Electronical Technology GR 12 PAT 2022 (Power Systems) Eng

Downloaded from hlayiso.com ELECTRICAL TECHNOLOGY (POWER SYSTEMS) GUIDELINES FOR PRACTICAL ASSESSMENT TASKS (PAT) GRADE 12 2022 These PAT guidelines consist of 40 pages. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 2 DBE/PAT 2022 NSC TABLE OF CONTENTS PAGE 1. INTRODUCTION/BACKGROUND 3 2. TEACHER GUIDELINES 4 2.1 How to administer PAT 4 2.2 How to mark/assess PAT 4 2.3 PAT Programme of Assessment (PoA) 5 2.4 Moderation of PATs 6 2.5 Consequences of absence/non-submission of tasks 6 2.6 Simulations 7 2.7 Projects 7 2.8 Working Mark Sheet 8 3. LEARNER GUIDELINES 9 3.1 PAT 2022 Cover Page 9 3.2 Instructions to Learners 10 3.3 Declaration of Authenticity 10 4. SIMULATIONS 11 4.1 Simulation 1: RLC series circuit 11 4.2 Simulation 2: Three-phase transformer 15 4.3 Simulation 3: Automatic STAR-DELTA starter with overload 19 4.4 Simulation 4: Forward reverse motor starter with overload using PLC 23 5. SECTION B: DESIGN AND MAKE 29 5.1 Design and make: Part 1 30 5.2 Assessment of the design and make phase: Part 1 33 5.3 Design and make: Part 2 35 5.4 Assessment of design and make phase: Part 2 36 6. PROJECTS 37 6.1 Practical project 6.1: Plug tester 37 6.2 Practical project 6.2: Inverter 100 W 12 VDC to 230 VAC by IC 4047 IRF 540 38 6.3 Practical project 6.3: Automatic LED emergency light 39 7. CONCLUSION 40 Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 3 DBE/PAT 2022 NSC 1. INTRODUCTION The 18 Curriculum and Assessment Policy Statements subjects which contain a practical component all include a practical assessment task (PAT). These subjects are:  AGRICULTURE: Agricultural Management Practices, Agricultural Technology  ARTS: Dance Studies, Design, Dramatic Arts, Music, Visual Arts  SCIENCES: Computer Applications Technology, Information Technology, Technical Sciences; Technical Mathematics  SERVICES: Consumer Studies, Hospitality Studies, Tourism  TECHNOLOGY: Civil Technology, Electrical Technology, Mechanical Technology and Engineering Graphics and Design A practical assessment task (PAT) mark is a compulsory component of the final promotion mark for all candidates offering subjects that have a practical component and counts 25% (100 marks) of the end-of-the-year examination mark. The PAT is implemented across the first three terms of the school year. This is broken down into different phases or a series of smaller activities that make up the PAT. The PAT allows for learners to be assessed on a regular basis during the school year and it also allows for the assessment of skills that cannot be assessed in a written format, e.g. test or examination. It is therefore important that schools ensure that all learners complete the practical assessment tasks within the stipulated period to ensure that learners are resulted at the end of the school year. The planning and execution of the PAT differs from subject to subject. Practical assessment tasks are designed to develop and demonstrate a learner's ability to integrate a variety of skills in order to solve a problem. The PAT also makes use of a technological process to inform the learner what steps needs to be followed to derive a solution for the problem. The PAT consists of four simulations and a practical project. The teacher may choose any ONE of the practical projects and any TWO simulations available for POWER SYSTEMS. The teacher must apply assessment on an ongoing basis at the same time that the learner is developing the required skills. TWO simulations should be completed by the learners, in addition to the manufacturing of a practical project. The PAT incorporates all the skills the learner has developed throughout the year. The PAT ensures that all the different skills will be acquired by learners on completion of practical work, as well as the correct use of tools and instruments. Requirements for presentation A learner must present the following:  PAT file with all the evidence of simulations, design and prototyping. A copy of the PAT 2022 cover page. The relevant simulations and assessment sheets should be copied and handed to each learner to include in the file.  Practical project with: o Enclosure:  The file must include a design.  The enclosure and the design must match.  No cardboard boxes are allowed.  Plastic, wooden and metal enclosures are acceptable.  Enclosures that are manufactured and/or assembled by the learners are preferred.  The enclosure should be accessible for scrutiny inside.  Lids that are secured are preferred. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 4 DBE/PAT 2022 NSC o Circuit board:  The file should include the PCB design.  The PCB must be mounted inside the enclosure in such a manner that it can be removed for scrutiny. Alternatively, inspection can be made from the bottom in cases where translucent (see-through) enclosures are used.  Switches, potentiometers, connectors and other items must be mounted.  Wiring must be neat and bound/wrapped.  Wiring must be long enough to allow for the PCB to be removed and inspected with ease. o Logo and name:  The file should contain the logo and name design and specification plate.  Logo, specification plate and name must be prominent on the enclosure.  The logo/specification plate must be affixed in a permanent manner – painted, glued or stuck on with vinyl The PAT will have a financial impact on the school's budget and school management teams are required to make provision to accommodate this particular expense. PAT components and other items must be acquired timeously, for use by the learners, before the end of the first term at the start of the academic year. It is the responsibility of the HOD to ensure that the teacher is progressing with the PAT from the start of the school year. Provincial departments are responsible for setting up moderation timetables and consequently PATs should be completed in time for moderation. 2. TEACHER GUIDELINES 2.1 How to administer PATs Teachers must ensure that learners complete the simulations required for each term. The project should be started in January in order to ensure its completion by August. In instances where formal assessments take place, the teacher has to assume responsibility therefore. The PAT should be completed during the FIRST THREE TERMS and must be ready at the start of PAT moderation. Teachers must make copies of the relevant simulations and hand them to learners at the beginning of each term. The PAT must not be allowed to leave the workshop and must be kept in a safe place at all times when learners are not working on them. The weightings of the PAT must be adhered to and teachers are not allowed to change weightings for the different sections. 