AURETR112 Student Assessment - Theory

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Course Code AUR30620 Course Name Certificate III in Light Vehicle Mechanical Technology Unit Code AURETR112 Unit Name Test and repair basic electrical circuits Due Date Assessment Name Automotive Portfolio Part A: Short answer questions Student No . ________________ Student Name Rommel Garcia Student Phone 0410725047 Student Email rommelgarcia07@hotmail.com Student Declaration I declare that this assessment is my own work and where my work is supported by documents from my workplace placement/employer permission has been granted. Note: Filling out this coversheet as part of an electronic submission and approving the above information will operate in the same way as physically signing this cover sheet. Student name or signature: Rommel Garcia Office Use Only Date/s Received: ___/___/___ ___/___/___ ___/___/___ Date/s Assessed: ___/___/___ ___/___/___ ___/___/___ Result of Assessment: ___________ ___________ ___________ Entered on Training Plan Moderation Signature Note for Assessors: Filling out the above Office Use Only section as part of an electronic submission will operate in the same way as physically signing this cover sheet. If not physically signed, Assessor must print their name in signature box /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx Imagine Education Student Assessment Cover Sheet

Course Code and Name: AUR30620 Certificate III in Light Vehicle Mechanical Technology Unit Code: AURETR112 Unit Title: Test and repair basic electrical circuits For this assessment you are required to answer all of the questions. You are permitted to research the answers by reading the learner guide, text books, theory notes and accessing the internet. If more room is needed label each task with the question number and use headings or dot points to make your work clear for your trainer and assessor. Please follow the Referencing Guide contained on your Course handbook. Please attach a student assessment cover sheet to each unit submission. You must complete the cover sheet in full detail. 1. Where can you find the information required in the table below? Item Location Three (3) examples Content Three (3) examples Workplace procedures related to a test and repair basic electrical circuits  https://training.gov.au/ Training/Details/auretr2 012  Automotive Mechanics 10th Edition  Workshop manual  Procedures  Guidelines  Safety Manufacturer specifications related to a test and repair basic electrical circuits  Owner's manual  manufacture's website  repair manual  Ems systems  Data testing  Ems voltage specification 2. Where can you find the information provided by the customer or your supervisor that you will need to test and repair basic electrical circuits? Give three (3) examples.  Owners manual  Car maintenance and servicing checklists  Finding electrical faults 3. List three (3) methods you can use to locate the required information to test and repair basic electrical circuits.  Repair manual  Ems data  Manufacturer specification 4. With regards to testing and repairing basic electrical circuits: a) List the three (3) main circuit types. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx Imagine Education Assessment Questions Part A

b) List the two (2) types of circuit connections. c) What is a circuit diagram and what are the two (2) different types? d) What are circuit symbols? e) List three (3) examples of where you can find the information you need to test and repair a circuit. A) 1. Close Cirucit 2. Open Circuit 3. Short Circuit B) 1. Parallel Circuit 2. Series Circuit C) A circuit diagram also called an electrical diagram, elementary diagram or electronic schematic is a simplified graphical representation of an electrical circuit. Types 1. Schematic style circuit diagram 2. Pictorial style circuit program D) Circuit symbols are used in circuit diagrams showing how a circuit is connected together. The actual layout of the components is usually quite different from the circuit diagram. E) 1. Owners manual 2. Car maintenance and servicing checklists 3. Finding electrical faults /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

