the starter or other components. A test light or ohm meter is used to demonstrate the results of the relay operation. (Note: the teacher and students must wear safety glasses when handling batteries and operating components in this manner.)

System Testing and Diagnosis

4. The teacher reviews electrical safety with students, with a special emphasis on fusing circuits and the hazards of wet cell automotive style batteries.

5. Students are supplied with a typical wiring diagram for a starting system in a common vehicle. Students trace the system circuit using a pen for high current conductors and a pencil for low current conductors. The teacher completes the same activity using an overhead slide and projector, and coloured markers. Students check their work against the overhead.

6. The teacher notes possible system faults on the diagram, such as a discharged battery or open circuit in the solenoid. Students suggest effects on the system in terms of what they expect, hear, or see with test light or volt meter. As each fault is discussed, a system model with defective components or connections is used to verify the findings of students. The teacher uses this opportunity to demonstrate any alternative or better way of testing for each fault, including performing starter draw and voltage drop tests. Students record their observations.

7. Students create a diagnostic chart from their recorded observations. A template may be made by “deleting” some or all of the contents of a diagnostic chart provided by the teacher. Once complete, the chart is compared to a similar chart taken from a service manual. Students update their charts with any necessary changes.

System Service

8. Working with a partner, students assess the condition of a sample starting circuit. Starter draw tests are performed with teacher assistance and compared to specifications, as is engine cranking speed.

9. If starting system problems are observed, students locate and use the appropriate trouble chart and determine the course of action.

10. After the correct repair procedures have been located and the teacher has been consulted, the students perform the required repair work.

Assessment & Evaluation of Student Achievement

· Log books are completed daily by students, providing students an opportunity to demonstrate knowledge acquired and note daily participation and achievements (see Appendix A – Student’s Weekly Log Sheet).

· Text and teacher-developed assignments, notes, and diagnostic charts are collected and evaluated for neatness and correctness.

· A test is given to determine student learning.

· A daily checklist of student activities is completed by the teacher, and tracks student performance in the shop ( see Appendix B – Daily Checklist of Student Activities).

Accommodations

Some program modifications and strategies may include:

· reviewing students’ IEPs and making the necessary accommodations;

· providing enlarged wiring diagrams or a magnifying glass to accurately trace circuits;

· providing teacher and peer assistance where appropriate;

· allowing for adjusted timelines for the completion of the circuit activities;

· providing additional one-on-one time with the teacher or peer tutors;

· allowing student-to-student discussion and teacher-to-student conferencing throughout the activity;

· having peer tutors assist in the handling of equipment;

· encouraging students to research why some starting motors/systems draw much more electrical energy (current) than others when starting, for an enrichment activity.

Resources

Chapman, Norm. Principles of Electricity and Electronics for the Automotive Technician. South Puget Sound Community College: Delmar, 2000. ISBN 0-8273-8479-3

Duffy, James E. Auto Electricity and Electronics Technology. Illinois: Goodheart-Wilcox, 1995.
ISBN 1-56637-053-1

Hollembeak, Barry. Automotive Electricity, Electronics and Computer Controls. Technical Training, Inc., Delmar, 1999. ISBN 0-8273-6566-7

Schwaller, Anthony, E. Motor Automotive Technology. Cloud State University: Delmar, 1999.
ISBN 0-8273-8354-1

Thiessen, Frank J. and Davis N. Dales. Automotive Principles and Service, 4th ed. New Jersey: Prentice Hall, 1994. ISBN 0-13-336561-1

Video

Understanding Auto Technology and Repair Video Series – Tape 3: Understanding Automotive Electricity. Delmar, 2000. ISBN 0-7668-0794-0

Understanding Auto Technology and Repair Video Series – Tape 4: How to Diagnose Automotive Electrical Problems. Delmar, 2000. ISBN 0-7668-0795-9

Understanding Auto Technology and Repair Video Series – Tape 5: Understanding Automotive Electronics. Delmar, 2000. ISBN 0-7668-0796-7

Understanding Auto Technology and Repair Video Series – Tape 6: How to Diagnose Automotive Electronics Problems. Delmar, 2000. ISBN 0-7668-0797-5

Activity 4.3: Charging System Diagnosis and Service

Time: 600 minutes

Description

This activity builds upon the previous two activities by requiring students to use skills and knowledge acquired in those activities to understand charging system theory of operation and perform diagnostics and repairs. Students develop knowledge and skills required to diagnose and repair the charging system electrical circuits and components. All topics are covered in-class with teacher-directed lessons and demonstrations, and in the lab with student-centred practise and performance tasks.