2.2 How to mark/assess the PATs The PAT for Grade 12 will be set and assessed internally, but moderated externally. All formal assessment will be done by the teacher. The teacher is required to produce a working model and model answer file that sets the baseline for assessment at a Highly Competent Level for every project choice exercised by the learners. This file must include all the simulations with answers the teacher has done him/herself. The teacher will use the model answers and project to assess the simulations and projects of the learners. Once a facet sheet has been completed by the teacher, assessment will be deemed to be complete. No re-assessment will be done once the facet sheets have been completed and captured by the teacher. Learners must ensure that the work is done to the required standard before the teacher finally assesses the PAT during each stage of completion. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 5 DBE/PAT 2022 NSC 2.3 PAT Programme of Assessment (PAT PoA) The programme of assessment (PoA) for the PAT is as follows: TIME FRAME ACTIVITY RESPONSIBILITY Preparation for Teacher – Builds the models and works out the model answers for PAT 2022 the simulations for 2022. Identifies shortages in tools, equipment and consumable items for simulations that must be procured in 2022. SMT – Receives procurement requests from teachers and processes payments for the acquisition of required items January–March Simulation 1 Teacher – Copies and hands out simulations 2022 Learners – Complete simulations Teacher – Assesses simulations HOD – Checks if tasks have been completed and marked by the teacher before the holiday January 2022 PAT project – Teacher – Obtains quotations for PAT projects procurement Principal – Approves PAT procurement for PAT projects Teacher – Ensures that PAT projects are ordered and delivered HOD – Checks in on teacher to see if the process is adhered to February 2022 PAT project – Teacher – Ensures that there is secure storage for PAT projects learners Teacher – Hands out and takes in PAT projects commence with Teacher – Includes practical sessions for learners to complete the project PAT project every week Learners – Commence with completion of the PAT project HOD – Checks in on teacher to ensure that practical workshop sessions take place on a weekly basis April–June Simulation 2 Teacher – Copies and hands out simulations 2022 Learners – Complete simulations Teacher – Assesses simulations HOD – Checks if tasks have been completed and marked by the teacher before the holiday April–June Moderation of District subject facilitator/subject specialist will visit the school and 2022 Simulation 1 moderate simulation 1 10% of learners' work is moderated April–June PAT project – Teacher – Ensures that there is secure storage for PAT projects 2022 learners Teacher – Hands out and takes in PAT projects continue with Teacher – Includes practical sessions for learners to complete the project PAT project every week Learners – Continue with completion of the PAT project HOD – Checks in on teacher to ensure that practical workshop sessions take place on a weekly basis July holidays PAT Learners that are behind on the PAT are required to complete the 2022 intervention project during this holiday. July–August Moderation of District subject facilitator/subject specialist will visit the school and 2022 Simulation 2 moderate simulation 2 – different learners from the previous term 10% of learners' work is moderated July–August PAT project – Teacher – Ensures that there is secure storage for PAT projects 2022 completion Teacher – Hands out and takes in PAT projects Teacher – Completes the PAT project with learners and compiles the PAT file Learners – Complete the PAT project and file HOD – Checks to see that 100% of the PAT files and projects are completed and assessed September– PAT PAT projects are moderated by subject facilitators/subject October 2022 moderation specialists from the province and learners are available to demonstrate skills 10% of learners are moderated randomly Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 6 DBE/PAT 2022 NSC 2.4 Moderation of PATs Provincial moderation of each term's simulations will start as early as the following term. Simulation 1 should be moderated as soon as the second term starts. Similarly, Simulation 2 will be moderated in July. The project will, however, only be moderated on completion. During moderation of the PAT the learner's file and project must be presented to the moderator. The moderation process is as follows:  During moderation, learners are randomly selected to demonstrate the different simulations. Both simulations will be moderated.  The teacher is required to build a model of each project chosen for the school.  This model must be on display during moderation.  The teacher's model forms the standard of the moderation at Level 4 (Highly Competent).  Level 5 assessments must exceed the model of the teacher in skill and finishing.  Learners who are moderated will have access to their files during moderation and may refer to the simulations they completed earlier in the year.  Learners may NOT ask assistance from other learners during moderation.  All projects and files must be on display for the moderator.  If a learner is unable to repeat the simulation or cannot produce a working circuit during moderation, marks will be deducted and circuits assessed as not being operational.  The moderator will randomly select no fewer than two projects (not simulations) and the learners involved will have to explain how the project was manufactured.  Where required, the moderator should be able to call on the learner to explain the function and principles of operation, and request the learner to exhibit the skills acquired through the simulations for moderation purposes.  On completion the moderator will, if needed, adjust the marks of the group upwards or downwards, depending on the outcome of moderation.  