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5. Explain the workplace procedures in the table below required to develop and carry out a test and repair a basic electrical circuits. Establish serviceability of tools and equipment. A person conducting a business or undertaking (PCBU) who carries out electrical work must ensure the electrical safety of all persons and property likely to be affected by the electrical work. A PCBU must have procedures in place to ensure that tools, testing equipment and personal protective equipment are regularly inspected and tested. This requirement ensures that workers carrying out the work are electrically safe and that the work, when completed, is electrically safe. Documentation procedures Record keeping documents what you’re doing to maintain and improve your working environment and health and safety. Keeping records can help you track your business' health and safety performance, as well as satisfy the legal requirements. The following records must be kept:  Working policies and procedure  Induction  Safety procedures  All incident/hazard reports  Hazardous chemicals and asbestos registers (if those substances are in your workplace)  Plant registration documents  Tests, maintenance, inspection, and repairs for specific items of plant. It's also useful to keep records of:  The method of recognising risks, risk management, and monitoring  Maintenance of all items of plant and equipment  Workers' induction and training. 6. Describe the housekeeping procedures required when developing and carrying out a test and repair basic electrical circuits from the items listed in the table below. Examination of tools and equipment. All tools, testing equipment, and PPE must be visually inspected before each use for signs of damage. PCBUs should have 'pre-start' visual inspection procedures in place to make sure that equipment such as PPE, tools, rubber mats, and LV rescue kits are in proper working order before use. Testing equipment must be checked for damage to insulated leads and probes and needs to be confirmed as in working order before use. Testing equipment needs to be tested regularly to make sure it provides the level of protection required. Testing intervals will depend on several /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

factors, including:  the frequency of use  manufacturer’s advice  the environment in which it is being used Storage of equipment procedures  Place your tools in a dry place. It seems obvious, but garages and basements and other enclosed spaces, particularly if they are not heated or air-conditioned, may have problems with humidity. If you keep your tools in such a location, particularly if you keep them out on shelves or pegboards, consider investing in a dehumidifier to maintain the level of dampness down. They are not expensive, especially compared to your investment in your equipment, and most of them let you set a level of humidity, so the dehumidifier only turns on when it needs to.  Store the power tools in their original cases. When you have a climate-controlled space, the hard-plastic cases they come with are your best choice for storing power tools. They are not only kept free from humidity but are also well covered.  Use rust collector or silica gel packets. Packs of silica gel that come with tonnes of packaging are perfect for keeping moisture at bay. Put them into drawers or toolboxes, and they can help keep away the rust. For the same reason, you can also purchase rust inhibitors and even anti-rust liners for drawers and shelves. Identification, tagging and isolation of faulty equipment procedures. Check all tools or equipment if there's any damage or faults and if you found out that it's not safe to use attach tags to indicate that the tools is not in good condition to use. Safe disposal of excess material procedures  Keep lids on your bins or store them in a covered zone to prevent the wind from blowing waste away  Avoid storing waste bins on footpaths or property that belongs to others  Separate different kinds of waste for easier collection and recycling.  Use a liquid waste contractor to dispose of spent chemicals and other liquid waste. Do not put liquid wastes, such as oily rags or filters, into your waste bins Recycling procedures Electric cables recycling Copper aluminium wires, industrial cabling, and automotive cabling harness are valuable resources inside them for the recovery of conductive metals, especially copper and aluminium. Recycling of copper cables  Armoured cables larger than 100 mm in diameter  Tech cables of any size. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

 Underwater cables are containing fat and oil.  Very thin wires (phone cables, data cables, machine recycling cables), electrical and electronic equipment (WEEE) cables, capillary cables.  Cables obtained from the demolition of vehicles contaminated with oily or sticky materials 7. List three (3) workplace health and safety requirements for each of the items in the table below associated with testing and repairing of basic electrical circuits. Using specialised tools and equipment Make it sure that the tools or equipment are in good condition before using it. The one who's going to use it should have a knowledge or training about the use of the tool or equipment. Using appropriate personal protective equipment (PPE) Wearing a PPE is required when working in a workshop to prevent any injury or accidents. 8. Identify the hazards and risks associated with wearing jewellery while working around electrical systems. Hazards List two (2) Risks List four (4) Hazards and controlling risks associated with wearing jewellery while working around electrical systems Electrical shock Fire -it cause severe burnt -contact with exposed live parts causing electric shock and burns (for example exposed leads or other electrical equipment coming into contact with metal surfaces such as metal) -sparks -explosion 9. Identify the environmental procedures related to testing and repairing basic electrical circuits. List three (3).  The waste materials must be store in a proper bin.  Sort all the electrical waste if it's need to recycle or dispose it.  Always work in ventilated area when working with electric. 10. Describe the basic theory and principle of the automotive electrical systems listed in the table below. Alternating Current (AC) Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Direct current (DC) Direct current (DC) is an electric current that is uni-directional, so /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