Students develop thinking and problem-solving skills through the practise of trouble-shooting charging system problems using acquired knowledge and skills, as well as using prescribed diagnostic routines and testing procedures.

Strand(s) & Learning Expectations

Stand(s): Theory and Foundation, Skills and Processes, Impact and Consequences

Overall Expectations

TFV.02 - explain the use of each component of a vehicle system;

TFV.03 - analyse and describe the interrelationships of vehicle systems;

SPV.01 - function effectively both as individuals and as members of a cooperative team to service and repair vehicles;

SPV.02 - apply the technological principles of input, process, and output in troubleshooting
vehicle systems;

SPV.03 - use current technology (e.g., on-line information from manufacturers, CD-ROM manuals, computerized diagnostic tools) when servicing, repairing, and modifying vehicles;

ICV.02 - follow safe work practices in the transportation sector workplace, including safety procedures and practices and the use of protective clothing and gear.

Specific Expectations

SP1.04 - develop a plan of procedures that indicates the steps required when repairing or
servicing a vehicle;

SP1.05 - complete a work order for a specific transportation technology task;

SP2.01 - use effectively, store safely, and maintain in good working order measurement, hand, power, machine, and pneumatic tools and equipment required for basic service tasks;

SP2.03 - systematically troubleshoot basic service problems on vehicles by organizing the variables into the following categories: input, process, and output;

SP2.04 - access and apply information from manuals, software databases, on-line information, and computerized diagnostic tools when troubleshooting and repairing components;

SP3.01 - correctly interpret assembly drawings that depict the components of a vehicle’s systems;

SP4.03 - use appropriate technical language in technical reports and presentations;

IC2.01 - work safely when performing tasks in the transportation sector;

IC2.02 - use all required protective clothing and gear (e.g., to protect the eyes, ears, hands, head, feet, and respiratory system) when working in the transportation sector.

Prior Knowledge & Skills

· Fundamental understanding of electricity and electrical circuits

· Ability to use test lights and multi-meters correctly

· Ability to interpret wiring diagrams properly

· Awareness of some of the concerns regarding electrical safety

Planning Notes

· Prepare lesson notes, demonstrations, and opportunities to apply learning.

· Develop a test in which students:

· describe how an alternator converts mechanical energy into electrical energy;

· describe the basic types of alternators and how they are constructed;

· read electrical schematics consisting of alternator control devices, charging indicator, and a battery;

· diagnose and repair alternators and regulators (external and internal) using proper test equipment;

· describe the advantages of an alternator over a generator;

· describe and practise safe and appropriate work habits.

· Obtain several styles of alternators and regulators (including cutaway and disassembled components) for students to inspect during discussions to help them to understand the theory and principles of operation.

· Set up shop vehicles with defective parts installed, ready for diagnosing.

· Set up defective parts for bench tests, including internal circuitry checks.

· Obtain charging system diagnostic charts from class shop manuals or from area dealerships.

· Create a simple demonstration aid by winding a length of small gauge wire and attaching each end to a sensitive DVOM. As a magnetic field is passed over this winding, an induced voltage and current can be read on the meter.

Teaching/Learning Strategies

System Theory and Demonstrations

1. The teacher introduces the activity by discussing the role of the charging system, its parts, and their purpose. Students inspect display models to increase understanding.

2. The teacher discusses how charging systems work on the principles of magnetism to change mechanical energy into electrical energy using induction. The key points to include are:

· fundamentals such as electromagnetic induction principles, speed and voltage induction,

· factors affecting voltage and amperage output, construction of alternators (external and internal regulators), and theory of operation;

· schematic layout, including different styles of charging indicators and lights;

· advantages of an alternator over a DC generator (e.g. limited current output and poor low speed characteristics).