Normal examination protocols for appeals will be adhered to, if a dispute arises from adjustments made. 2.5 Absence/Non-submission of Tasks The absence of a PAT mark in Electrical Technology without a valid reason: The learner will be given three weeks before the commencement of the final end-of-year examination to submit outstanding task. Should the learner fail to fulfil the outstanding PAT requirement, such a learner will be awarded a zero (0) for that PAT component. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 7 DBE/PAT 2022 NSC 2.6 Simulations Simulations are circuits, experiments and tests/tasks which the learner will have to build, test and measure and practically do as part of the development of practical skills. These skills have to be illustrated to the external moderator that visits the school at intervals during the school year. Teachers who use simulation programs on a computer may use them for the learners to practice on. However, it is required that the circuit be built using real components and that measurements be made with actual instruments for the purposes of assessment and moderation. The correct procedure for completing simulations is outlined below for teachers and school management teams who are responsible for the implementation of the PAT in Electrical Technology. STEP 1: The teacher will choose simulations from the provided examples. STEP 2: Compile a list of the components needed for every simulation. Add extra components as these items are very small and you will need extras, as these items are lost/damaged very easily when learners work with them. STEP 3: Contact three different electronics component suppliers for comparative quotations. STEP 4: Submit the quotations to the SMT for approval and procurement of the items. STEP 5: Place the components in storage. Collate items for each simulation, thus making it easier to distribute and use during practical sessions. Ensure that different values of components do not mix, as this would lead to components being used incorrectly and this could damage the component and in extreme cases, the equipment used. STEP 6: Copy the relevant simulations and hand them out to learners at the start of the term. Teachers are allowed to adjust circuits and component values to suit their environment/ resource availability. Teachers are required to develop a set of model answers in the teacher's file. Moderators will use the teacher's model answers and artefacts when moderating. 2.7 Projects The projects are construction projects teachers can choose for their learners. These projects are based on proven circuits provided from schools and subject advisors. The projects are based on working prototypes and require careful construction in order for them to operate correctly. Projects vary in cost and teachers must ensure that the projects chosen fall within the scope of the school's budget. Once the teacher has decided on a circuit, he/she must construct the prototype. Thereafter, copies of the provided circuit can be made and distributed to learners. They MUST redraw these circuits in their portfolios correctly. The description of the operation of the circuits is NOT complete. Learners are required to interrogate the function of the components in the provided circuit. They should elaborate on the purpose of components in the circuit. It is recommended that learners investigate similar circuits available on the internet and in the school library or workshop reference books. Copyright reserved Please turn over

Electrical Technology: Power Systems Downloaded from hlayiso.com 8 DBE/PAT 2022 NSC 2.8 Working mark sheet (A working Excel file is provided with this PAT) Moderated Mark PAT mark sheet Term 1 Term 2 Project Mark out of 100 Simulation 1 Simulation 2 Design Design Total = Term 1 + and and Make Term 2 + Project 50 50 Make Part 2 250 Part 1 30 No. Name of Learner 120 Total Average Teacher Name: Principal Name: Moderator Name: Signature: Signature: Signature: Date: Date:_______________________ Date:__________________ Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 9 DBE/PAT 2022 NSC 3. LEARNER GUIDELINES PAT 2022 cover page (Place this page at the front of the PAT.) Department of Basic Education Grade 12 CAPS for Technical High Schools Practical Assessment Task – Electrical Technology Time allowed: Terms 1–3 (2022) Learner Name: Class: School: Specialisation: POWER SYSTEMS Complete TWO simulations. Project (Write the name of the project): _____________________________ Evidence of moderation: NOTE: When the learner evidence (LE) selected has been moderated at school level, the table will contain evidence of moderation. Provincial moderators will sign the provincial moderation and only sign if re-moderation is needed. Moderation Signature Date Signature Date School-based District moderation Provincial moderation Re-moderation Mark allocation Moderated PAT Component Maximum Mark Learner Mark Mark Simulation 1 50 Simulation 2 50 Design and Make Project – Circuit 120 Design and Make Project – Enclosure 30 Total 250 Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 10 DBE/PAT 2022 NSC 3.1 Instructions to learner  The practical assessment task counts 25% of your final promotion mark.  All work produced by you must be your own effort. Group work is NOT allowed.  The practical assessment task must be completed over three terms.  The PAT file must contain TWO simulations and a practical project.  Calculations should be clear and include units. Calculations should be rounded off to TWO decimals. SI units should be used.  Circuit diagrams can be hand-drawn or drawn on CAD. NO photocopies or scanned files are allowed.  Photos are allowed and may be in colour or greyscale. Scanned photos and photocopies are allowed.  Learners with identical photos will be penalised and receive zero for that section.  This document must be placed inside your PAT file together with the other evidence. 3.2 Declaration of Authenticity (COMPULSORY) Declaration: I (Name) herewith declare that the work represented in this File/evidence is entirely my own effort. I understand that if proven otherwise, my final results may be withheld. Signature of learner Date Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 11 DBE/PAT 2021 NSC 4. SIMULATIONS 4.1 Simulation 1: RLC series circuit Name of learner: Mark Class: Date Completed: _______ 50 Date Assessed: Assessor Signature: ______________ Date Moderated: Moderator Signature: ______________ 4.1.1 Purpose:  To understand the operation of a resistor, inductor and capacitor in a series circuit with an AC supply.  