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the flow of charge is always in the same direction.[2] As opposed to alternating current, the direction and amperage of direct currents do not change. It is used in many household electronics and in all devices that use batteries.[3] Voltage Voltage is the pressure from an electrical circuit's power source that pushes charged electrons (current) through a conducting loop. Resistance Resistance is a measure of the opposition to current flow in an electrical circuit. Resistance is measured in ohms, symbolized by the Greek letter omega (Ω). Ohms are named after Georg Simon Ohm (1784-1854), a German physicist who studied the relationship between voltage, current and resistance. Power Electric power is the rate at which electrical energy is transferred by an electric circuit. Ohm’s law Ohm's law states that the voltage across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperatures remain constant. In the equation, the constant of proportionality, R, is called Resistance and has units of ohms, with the symbol Ω. 11. Identify and describe the operation of the electrical circuits listed in the table below. Series circuit Components connected in series are connected along a single "electrical path", and each component has the same current through it, equal to the current through the network. The voltage across the network is equal to the sum of the voltages across each component. Parallel circuit Components connected in parallel are connected along multiple paths, and each component has the same voltage across it, equal to the voltage across the network. The current through the network is equal to the sum of the currents through each component. Series parallel circuits A series-parallel circuit, or combination circuit, combines both series and parallel connections. ▪ Most electronic circuits fall into this category. Series-parallel circuits are typically used when different voltage and current values are required from the same voltage source. 12. Describe the key features of the basic electrical circuit components, listed in the table below. Cable types Various types of cables are used everywhere for various applications. Not all cables perform the same application. The function of a cable depends upon the type of cable. The electrical cables are made of aluminium or copper wires protected by an insulating coating which can be made of synthetic polymers. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

Automotive wire is available in two main materials: copper or aluminum. Copper is more conductive, flexible, and less likely to corrode than aluminum; however copper weighs more and is prone to price fluctuations, so you'll need a good distributor to keep your costs low. Cable sizes Cross sectional area of the conductor – sometimes called ‘cable size’ Given as mm², it describes the total cross-sectional area of the copper conductor. Cable will be sized 1 mm², 2 mm², 4 mm² etc. and may be written as 1 mm, 2mm, 4mm. This is not the diameter of the cable. Current carrying capacity. Current-carrying capacity, cables with a nominal voltage up to 1000 V and heat resistant cables VDE 0298-4 06/13 table 11, column 2 and 5. Circuit protection devices A circuit protection device is a current or voltage, sensitive device that protects a circuit from either overcurrent, or overvoltage, conditions. Fuses Unlimited offers a broad range of circuit protection devices. Switches a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. Relays The term Relay generally refers to a device that provides an electrical connection between two or more points in response to the application of a control signal. The most common and widely used type of electrical relay is the electromechanical relay or EMR. Automotive globes Mechanically, light bulbs consist of a metal base, which itself consists of a screw thread contact (attached electrically to one side of the filament), insulating material and an electrical "foot" contact (the little brass bulge on the bottom which is electrically connected to the other end of the filament.) The metal contacts at the base of the bulb are connected to two stiff wires that go to the center of the bulb and, in turn, hold the filament. The bulb itself is the glass housing that not only shields the filament from oxygen in the atmosphere but also holds in an inert gas, usually argon. More about that later. The filament is the part of the bulb that does the work to create light. It is made up of a long, extremely thin (about .01 inch) length of tungsten, a very versatile metal. The typical filament in a household bulb is over six feet long and is tightly wound to form a double-coil. 13. Describe the procedures for using and operating the electrical test equipment, listed in the table below. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