3. The teacher performs demonstrations on a vehicle using an inductive pickup and a multi-meter to show amperage and voltage output with varying loads.

System Testing and Diagnosis

4. The teacher starts the activity by having students reflect upon previous experiences with charging system failures.

5. The teacher supplies the students with a typical charging system schematic and (using an overhead slide) follows through circuit operation and relates it to actual on-car set-up and design.

6. The teacher adds open or shorted circuits to the schematic and students respond with the effects that they would have on operation. Students must indicate where power and ground is found in the circuit. On the schematic diagram, the teacher indicates simple test points for input and output voltage checks.

7. Students use service manuals to locate correct test procedures and diagnose shop vehicles with inoperative charging systems.

System Service

8. Students test operational charging systems for proper voltage and current output with varying loads. (Note: students must use proper tools and equipment, and all safety precautions must be followed.)

9. Students disassemble alternators at the bench and check slip rings, brushes, and bearings for wear. Internal parts such as the stator, rotor, rectifier assembly, and regulator (where applicable) are tested. Any defective components are discussed with the teacher.

Assessment & Evaluation of Student Achievement

· Log books are completed daily by students providing students an opportunity to demonstrate knowledge acquired and note daily participation and achievements (see Appendix A – Student’s Weekly Log Sheet).

· Assignments, notes, and diagnostic charts are collected and assessed for neatness and correctness.

· A test is given to determine student learning.

· A daily checklist of student activities is completed by the teacher, and tracks student performance in the shop (see Appendix B – Daily Checklist of Student Activities).

Accommodations

Some program modifications and strategies may include:

· reviewing students’ IEPs and making the necessary accommodations;

· providing enlarged wiring diagrams or a magnifying glass to accurately trace circuits;

· providing teacher and peer assistance where appropriate;

· providing additional one-on-one time with the teacher or peer tutors;

· having peer tutors assist in the handling of equipment;

· allowing for adjusted timelines for the completion of the this activity;

· allowing for additional time after class to continue the study of the operation of the charging system.

Resources

Chapman, Norm. Principles of Electricity and Electronics for the Automotive Technician. South Puget Sound Community College: Delmar, 2000. ISBN 0-8273-8479-3

Derato, Frank C. Automotive Electrical and Electronics Systems 2nd ed. United States: Glencoe Division Macmillian/McGraw-Hill, 1994. ISBN 0-02-800412-4

Erjavec, Jack. Automotive Technology: A Systems Approach, 3rd ed. United States: Delmar Thomas Learning, 2000. ISBN 0-7668-0673-1

Hollembeak, Barry. Automotive Electricity, Electronics and Computer Controls. Technical Training, Inc., Delmar, 1999. ISBN 0-8273-6566-7

Schwaller, Anthony, E. Motor Automotive Technology. Cloud State University: Delmar, 1999.
ISBN 0-8273-8354-1

Thiessen, Frank J. and Davis N. Dales. Automotive Principles and Service, 4th ed. New Jersey: Prentice Hall, 1994. ISBN 0-13-336561-1

Video

Understanding Auto Technology and Repair Video Series – Tape 3: Understanding Automotive Electricity. Delmar, 2000. ISBN 0-7668-0794-0

Understanding Auto Technology and Repair Video Series – Tape 4: How to Diagnose Automotive Electrical Problems. Delmar, 2000. ISBN 0-7668-0795-9

Understanding Auto Technology and Repair Video Series – Tape 5: Understanding Automotive Electronics. Delmar, 2000. ISBN 0-7668-0796-7

Understanding Auto Technology and Repair Video Series – Tape 6: How to Diagnose Automotive Electronics Problems. Delmar, 2000. ISBN 0-7668-0797-5

Websites

Learn How Everything Works – http://www.howthingswork.com/

Appendix A

Student’s Weekly Log Sheet

This page is to be completed daily, detailing the activities with which you have been involved. Your entries are used as an aid in determining a Practical Performance mark. Include any information you would like your teacher to know when calculating this mark. This page must be handed in each week.

Name: _________________ Class: ____________ (Monday) Date: ________