Inspect and Test Fusible Links, Circuit Breakers, Relays, Solenoids, and Fuses; Replace

Inspect and test fusible links, circuit breakers, relays, solenoids, and fuses; replace as needed. Lesson Plan for DIT 190-191 ELECTRICAL/ELECTRONIC SYSTEMS Course HS Title: Electrical/Electronic Systems Program: KCTCS Courses included in HS Title: (Lesson is prepared for course highlighted.) KCTCS Course No. KCTCS Course Title DIT 190 Electrical/Electronic Systems

Introduction/Conte This lesson will instruct the student on how to inspect and test fusible links, xt circuit breakers, relays, solenoids, and fuses, and replace as needed. Knowledge of these techniques and the skills required to correct problems associated with this task are necessary for a student to acquire if they wish to compete for high paying, high skilled jobs in a Diesel Repair Facility. Entry level technicians need to be able to perform this task to 100% accuracy. Incorrectly performing this task can lead to an automobile accident or create customer satisfaction issues. Prepared By School Date:

Lesson Grade Level No. Students No.IEP's: Length:

Task Inspect and test fusible links, circuit breakers, relays, solenoids, and fuses; replace as needed.

Objective Given the proper tools and instruction, the student will be able to inspect and test fusible links, circuit breakers, relays, solenoids, and fuses, replace as needed, and pass a written test covering the task with 100% accuracy.

Connections: Skills Standards: OH 001 OH 002 OH 003 OD 002 OD 003 OD 005 New Common Core Standards: RST 11-12 3 N-Q.1 Common Core Technical Standards: TD-OPS 2 TD-SYS 2 New Generation Science Standards: HS-PS2-5. HS-PS3-3. HS-PS3-5.

INSTRUCTIONAL MATERIALS/TECHNOLOGY

Teacher Designed Materials and Other Handouts

Textbooks and Workbooks Author Title/ISBN No. Edition Publisher Pages James D Automotive technology second Prentice 303-307 Halderman Hall

Equipment Quantity Item Source

Content/Presentation/Demonstration Outline Describe to students the purpose and operational characteristics of a fusible link, circuit breaker and fuse.

Fusible link: a fusible link is a type of fuse that consists of a short length of standard copper-strand wire covered with a special nonflammable insulation. This wire is usually four wires smaller than the wire of the circuits it protects. The special thick insulation over the wire may make it look larger than other wires of the same gauge number. If excessive current flow (caused by a short to ground or a defective component) occurs, the fusible link will melt in half and open the circuit to prevent a fire hazard. Some fusible links are identified with “fusible link” tags at the junction between the fusible link and the standard chassis wiring, which represent only the junction. Fusible links are the backup system for circuit protection. All current except the current used by the starter motor flows through fusible links and then through individual circuit fuses. It is possible that a fusible link will melt and not blow a fuse. Fusible links are installed as close to the battery as possible so that they can protect the wiring and circuits coming directly from the battery. Circuit breakers: circuit breakers are used to prevent harmful overload (excessive current flow) in a circuit by opening the circuit and stopping the current flow to prevent overheating and possible fire caused by hot wires or electrical components. Circuit breakers are mechanical units made of two different metals (bimetallic) that deform when heated and open a set of contact points that work in the same manner as an “off” switch. Circuit breakers, therefore, are reset when the current stops flowing, which causes the bimetallic strip to cool and the circuit to close again. A circuit breaker is used in circuits that could affect the safety of passengers if a conventional non- resetting fuse were used. The headlight circuit is an excellent example of the use of a circuit breaker rather than a fuse. A short or grounded circuit anywhere in the headlight circuit could cause excessive current flow and, therefore, the opening of the circuit. A sudden loss of headlights at night could have disastrous results. A circuit breaker opens and closes the circuit rapidly, herby protecting the circuit from overheating and also providing sufficient current flow to maintain at least partial headlight operation. Circuit breakers are also used in other circuits where conventional fuses could not provide for the surges of high current commonly found in those circuits. Examples are the circuits for the following accessories: power seats, power door locks, and power windows. Fuses: fuse should be used in every circuit to protect the wiring from overheating and damage caused by excessive current flow as a result of a short circuit or other malfunction. The symbol for a fuse is a wavy line between two points. A fuse is constructed of a fine tin conductor inside a glass, plastic or ceramic housing. The tin is designed to melt and open the circuit if excessive current flows through the fuse. Each fuse is rated according to its maximum current carrying capacity. Many fuses are used to protect more than one circuit of the automobile. A typical example is the fuse for the cigarette lighter that also protects many other circuits such as those for the courtesy lights, clock, and other circuits. A fault in one of these circuits can cause this fuse to melt, which will prevent the operation of all other circuits that are protected by the fuse. Instruct students that a relay is an electromagnetic switch with a movable arm. Relays allow a small current to control a larger current in the case of a starter relay. Instruct students that relays can be visually inspected for broken terminals or corrosion but should be tested with current flowing through. Inform student that they can place the relay in a similar circuit (horn, wiper, and starter) then operate the circuit to see if the relay is functioning. Instruct students that solenoids can be tested in the same manner. Solid-state devices are those devices typically made up of electronic components like diodes or transistors. Solid-state devices can be visually inspected but typically have to be placed in the circuit and tested live.

Applications/Practice 1 Refer to content

Evaluation and feedback Prior to Testing or Lab Work Objective 1. / Formative assessment / Instructor will observe students as they practice the procedure to assure correct procedure and safety practices are being followed. A checklist will be utilized to chart student progress on the task. Questioning techniques will be utilized as necessary to demonstrate student comprehension / Adaptations and/or accommodations for special needs students will be added if required.

STUDENT ASSESSMENT: (Assess student progress with performance criteria.) Objective 1 / Summative assessment / written test questions on stated objective / adaptation and / or 1 accommodations for special needs students will be added if required

IMPACT--Reflection/Analysis of Teaching and Learning: (How did students’ progress in relation to the state objectives? Was the instruction successful? Analyze samples of student work particularly that which is unsatisfactory, for the purpose of planning further instruction.)

REFINEMENT--Lesson Extension and Follow-up: (To be filled in as the lesson is modified during initial planning and/or during the teaching learning process.)