Digital multimeters A digital multimeter is a test tool used to measure two or more electrical values—principally voltage (volts), current (amps) and resistance (ohms). It is a standard diagnostic tool for technicians in the electrical/electronic industries. Test lights suitable for circuit testing, including resistive and light emitting diode (LED) 1. Use a digital multimeter that can take diode readings. Basic multimeters measure just amps, volts, and ohms. To test LED lights you will need a multimeter with a diode setting. 2. Hook up the red and black test leads. The red and black test leads should be connected to the outlets on the front of the multimeter. The red lead is the positive charge. The black lead is the negative and should be plugged into the input labelled "COM." 3. Turn the multimeter dial to the diode setting. Turn the dial on the front of your multimeter clockwise to move it away from the "off" position. Keep turning it until you land on the diode setting. If it is not labelled explicitly, the diode setting may be represented by the diode circuit symbol.  The diode symbol visually represents both its terminals, the cathode and the anode. 4. Connect the black probe to the cathode and the red probe to the anode. Touch the black probe to the cathode end of the LED, which is usually the shorter prong. Next, touch the red probe to the anode, which should be the longer prong. Be sure to connect the black probe before the red probe, as the reverse might not give you an accurate reading.  Make sure that the cathode and anode are not touching each other during this test, which may prevent the current from passing through the LED light and hinder your results.  The black and red probes should also not be touching each other during the test.  Making the connections should cause the LED to light up. 5. Check the value on the multimeter's digital display. When the probes are touching the cathode and anode, an undamaged Led light should display a voltage of approximately 1600 mV. If no reading appears on your screen during the test, start again to make sure the connections were made properly. If you have performed the test properly, this may be a sign that the LED light is not working.  If your supply does not provide any output voltage, then the transformer needs to be replaced.  If you have voltage on the output then LED lights are not working and need to be replaced. Evaluate the brightness of the LED. When you make the proper connections to test your LED, it should light up. After noting the reading on the digital screen, look at the LED itself. If it has a /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

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normal reading but looks dim, it is likely a low-quality LED. If it shines brightly, it is probably a high-efficiency LED light. Test probes suitable for testing circuit continuity How to Test for Continuity with a Digital Multimeter 1. Turn the dial to Continuity Test mode. It will likely share a spot on the dial with one or more functions, usually resistance (Ω). With the test probes separated, the multimeter’s display may show OL and Ω. 2. If required, press the continuity button. 3. First insert the black test lead into the COM jack. 4. Then insert the red lead into the VΩ jack. When finished, remove the leads in reverse order: red first, then black. 5. With the circuit de-energized, connect the test leads across the component being tested. The position of the test leads is arbitrary. Note that the component may need to be isolated from other components in the circuit. 6. The digital multimeter (DMM) beeps if a complete path (continuity) is detected. If the circuit is open (the switch is in the OFF position), the DMM will not beep. 7. When finished, turn the multimeter OFF to preserve battery life. Continuity testing overview  Continuity is the presence of a complete path for current flow. A circuit is complete when its switch is closed.  A digital multimeter’s Continuity Test mode can be used to test switches, fuses, electrical connections, conductors and other components. A good fuse, for example, should have continuity.  A DMM emits an audible response (a beep) when it detects a complete path.  The beep, an audible indicator, permits technicians to focus on testing procedures without looking at the multimeter display.  When testing for continuity, a multimeter beeps based on the resistance of the component being tested. That resistance is determined by the range setting of the multimeter. Examples: If the range is set to 400.0 Ω, a multimeter typically beeps if the component has a resistance of 40 Ω or less. If the range is set 4.000 kΩ, a multimeter typically beeps if the component has a resistance of 200 Ω or less.  The lowest range setting should be used when testing circuit components that should have low-resistance value such as electrical connections or switch contacts. Fused test lead Fused test leads feature a built-in fuse within the test probe that provides an additional layer of protection to the individual undertaking an electrical measurement. Fused test leads can protect the technician against hazards from where electrical supply is short-circuited. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