To understand resonant frequency.  To compare the measured and the calculated values. 4.1.2 Procedure: Build the series RLC circuit in FIGURE 4.1.4 on the breadboard using the components provided. Connect the circuit to a function generator. Set the output signal voltage of the function generator to 5 V with a frequency of 50 kHz. Take the measurements as asked in TABLE 4.1.5 with the frequency adjusted to 50 Hz, 159 Hz and 500 Hz and then answer the questions that follow. 4.1.3 Required resources: COMPONENTS TOOLS AND EQUIPMENT R1 = 100 Ω resistor Multimeter L1 = 10 µH inductor Function generator C1 = 100 µF capacitor Leads Breadboard Side cutters Pair of pliers Oscilloscope Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 12 DBE/PAT 2021 NSC 4.1.4 Circuit Diagram: L1 R1 C1 VR VL VC It 5V 50-500Hz Vt FIGURE 4.1.4: RLC CIRCUIT DIAGRAM 4.1.5 Complete TABLE 4.1.5 by entering measured values of VR, VL, VC, VT and IT. NOTE: Alternatively measure with the oscilloscope and convert to Vrms values. METERS MEASUREMENTS MEASUREMENTS MEASUREMENTS CONNECTED AT 50 Hz AT 159 Hz AT 500 Hz ACROSS VR VL VC VT IT TABLE 4.1.5 (13) 4.1.6 Study the measurements in TABLE 4.1.5 above and answer the following: (a) Compare the values of VL and VC at 50 Hz. (2) (b) Calculate the values of XL and XC at 50 Hz with: (4) XL = XC = Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 13 DBE/PAT 2021 NSC (c) Compare the values of VL and VC at 500 Hz. (2) (d) Calculate the values of XL and XC at 500 Hz. (4) XL = XC = (e) Compare the values of VL and VC at 159 Hz. (2) (f) Calculate the values of XL and XC at 159 Hz. (4) XL = XC = (g) Calculate the resonant frequency. (3) 4.1.7 Write a conclusion about the measurements in 4.1.5 and calculations in 4.1.6 when the circuit is at resonance. (4) RUBRIC FOR SIMULATION 1 LEVEL DESCRIPTOR MARKS OBTAINED 0 1 2 4 The learner was The learner was The learner was able to The learner built the not able to build able to partially correctly build the circuit circuit correctly without the circuit on his build the circuit on with the assistance of the assistance of the own. his own. the teacher. teacher. The learner was The learner was The learner connected The learner connected not able to able to partially the measuring the measuring connect the connect the instruments correctly instruments correctly measuring measuring and measured the and measured the instruments. instruments to the voltages and currents voltages and currents circuit. with the assistance of on his own. the teacher. (12) Total: [50] Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 14 DBE/PAT 2021 NSC 4.2 Simulation 2: Three-phase transformer Name of learner: Mark Class: Date Completed: 50 Date Assessed: Assessor Signature: Date Moderated: Moderator Signature: 4.2.1 Purpose:  To connect three identical single-phase step-down transformers in star-delta to a three-phase supply.  To connect the secondary to a load that consists of three identical incandescent lamps that are connected in delta.  To measure the primary and secondary line and phase voltages and currents. 4.2.2 Required resources: TOOLS/INSTRUMENTS/DEVICE CONSUMABLES Three identical step-down single-phase Connecting wires transformers Three identical incandescent lamps Three-phase supply Clamp meter and multimeter Wire stripper Long-nose pliers Screw driver Side cutters Isolation tester (Megger) 4.2.3 Procedure: Connect the primary windings of each transformer to the supply and the secondary to the load (lamp). Complete TABLE 4.2.3 by measuring the primary and secondary voltages of each single-phase transformer before connecting them in star-delta configuration. NOTE: Use single phase to connect (live and neutral). Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 15 DBE/PAT 2021 NSC Primary Secondary Transformer A V winding winding V Primary Secondary Transformer B V winding winding V Primary Secondary Transformer C V winding winding V FIGURE 4.2.3: THREE SINGLE-PHASE TRANSFORMERS TRANSFORMER PRIMARY SECONDARY VOLTAGE VOLTAGE A VPrim(A) = VSEC(A) = B VPrim(B) = VSEC(B) = C VPrim(C) = VSEC(C) = TABLE 4.2.3 (6) 4.2.4 Calculate the transformer ratio of each single-phase transformer using the voltage values from TABLE 4.2.3. It only has to be done once. The transformers are identical. TRANSFORMER A TRANSFORMER B TRANSFORMER C TR = TR = TR = (3 x 3) (9) 4.2.5 Explain whether these transformers are fit to be used as a star-delta connected three-phase unit. NOTE: Your answer must be informed by transformer ratio calculations. (2) Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 16 DBE/PAT 2021 NSC 4.2.6 Draw the circuit diagram in which these transformers are connected in a star-delta configuration using colour coding and correct labelling. Show the connection of the load. STAR-DELTA CONFIGURATION TRANSFORMER NOTE: 3 marks for primary connection (3 x line and 1 neutral) 3 marks for secondary connection (3 x line) 3 marks for load connection (3 x line) (Any 9 marks) (9) 4.2.7 Connect THREE identical single-phase step-down transformers in star-delta to a three-phase supply. Connect the primary (star) to the three-phase supply and the secondary (delta) to a load that consists of three identical incandescent lamps. The lamps must be connected in delta too. NOTE: The secondary voltage of the transformer is not critical. The only requirement is that the secondary voltage and the voltage of the lamps must be compatible. It is the duty of the teacher to verify that the learners connect the transformers correctly, before connecting the mains supply. If you are not entirely sure of your connections do NOT switch on. Test for short circuits. Mains supply can be lethal. Be extremely careful. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 17 DBE/PAT 2021 NSC 4.2.8 Measure the primary and secondary line and phase voltages and currents. Record the readings in the table below. Primary side Readings on line voltages, phase voltages and line currents VL1 & VL2 = VL1 & N = IL1 = VL1 & VL3 = VL2 & N = IL2 = VL2 & VL3 = VL3 & N = IL3 = Secondary side Readings on line voltages, phase voltages and line currents VL1 & VL2 = IPH1 = IL1 = VL1 & VL3 = IPH2 = IL2 = VL2 & VL3 = IPH3 = IL3 = (18) 4.2.9 Calculate the primary apparent power. (3) 4.2.10 CONCLUSION: Your conclusion must be based on the table above and other observations. (3) [50] Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 18 DBE/PAT 2022 NSC 4.3 Simulation 3: Automatic STAR-DELTA starter with overload Name of learner: Mark Class: Date Completed: 50 Date Assessed: Assessor Signature: Date Moderated: Moderator Signature: 4.3.1 Purpose:  To investigate the effect of a star-delta motor with reference to current and voltage at start-up. 4.3.2 Required Resources TOOLS/INSTRUMENTS MATERIAL 2 x three-phase contactors with auxiliary Multimeter or continuity tester contacts (for forward and reverse connection) Multimeter or voltmeter 1 x three-phase main contactor Clamp-on ammeter 1 x three-phase overload relay 1 x stop button 1 x start button 1 x three-phase induction motor Tools Correct wire size or plug-in leads Wire-stripper Long-nose pliers Screwdriver Side cutters Build the control and the power circuit on the panels and let the teacher check the circuits before switching on. After the start button is pressed and released, the motor will run in star. When the motor has reached near or rated speed, it switches into delta or after a pre-set time, the motor will switch into delta. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 19 DBE/PAT 2022 NSC FIGURE 4.3.2(a): AUTOMATIC STAR-DELTA CONTROL CIRCUIT Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 20 DBE/PAT 2022 NSC L1 L2 L3 1 3 5 1 MC1 2 2 4 6 1 3 5 OL 2 4 6 U1 V1 W1 Motor Terminal box 2 4 6 MC2 2 4 6 MC3 W2 U2 V2 Y Δ 1 3 5 1 3 5 FIGURE 4.3.2(b): AUTOMATIC STAR-DELTA POWER CIRCUIT 4.3.3 Procedure: Consider all safety aspects before and during the wiring process and be cautious until the motor is operating. (a) Wire and test the control circuit before connecting it to the power circuit. Ask your teacher to check the control circuit before switching on the supply. (b) Wire the power circuit and connect it to the control circuit. Ask your teacher to check the power circuit before switching on the supply. (c) Start the motor and observe. (d) Use a voltmeter to measure the required voltages in TABLE 4.3.4(a). (e) Use an ammeter to measure the required currents in TABLE 4.3.4(b). (f) The teacher will insert faults on the control circuit and the learner must identify and correct them. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 21 DBE/PAT 2022 NSC 4.3.4 Activity 3: (a) Complete the table below by measuring the phase voltages of the motor when it is running in star and after it switches to delta. (Use a voltmeter and set it to the highest scale.) PHASE VOLTAGES STAR DELTA Phase 1 Phase 2 Phase 3 TABLE 4.3.4(a) (6) (b) Complete the table below by measuring the currents drawn from the supply when the motor is running in star and after it switches to delta. (Use a clamp-on meter.) LINE CURRENTS STAR DELTA Line 1 Line 2 Line 3 TABLE 4.3.4(b) (6) (c) Study the measurements in TABLE 4.3.4(a) and compare the voltages in star to the voltages in delta. (2) (d) Study the measurements in TABLE 4.3.4(b) and compare the currents in star to the currents in delta. (2) (e) Write a conclusion based on the measurements in TABLES 4.3.4(a) and (b). (4) [20] Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 22 DBE/PAT 2022 NSC FACET: SIMULATION 3: THE STAR-DELTA STARTER FACETS FACET 1 FACET 2 FACET 3 MAXIMUM LEARNER'S POSSIBLE MARKS MARK Preparation of the Testing the functionality Correctly identifying and Correctly identifying and 3 marks max. simulation of all devices to be used collecting all contactors collecting all tools and (stop/start buttons, and components (1) measuring instruments contactors, etc.) (1) (1) Wiring of control Correct procedure when Wiring the control circuit: Correct colour coding 5 marks max. circuit wiring the circuit (1) Without assistance (3) used for wiring the Being assisted once (2) control circuit (1) Being assisted more than once (1) Operation of the Power circuit works Power circuit works 5 marks max. control circuit partially (2) correctly (5) Use of measuring Correct use of continuity Correct use of ammeter Correct use of voltmeter 3 marks max instruments tester (1) (1) (1) Wiring of power Correct procedure when Wiring the power circuit: Correct colour coding 5 marks max. circuit wiring the circuit (1) Without assistance (3) used for wiring the Being assisted once (2) power circuit Being assisted more than (1) once (1) Operation of the Power circuit works Power circuit works 5 marks max. power circuit partially (2) correctly (5) Setting of fault and fault Fault successfully Fault successfully Safety precautions were 3 marks max finding identified (1) corrected (1) observed (1) Housekeeping Housekeeping was 1 mark max practised (1) Facet Total: (30) Activity: (20) Facet Marks: (30) TOTAL: [50] Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 23 DBE/PAT 2022 NSC 4.4. Simulation 4: Forward-reverse motor starter with overload using PLC Name of learner: Mark Class: Date Completed: 50 Date Assessed: Assessor Signature: Date Moderated: Moderator Signature: 4.4.1 Purpose:  To modernise an old relay panel forward-reverse motor starter and change it to a PLC system. Scenario: A company is under new management and decided to update their old relay systems to PLC systems. One system that needs updating is an electric motor that can turn in forward and reverse direction by pushing two different start buttons, one for forward and another for reverse. When the motor is turning in the forward direction, it must be stopped first before starting it in reverse. It must not be able to change direction without pressing the stop button. Overload protection is used to monitor the current to the motor. The overload relay must disconnect the current to the motor the moment it surpasses the rated current. Control circuit: FIGURE 4.4.1(a): RELAY LOGIC CONTROL CIRCUIT Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 24 DBE/PAT 2022 NSC L NO NC STOP START OL Input 1 Input 2 Input 3 Input 4 Input 5 Input 6 Input 7 Input 8 L N Supply PLC Unit Output Q1 Output Q2 Output Q3 Output Q4 Common for Outputs A1 A1 A2 MC1 A2 MC2 FWD REV The PLC wiring might differ when using different PLC units. FIGURE 4.4.1(b): PLC UNIT CONNECTED TO THE CONTROL CIRCUIT Inputs to the PLC X1/I01 = O/L X2/I02 = Stop button X3/I03 = Start button Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 25 DBE/PAT 2022 NSC L1 L2 L3 1 3 5 OL 2 4 6 1 3 5 MC1 1 3 5 MC2 1 2 2 4 6 FWD 2 4 6 REV U1 V1 W1 Motor Terminal box W2 U2 V2 FIGURE 4.4.1(c): FORWARD-REVERSE POWER CIRCUIT Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 26 DBE/PAT 2022 NSC 4.4.2 Resources Required TOOLS/INSTRUMENTS MATERIALS Multimeter/Clamp meter or continuity Connecting wires tester PLC unit Computer/Programmer 1 x three-phase induction motor Programming cable 1 x three-phase overload relay Wire-stripper 1 x stop button Long-nose pliers 1 x start button Screwdriver 2 x three-phase contactors Side cutters 4.4.3 Procedure  Convert the relay logic circuit in FIGURE 4.4.1(a) into a ladder logic program.  