14. Describe and explain the types of common faults listed in the table below. Open circuit An open-circuit fault occurs if a circuit is interrupted by a failure of a current-carrying wire (phase or neutral) or a blown fuse or circuit breaker. In three-phase systems, a fault may involve one or more phases and ground, or may occur only between phases. High resistance circuits A high-resistance connection (HRC) is a hazard that results from loose or poor connections in traditional electrical accessories and switchgear which can cause heat to develop, capable of starting a fire. Short circuits Short circuit faults are also called as shunt faults. These faults are caused due to the insulation failure between phase conductors or between earth and phase conductors or both. Damaged insulation Electrical insulation failure occurs when the insulation in the motor begins to degrade over time or for other reasons. Aging or overheating causes chemical changes in the insulation that cause the insulation to become more conductive and become less effective at preventing the current from following undesirable paths either between the conductors or to the motor’s frame. Some insulation failures particularly in the ground wall insulation system are instantaneous due to moisture ingression, contamination, or other unusual unique events. These events attack voids or other weaknesses in the insulation and lead to premature failure. Faults in the winding insulation system materialize slowly and deteriorate over time. Common causes of insulation failure include:  Overheating  Winding contamination  Excessive current draw  Poor power quality  Harmonic distortion Frayed wiring A frayed wire is a wire whose ends have been severed or exposed through its insulation. Frayed wires are at risk of lower performance and can even be dangerous if left in disrepair. Burnt wiring Loose Connections When electrical connections are installed incorrectly of they are not connected properly then heat can accumulate. Conductors and wires will heat up where the insulation of the wire can begin to melt. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

Water and moisture ingress Water ingress in cars is when water finds its way into your car’s interior. What causes water ingress in cars? If you have found water in your car, it’s likely to have been caused by:  Weak/broken seams or gaskets on a vehicle’s roof  Blocked sunroof drain holes on a vehicle’s roof  Loose/broken windscreen gaskets on a vehicle  Clogged AC evaporator drain  Heater core leak Connector damage Dead Battery A dead battery is the most common and obvious electrical problem. When you turn the key the car's engine won't turn over. You may still be able to use your lights and other accessories. This can usually be resolved with a jump start. Battery Will Not Charge However, a battery that will no longer hold a charge will need to be replaced. Batteries do wear out after many years of use. Bad Alternator A damaged or otherwise malfunctioning alternator could also prevent the battery from recharging. If your car begins to lose electrical function, such as dim headlights, as you drive, you can bet on alternator trouble. Fatigued Starter or Solenoid If the starter or solenoid goes out your car's engine won't turn over. More than likely you'll hear a loud click or series of clicks if the starter has gone bad. Bad Battery Cables A corroded loose battery cable could be the root of a no start situation. Check the connections if your car won't start. Blown Electrical Fuses A blown fuse is a quick and easy fix, if it's the culprit of your trouble. Failed Spark Plugs Loose or dirty plugs will affect the operation of your car. Terminal damage 1. Poor contact : The metal conductor inside the terminal is the core part of the terminal, which transmits power, signals, etc. to other parts in contact with it. The metal conductor inside the terminal must have good conductivity. If the contact design is /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