Program the ladder logic diagram through a computer.  Run the PLC program in the computer and simulate the operation.  Load the program from a computer to a PLC.  Ensure the PLC is in run mode.  Disconnect the programming cable.  Switch off the supply.  Connect the PLC to the control the circuit.  Only switch ON the supply after your teacher has checked the circuit and confirmed it as correct.  If the program and control circuit is working, switch OFF the power supply.  Wire the power circuit to the motor.  Ask your teacher to check the wiring of the power circuit before switching it ON.  The teacher will insert faults on the PLC and the learner must identify and correct them.  Ask your teacher to inspect the circuit and ensure that all faults are corrected. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 27 DBE/PAT 2022 NSC 4.4.4 (a) Take a snapshot (screenshot) of the programmed ladder logic diagram. Save, print and paste it in the blank space below. Ensure that your name and the circuit name appear in the title block of the circuit. (10) (b) Explain the purpose of interlocking in this motor starter. (2) [12] Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 28 DBE/PAT 2022 NSC FACET SHEET FOR SIMULATION 4: THREE-PHASE FORWARD-REVERSE MOTOR CONTROL STARTER WITH OVERLOAD USING PLC MAXIMUM LEARNER'S FACETS FACET 1 FACET 2 FACET 3 FACET 4 POSSIBLE MARK MARKS Preparation of the Testing the functionality of Correctly identifying and Correctly identifying and 3 marks simulation all devices to be used collecting all contactors collecting all tools and max. (stop/start buttons, and components (1) measuring instruments (1) contactors etc.) (1) PLC unit Develop the ladder logic Correctly connecting the Correctly loading the program Run the program to 10 marks diagram in the computer PLC unit to control the from the computer to the test the control max. correctly (1) circuit with: PLC unit: circuit: No assistance (5) Without assistance (2) Without assistance Assistance once (4) With assistance (1) (2) Assistance more than With assistance (1) once (2) Operation of the Control circuit worked Circuit worked correctly 5 marks control circuit partially (2) (5) max. Fault finding The faults were correctly The faults were corrected 3 marks identified (1) without assistance (2) max. The faults were corrected with assistance (1) Wiring of power Correct procedure in wiring Correct colour coding. Correctly connecting the power Testing continuity in 8 marks max. circuit the circuit (1) Main circuit. circuit with: the circuit (1) (L1 red, L2 yellow, L3 No assistance (5) blue) (1) Assistance once (4) Assistance more than once (2) Operation of the Power circuit worked Power circuit worked 5 marks power circuit partially (2) correctly (5) max. Safety Safety precautions were Safety precautions were 2 marks max. observed after being observed without being reminded (1) reminded (2) Housekeeping Housekeeping was Housekeeping was 2 marks max. practised after being practised without being reminded (1) reminded (2) ACTIVITY FOR SIMULATION 4: (12) FACET SHEET FOR SIMULATION 4: (38) TOTAL: [50] Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 29 DBE/PAT 2020 NSC 5. SECTION B – DESIGN AND MAKE Design and Make Project Time: January to August 2022 Learner Name: School: Class: Title/Type of Project: INSTRUCTIONS  This section is COMPULSORY for all learners.  The teacher will choose a circuit for the project.  Any project constructed must include at least (but is not limited to): o Seven components o A variety of components (both active and passive) o PCB making in some form o Soldering o An enclosure with a switch and protection  The checklist below must be used to ensure that all the required tasks for the PAT have been completed. PAT CHECKLIST The learner MUST complete this checklist for the teacher BEFORE marking of the section takes place! NO. DESCRIPTION TICK () NO YES Design and Make: Part 1 1. Circuit diagram drawn   2. Circuit description filled in   3. Component list completed   4. Tools list for circuitry populated   5. Measuring instrument list filled in   6. Evidence of prototyping printed and pasted into the file   7. Learner's own Vero board/PCB planning/design printed and included in file   Design and Make: Part 2 1. Enclosure design completed and included in the file   2. Unique name written down and on the enclosure   3. Logo designed and on the enclosure   Miscellaneous 1. Enclosure included in the project   2. Enclosure prepared and drilled according to the design   3. Enclosure finished off and completed with name and logo   4. PCB securely mounted in the enclosure using acceptable techniques   5. Circuit inside the enclosure accessible   6. Internal wiring neat and ready for inspection   7. File and project completed and ready for moderation at the workshop/room   Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 30 DBE/PAT 2020 NSC 5.1 Design and make: Part 1 5.1.1 Circuit diagram Draw a circuit diagram of your project and add it after this page. 5.1.2 Project: Description of operation Use the space below to provide an overview of how the project functions. Use your own words and do some research of your own. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 31 DBE/PAT 2020 NSC 5.1.3 Component list Draw up a list of components you will need from the circuit diagram. LABEL DESCRIPTION AND VALUE QUANTITY 5.1.4 Tools/Instrument list Draw up a list of tools you will need to complete the PAT circuitry. You may add to the list as you proceed through the PAT. DESCRIPTION PURPOSE/USE Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 32 DBE/PAT 2020 NSC 5.2 Assessment of the design and make phase: Part 1 NO. FACET DESCRIPTION Mark Achieved = 1 Not achieved =  Circuit Diagram 1. The circuit diagram was drawn using EGD equipment. 5 2. The circuit diagram was drawn using CAD/any electronic 1 design software. 3. The circuit diagram was drawn using correct symbols. 3 4. The circuit diagram has all labels – R1, C1, Tr1, etc. 3 5. The circuit diagram has all component values –100 Ω, 4 220 μF, etc. 6. The circuit diagram has a name/title. 2 7. The circuit diagram has a frame and title block. 2 (EGD approach). Circuit Diagram Subtotal: 20 Component List 8. Labels correlate with circuit diagram. 2 9. Description and values correlate with circuit diagram. 2 10. Quantities are correct. 1 Component List Subtotal: 5 Description of Operation 11. Basic function of the circuit is described correctly. 10 12. All subcircuits in the circuit diagram and component list are 5 included in the description. 13. Purposes of subcircuits in the circuit diagram are described 5 correctly. 14. Learner used own interpretation and did not copy from 4 another source verbatim. 15. Sources are acknowledged. 1 Description of Operation Subtotal: 25 Tools/Instrument List 16. The tools/instrument list has been completed. 4 17. The tools/instruments listed all have a purpose for being used. 1 Tools/Instrument List Subtotal: 5 Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 33 DBE/PAT 2020 NSC NO. FACET DESCRIPTION Mark Achieved = 1 Not achieved =  Circuit Board Manufacturing 18. Transfer of the PCB design onto the blank board is correct. 5 Not over exposed or under exposed. 19. Circuit board is etched neatly according to the PCB design. 10 20. The learner's name is etched onto the circuit design. 4 21. All burrs are removed. 2 22. Axial and radial components are placed neatly and flush with 5 the board. 23. Component orientation are aligned between similar 2 components (e.g. the gold band of all resistors are placed on the same side). 24. Soldered components – leads are cut off, flush and neat on 5 the solder side. 25. More than 60% of the solder joints are shiny (not dry joints). 5 26. Wire insulation is stripped to the correct length (no extra 3 copper showing). 27. Wiring is long enough to allow for dismantling and inspection. 2 28. Wiring is wrapped neatly. 2 29. A power switch is included and fitted to the enclosure. 2 30. Wiring entering/exiting the enclosure is provided with a 2 grommet/applicable fittings/sockets where applicable. 31. A fuse/Protection is included and fitted correctly where 2 applicable. 32. Batteries/Transformer is mounted using a battery housing/ 2 mounting bracket and battery clip (NO double-sided tape). 33. The project has a pilot light/LED installed in the enclosure 2 showing when the circuit is operational. LED is mounted with a grommet or applicable fitting. (Switch is on – must go out when fuse is blown.) 34. The project is fully operational and commissioned/installed in 10 the enclosure. Circuit Board Manufacturing Subtotal: 65 Circuit Diagram Subtotal: 20 Component List Subtotal: 5 Description of Operation Subtotal: 25 Tools/Instrument List Subtotal: 5 Circuit Board Manufacturing Subtotal: 65 TOTAL (PART 1 = 120 marks) NOTE: In projects where facets are not applicable, the projects should be marked and the totals adjusted accordingly. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 34 DBE/PAT 2020 NSC 5.3 Design and make: Part 2 5.3.1 Enclosure design  Design an enclosure for your project.  NO FREEHAND DRAWINGS.  Draw using EGD equipment OR use a CAD program.  Draw in first-angle orthographic projection.  Add your drawings after this page.  Use colour to enhance your drawing. 5.3.2 Manufacture the enclosure neatly according to your design. You may use pre-cut panels from metal, wood and or Perspex/plexiglass. You must however construct/assemble these parts. Injection moulded enclosures are also acceptable. It is important that your enclosure and the placement of the parts align with your design. 5.3.3 Choose a name for your device. Write down the name of the device below. 5.3.4 Design a unique logo for your device, as well as a specification plate and attach it after this page. [20] Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 35 DBE/PAT 2020 NSC 5.4 Assessment of the design-and-make-phase: Part 2 NO. FACET DESCRIPTION Mark Achieved = 1 Not achieved =  Enclosure Design 1. Enclosure design is included in first-angle orthographic projection. 2 2. Drawn design includes a title box and page border. 1 3. Isometric drawing included additionally. 2 4. Dimensions are included. 2 5. The name of the device is written in the PAT document. 1 6. The logo design and specification plate design is in the 2 PAT document. Enclosure Design Subtotal: 10 Enclosure Manufacturing 7. Enclosure matches the design. 1 – Dimensions and placement correlate. 8. Name of the device is attached on the enclosure. 1 9. The logo design is attached on the enclosure. 2 10. The logo design on the enclosure is durable and not merely a 2 paper pasted on the enclosure (painted/used decoupage/screen printed/sublimation printed). 11. The enclosure is manufactured from scratch/pre-cut parts. 5 Does NOT include: cardboard, paper, margarine container Does include: sheet metal, Perspex, Plexiglas, wood, glass and other raw materials, injection-moulded plastic boxes 12. Holes/Cut-outs in the enclosure are made with the appropriate 3 tools. 13. Specification plate with the learner's name, operating voltage, fuse 2 rating and additional information on the project. 14. Enclosure is neatly prepared, painted and aesthetically pleasing. 