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unreasonable, the material is selected incorrectly, the size is substandard, or the plating layer is handled improperly, it will cause poor contact of the terminal. Many low-priced terminal blocks on the market often have metal conductors or poor materials. In the event of a failure, the minor ones may just cause damage to the product, and the more serious ones are more likely to cause major accidents such as burning. 2. Poor fixation : The wiring terminal needs to be fixed in a certain position to achieve a stable connection. Sometimes careless installation is imperfect, or product durability is limited, such as too many plugs and unplugs, resulting in poor fixation, lighter ones affect reliable contact and cause instantaneous power failure, and more serious product disintegration. Disassembly refers to the abnormal separation between the plug and the socket, the pin and the socket caused by the unreliable structure of the terminal in the plug-in state due to material, design, process and other reasons, which will cause the power transmission of the control system. Serious consequences of signal control interruption. Due to unreliable design, wrong material selection, improper selection of molding process, poor quality of heat treatment, mold, assembly, welding and other factors, improper assembly and other factors will cause poor fixation. 3. Poor insulation : the function of the insulator is to keep the contacts in the correct position and to insulate the contacts and the contacts, and between the contacts and the shell. Therefore, the insulating parts must have excellent electrical properties, mechanical properties and process forming properties. Especially with the widespread use of high-density and miniaturized terminals, the effective wall thickness of the insulator becomes thinner and thinner. This puts forward more stringent requirements on insulating materials, injection mold accuracy and molding process. Due to the existence of metal excess on the surface or inside of the insulator, surface dust, flux and other pollution and moisture, organic material precipitates and harmful gas adsorption film merge with the surface water film to form an ionic conductive channel, moisture absorption, mold growth, and aging of the insulating material. Will cause short-circuit, leakage, breakdown, low insulation resistance and other poor insulation. 15. Describe the testing procedures for accessing electrical terminals and using test probes correctly. A probe should never be wedged or pushed into a connector. Doing so will spread the contacts and ruin the connector. Instead very gently touch the metal portion of the connector with the lead. The red lead is normally used for checking connections and the black lead is touched to a metal part of the vehicle chassis or ground. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

For example we switch the meter to the volt scale in checking a light-socket for current flow. We touch the black lead to a body ground and the red lead to the metal contact to be checked. When the circuit is turned on the volt meter should register, indicating current flow. 16. Describe and explain the electrical measuring and testing procedures, listed in the table below. Electrical resistance checks Resistance can be calculated by measuring the current and voltage using Ohm’s Law. As a result, a circuit’s resistance value can be determined if the current and voltage measured values are known. Analog multimeters and digital multimeters employ the measurement principle of Ohm’s Law to measure resistance. Resistance measurement with an analog tester When measuring resistance with an analog multimeter, switch off power to the circuit under measurement. Plug the red test lead into the positive input terminal with the “+” mark and the black test lead into the COM input terminal. Switch the instrument to Ω mode and set the range button as appropriate based on the circuit’s anticipated resistance. Short the black and red test pins and set the needle to 0 Ω using the 0 Ω adjustment knob. Then place the red and black test pins in contact with both ends of the circuit under measurement and read the value indicated by the meter. Keep in mind that applying a voltage to the test leads while the instrument is set to resistance mode could damage the tester. Additionally, if you are unable to perform 0 Ω correction, the analog multimeter’s battery may be low. If you encounter this issue, check the battery's voltage.Always conduct zero adjustment when measuring resistance. (Mechanical and electrical zero adjustment) Situations where voltage is being applied is hazardous, therefore separation is critical. Open and short circuit tests Open Circuit and Short Circuit Test on Transformer The open circuit and short circuit test are performed for determining the parameter of the transformer like their efficiency, voltage regulation, circuit constant etc. These tests are performed without the actual loading and because of this reason the very less power is required for the test. The open circuit and the short circuit test gives a very accurate result as compared to the full load test. Voltage drop test A voltage drop test is the only effective way to find excessive resistance in high amperage circuits. It's a quick and easy test that doesn't require any disassembly and will quickly show you whether or not you've got a good connection or a bad one. To do a voltage drop test, you create a load in the circuit that's being tested. Then you use a digital volt meter (DVM) to measure /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