2 15. The circuit board is mounted using appropriate methods inside the 2 enclosure. (NO double-sided tape, Prestik, glue, chewing gum, masking tape, etc.) Enclosure Manufacturing Subtotal: 20 TOTAL (PART 2 = 30 marks) Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 36 DBE/PAT 2021 NSC 6. PROJECTS 6.1 Practical Project 6.1: Plug Tester The plug tester is a handy device you can build yourself and will provide you with years of good service. When installing and commissioning or when repairing plug circuits at home, it is advisable that you test your circuit before you switch it on. This is not the end however, even after you have switched on, there are so tests that are indispensable. Contrary to popular belief, it DOES make a difference when connecting alternating current supply to a plug and or light circuit. The LIVE is the current carrier and is at a higher potential than earth and neutral. It is imperative that the switch that controls any AC circuit is connected to the LIVE line. Follow this LED sequence when connecting the plug of the DIY Plug Tester to the plug being tested. In all AC installations, there is, or should be, an earth leakage protection relay. These devices are typically calibrated to trip and disconnect the supply in case of current leaking to ground through a connection it is not intended for. It is advised that the earth leakage be tested once every 6 months to ensure that it has not been damaged by lightning or power surges, which is not uncommon in a load-shedding scenario. By introducing a leakage current between LIVE and EARTH, the earth leakage can be checked. The leakage current values are determined using Ohm's law. The assumption is made that your supply voltage is 240 volts AC. To determine the leakage current complete the table below: 𝐼 𝑒𝑎𝑘𝑎𝑔𝑒 = 𝑉𝐴 𝑀𝑎𝑖𝑛𝑠/𝑅 𝑒𝑎𝑘𝑎𝑔𝑒 𝑅𝑒𝑠𝑖𝑠𝑡𝑜𝑟 RESISTOR LEAKAGE CURRENT BEING TESTED 47K 5,1 mA 24K 10 m 16K 15 mA 12K 2 mA 9K1 26,37 mA 8K2 29,26 m 10 S2 10 9 L 9 8 8 7 7 6 6 R1 D2 D3 5 5 47 k 4 1N4004 1N4004 4 3 3 2 2 c 1 1 N LED1 LED2 LED3 RED GREEN YELLOW S1 75CFF36-1-10 D1 R2 R3 R4 R5 R6 R7 R8 R9 47 k 47 k 47 k 24 k 16 k 12 k 9k1 8k2 1N4004 E PLUG TESTER CIRCUIT Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 37 DBE/PAT 2021 NSC COMPONENT LIST PART VALUE DESCRIPTION D1 1N4004 / 7 Diode D2 1N4004 / 7 Diode D3 1N4004 / 7 Diode LED1 GREEN LED5MM LED2 YELLOW LED5MM LED3 RED LED5MM R1 47k 2W Resistor R2 47k 2W Resistor R3 47k 2W Resistor R4 47k 2W Resistor R5 24K Resistor R6 16K Resistor R7 12K Resistor R8 9K1 Resistor R9 8K2 Resistor S1 75CF36-1-10 Single-deck rotary switches S2 Test button N/O push switch 4 PCB mount with M3 screw and nut 1 Solder wire 1m Cab tyre 1 3-pin plug Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 38 DBE/PAT 2021 NSC 6.2 Practical Project 6.2: Inverter 100 W 12 VDC to 230 VAC by IC 4047 – IRF540 100 W inverter circuit 12 VDC to 230 VAC with IRF540. The circuit applied IC 4047 to generate continuous wave signal and IRF540 to amplify the signal to be stepped up by the transformer. NOTE: You will need a 2–3 A centre-tapped transformer to handle/supply 100 W load. INVERTER 100 W 12 VDC TO 230 VAC BY IC 4047 – IRF540 COMPONENT LIST Diode 1N4007 VR1 100 KΩ C1 2 200 µF R2 390 KΩ C2 0,01 µF R3 330 Ω C3 0,1 µF R4 820 Ω C4 2,2 µF R5 220 Ω–330 Ω R6 220 Ω–330 Ω IC 4047 – IRF540 2 x D MOSFET (T1) IRF540 LED S2 SPST switch Supply 12 V or 12 V DC supply for testing TRANSFORMER on circuit diagram optional a smaller one can be used for testing. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 39 DBE/PAT 2021 NSC 6.3 Practical Project 6.3: Automatic LED emergency light This project consists of TWO sections 1. LED lamp circuit 2. The battery charger circuit R 15 S1 560 Ω T2 BD140 R 17 560 Ω R3 to R14 = 100 Ω LED LED LED LED LED LED LED LED LED LED LED LED R3 R4 R5 R6 R7 R8 R9 R10 R11 R12 R13 R14 TR 1 D1 230 V to 15 V IN OUT LM 317 500 mA D1 R 16 L D2 R1 1N4007 4,7 Ω ZD 1 ADJ 180 Ω Zener ZD 2 6,2 V LED 6V Zener C1 0,5 W D3 4,5 Ah 5,1 V 1000 µF 0,5 W 25 V N D4 VR1 T1 R2 4k7 1 kΩ BC548 1,2 kΩ D1 to D4 T3 1N4007 BC548 R18 1,2 kΩ AUTOMATIC LED EMERGENCY LIGHT LED lamp circuit  All are white hi-bright LEDs rated for 3 volts @ 25 mA.  The total current requirement is 12 x 25 = 300 mA.  This current has to flow through a T2 – BD140 PNP transistor.  The minimum current gain (hfe) of this transistor @ 500 mA is 50.  Hence the base current Ib requirement is Ic/hfe, 300/50 = 6 mA.  Base emitter drop of T2 at 500 mA is 0,77 volts.  With the fully charged battery at 6,9 volts terminal voltage (for cycle operation use) the voltage available across the new bias resistance is (6,9–0,77).  Hence the bias resistance is = 6,13/6 = 1 000 ohms.  As the battery drains the final terminal voltage will be 5,4 volts.  The bias resistance will be (5,4–0,77)/6 = 770 ohms. Hence 680 ohms was preferred for bias resistance with drained battery, also it will give enough brightness.  The very important information about BD140 is, as you view the pins, metal portion of the transistor facing down left is emitter centre collector and right is base. Most of the constructors make this mistake, relying on the convention that left base and right emitter. If you have made this mistake, correct it.  Once this portion is checked for reliable operation we will proceed to charger portion. Copyright reserved Please turn over

Downloaded from hlayiso.com Electrical Technology: Power Systems 40 DBE/PAT 2022 NSC The battery charger circuit  The battery requires a full terminal voltage of 6,9 V, at this point the charger should cut off.  That is the voltage across the chain ZD1, R2 and T1 should be 6,9 volts.  T1 be voltage of 0,7 volts plus drop across R2 and Zener voltage should be 6,9 V.  T1 is current = Ic/hfe.  Ic is 1,25/180 = 7 mA.  Ibe = Ic/hfe of T1, i.e. = 7/70 = 100 uA.  Drop across R2 =1,2 x,1 mA = 0,12 volts.  Hence Zener voltage = 6,9 – (0,7 + 0,12) = 6,08 the nearby preferred Zener voltage is 6,2 volts.  Say the battery voltage at full charge will be 7 volts with 6,2 volts Zener diode.  To calculate the R16 value for charging at 1/10th of the rated current of the battery 4,5 AH/10 = 450 mAH.  Transformer 9 volts AC the voltage across C1 will be 9 x 1,414 = 12,6 volts.  The drop across LM317 at 450 mA current for good regulation is 3 volts.  The drop across protective diode D5 is 0,7 volts.  The voltage available at cathode of D5 is 12,6 – (3 + 0,7) = 8,9 volts.  The battery after fair discharge will be at 6 volts.  Hence R16 = (8,9 – 7)/0,45 = 6 ohms.  The nearby standard value for operation is 5 ohms.  At the end point of battery 5,4 volts the maximum charging current can be of (8,9 – 5,4)/5 = 0,7 amps well within the higher charging limit of the battery.  With this circuit overnight the battery will get charged fully.  Overcharging is taken care and protected by T1. NOTE: All circuits MUST include an ON/OFF switch with an ON indicator and fuse protection. 7. CONCLUSION On completion of the practical assessment task learners should be able to demonstrate their understanding of the industry, enhance their knowledge, skills, values and reasoning abilities as well as establish connections to life outside the classroom and address real-world challenges. The PAT furthermore develops learners' life skills and provides opportunities for learners to engage in their own learning. Copyright reserved