the voltage drop across the live connection while it is under the load. Voltage always follows the path of least resistance, so if the circuit or connection being tested has too much resistance some of the voltage will flow through the DVM and create a voltage reading. VOLTAGE DROP TESTING CAN ALSO BE USED TO DETECT CURRENTS IN CIRCUITS When current flows through a circuit, it creates heat. And heat increases resistance. A voltage drop test can be used to detect current flowing in a circuit by measuring voltage drop across the fuse that protects that circuit. This is a handy method for finding key-off current loads that may be draining the battery. With the key off, connect the two voltmeter leads to the opposite sides of each fuse in the fuse box or power center. If no current is flowing through a circuit, the voltage drop reading should be zero. If you get a reading (say a few tenths of a volt or more), it indicates current is still flowing in the circuit. This may be a normal load to maintain the memory in a module, or it may indicate the module is not going into "sleep mode" or a low power standby mode after the ignition has been turned off. Current flow tests Current is the measure of the rate of electron “flow” in a circuit. It is measured in the unit of the Ampere, simply called “Amp,” (A). The most common way to measure current in a circuit is to break the circuit open and insert an “ammeter” in series (in-line) with the circuit so that all electrons flowing through the circuit also have to go through the meter. Because measuring current in this manner requires the meter be made part of the circuit, it is a more difficult type of measurement to make than either voltage or resistance. Some digital meters, have a separate jack to insert the red test lead plug when measuring current. Other meters, like most inexpensive analog meters, use the same jacks for measuring voltage, resistance, and current. Consult your owner’s manual on the particular model of meter you own for details on measuring current. When an ammeter is placed in series with a circuit, it ideally drops no voltage as current goes through it. In other words, it acts very much like a piece of wire, with very little resistance from one test probe to the other. Consequently, an ammeter will act as a short circuit if placed in parallel (across the terminals of) a substantial source of voltage. If this is done, a surge in current will result, potentially damaging the meter: 17. Describe and explain the visual testing procedures, listed in the table below. Component moisture ingress Finding the water in your car isn't hard – It usually collects in the lowest spot, the foot wells! But diagnosing where it came from is notoriously hard. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

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We all know that water obeys the laws of gravity, so will always pool in the lowest area – but it can run along wires, travel up cardboard and fabric surfaces, and generally do its best to disguise where it came from in the first place! The first clue to help find the leak is WHEN it happens? Is it after a rain storm or car wash? Only when the car's parked on a slope? Was it just after using the heat or defroster for the first time in a long time? Or maybe the AC? Identifying when can potentially narrow down where and why. If it leaks even when it hasn't rained or the car hasn't been washed, then it's coming from somewhere within the car itself. If it only happens when the car is parked on a slope, it's probably a failed weatherstripping seal or blocked sunroof drain. Connector damage Visual inspection method when a part of the automobile electrical system breaks down, there will be abnormal phenomena such as smoke, spark, abnormal noise, scorching, high temperature, etc. Through the hearing, touching, smelling and seeing of the human body's sense organs, the vehicle wiring harness and electrical appliances are visually inspected to determine the fault location, thus greatly improving the maintenance speed. For example, when the car line breaks down, there are often abnormal phenomena such as smoke, sparks, abnormal noise, scorching, high temperature, etc. Through visual inspection, the location and nature of the fault can be quickly determined. 18. Describe and explain the repair procedures for electrical circuits, for the following: Wire soldering procedures Begin by removing the insulation from the ends of both wires you are soldering together. If the wire is stranded, twist the strands together with your fingers. Make sure your soldering iron is fully heated and touch the tip to the end of one of the wires. Hold it on the wire for 3-4 seconds. Keep the iron in place and touch the solder to the wire until it’s fully coated. Repeat this process on the other wire. Hold the two tinned wires on top of each other and touch the soldering iron to both wires. This process should melt the solder and coat both wires evenly. Remove the soldering iron and wait a few seconds to let the soldered connection cool and harden. Use heat shrink to cover the connection. Terminal crimping procedures Choose the Wire: The type of wire you need will depend on the application. Hence, understanding the equipment’s requirement can help you to find the right type. First, look at the wire size; this is generally given as AWG (American Wire Gauge). An example of this would be 16 AWG. If you do not have access to this information, there is another way to determine the wire size. Strip a small length of the wire insulation. Count the individual wire strands, and measure the diameter of one strand. You can then /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

multiply the number of strands by the diameter of one strand. Select the Crimp Terminal: There are a variety of crimp terminals to choose from. The quality of the crimp joint will depend a great deal on the terminal chosen. The following points need to be considered when choosing a terminal.  Plating – Terminals with plating ensure that there will be low contact resistance, and protection against corrosion.  Pre-insulation – These terminals consist of a metal sleeve, which is used to grip the wire.  Turned Pin – These are constructed from rod materials, and are almost round in shape. They support the creation of connectors. Decide on the Crimping Tool: Crimping tools come in a variety of designs. However, it is important that you select the tool that the crimp terminal is designed to be crimped with. Consult the crimp terminal manufacturers website for tooling information. If that is not an option, be sure to get a tool that will accept the crimp terminal and has a ratchet design. This will ensure that the crimp has been formed correctly. Make the Crimp: The crimping process consists of a few additional steps.  Determine the length of the wire, and strip the end. The stripping length should be such that when you insert the wire into the crimp, there should be at least 1 or 2 mm protruding from it. Cut the insulation off the end, and expose the wire strands.  Insert the wire into the crimp. Ensure that all the strands have been inserted into the crimp.  Place the crimp and wire into the crimping tool, and ensure that it is perfectly seated inside. Cycle the tool until it releases.  Remove the crimp, and inspect the wire. Ensure that it is in the correct position, and that the insulation is secure. Give the crimp and wire a tug to check that they are secured. When Using Heatshrink: Fit the sleeve over the crimp and wire. Ensure that the sleeve is at the right position, and is not covering the crimp’s terminal end. Use a hot air gun to shrink the tubing. Points of Warning  Never choose a solid wire. Only choose wires with individual strands.  Avoid any crimping tool that does not have a ratchet feature.  It would be a good idea to perform test crimps on other wires before performing the crimping process. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

Replacing male and female terminals in a connector housing To remove the male and female terminals look for the catch that holds them. Raise the catch and remove the terminal pin lightly at one time. Refit the new connectors in the reverse order. Connector removal and replacement procedures STEP 1 Pull the connection you want to disconnect up and away from the other wires around it. If you need to, use a pair of small scissors to cut the small plastic wire ties that may be holding the wires coming from the connection to the other bundles. You don't need much room but you will want to be able to get both your hands on the connection easily. STEP 2 Look closely at the connection. There will be a "female" end and a "male end". The male end inserts into the female end. Once you have identified which is the female end, look for a tab on the top or sides of the connection. If one is present, hold the female end in one hand and push down or in on the locking tab to release it. If there is no tab, hold the female end firmly in one hand. STEP 3 Pull the male end from the female receiver. Make sure you are grabbing the male end by the plastic of the connector and not the wires. Refit all the new connector in the same reverse order. Basic electrical components removal and replacement procedures Ensure that the voltage and frequency of your power source match the voltage and frequency inscribed on the equipment’s electrical rating label. Never push objects of any kind through openings in the equipment. Dangerous voltages might be present. Conductive foreign objects could produce a short circuit that could cause fire, electric shock, or damage to your equipment. 19. Describe the post-repair procedures listed in the table below. Circuit/System Description Confirming the electrical system is operating to manufacturers specifications. Use the multimeter to check the voltage, amps, current and continuity by connecting the positive and negative probes in the terminals of the circuit to find reading according to manufacturers specification. Confirming that no other problems are present as a result of the repair. Do a visual inspection for all the wires in the circuit. Check all the switches loads and wires. Check for the voltage, current, amps and continuity using a multimeter. /var/filecabinet/temp/converter_assets/d7/21/d721da7830e2b746b2c79372a0e47fd6b55edda4.docx

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AURETR112 Student Assessment - Theory

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