The Gambia · 6 units · 440 guided minutes · controlled beta
Mechanical systems and maintenance: power transmission, condition evidence and safe release
This DASKEREL course develops understanding, visible reasoning and authentic evidence. It is learning support, not a national examination paper or regulated qualification.
Subject specification
Engineering, construction and technical systems: knowledge, formulae and assessment
Required knowledge strands
- design requirements, drawings, tolerances and materials
- forces, motion, energy and power transmission
- electrical, electronic, control and measurement systems
- manufacture, construction, maintenance, safety and quality
Formulae and reasoning frames
- Scale factor = drawing length ÷ actual length
- Moment M = force F × perpendicular distance d
- Stress σ = force F ÷ cross-sectional area A
- Work W = Fs and power P = W ÷ t
- Ohm’s law V = IR and electrical power P = VI
- Efficiency = useful output ÷ total input × 100%
- Factor of safety = failure load ÷ allowable working load
Assessment objectives
- understand technical principles
- apply design and calculation methods
- analyse, test, evaluate and improve a solution
Command words: sketch · calculate · select · design · test · evaluate
Practical and portfolio evidence
- controlled drawing
- calculation sheet
- simulation or supervised test
- hazard analysis
- inspection and revision record
Misconceptions explicitly tested: a component rating proves the complete system is safe · a drawing without revision or tolerance is construction-ready · replacing a failed part necessarily removes the root cause
Curriculum and examination-board control
DASKEREL core complete · examination mapping pending
The subject teaching core, formulae, practice and assessment objectives are available. A named examination board or curriculum authority, specification version, jurisdiction, language and assessment format must be verified before board-alignment is claimed.
Country and level beta mapping
The Gambia · Technical and vocational upper-secondary completion
Country-specific national, subnational or awarding-body model; the competent body and legal scope remain a beta research task.
Assessment route: The exact certificate, board, subject code, examination year and assessment format must be recorded before alignment is claimed.
Authority or board candidates
- The Gambia: competent national or subnational curriculum authority — exact legal name to be verified
- The Gambia: competent examination, qualifications or technical-award body — exact route to be verified
Academic review required: DASKEREL provides independent beta teaching and assessment support. This record does not claim government, board, university or awarding-body approval, recognition, accreditation or equivalence.
Beta subject-topic matrix (14 subjects)
Applied mathematics
Topics: number, ratio, proportion and financial arithmetic · algebra, functions, sequences and graphs · geometry, measure, trigonometry and vectors · probability, statistics, modelling and proof
Formulae/reasoning: Percentage change = (new value − original value) ÷ original value × 100% · Gradient = change in y ÷ change in x · Pythagoras: a² + b² = c² for a right-angled triangle · Trigonometry: sin θ = opposite ÷ hypotenuse; cos θ = adjacent ÷ hypotenuse; tan θ = opposite ÷ adjacent · Circle: circumference C = 2πr and area A = πr² · Mean = Σx ÷ n; probability = favourable outcomes ÷ equally likely outcomes
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Applied physics
Topics: measurement, motion, forces and momentum · work, energy, power and thermal systems · electricity, circuits, fields and electromagnetism · waves, radiation, matter and space
Formulae/reasoning: Speed v = distance s ÷ time t · Acceleration a = change in velocity Δv ÷ time Δt · Resultant force F = ma · Momentum p = mv · Work W = Fs and power P = E ÷ t · Potential difference V = IR; electrical power P = VI; energy E = Pt · Density ρ = m ÷ V; pressure p = F ÷ A · Wave speed v = fλ · Efficiency = useful output ÷ total input × 100%
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Applied chemistry
Topics: atomic structure, periodicity, bonding and properties · quantitative chemistry and chemical equations · energetics, rates, equilibrium, acids and redox · organic, analytical, materials and environmental chemistry
Formulae/reasoning: Amount n = mass m ÷ molar mass M · Concentration c = n ÷ V, with V in dm³ · Dilution c₁V₁ = c₂V₂ when solute amount is conserved · Percentage yield = actual yield ÷ theoretical yield × 100% · Atom economy = desired product formula mass ÷ total reactant formula mass × 100% · Gas amount n = gas volume ÷ molar gas volume under stated conditions · Rf = distance travelled by substance ÷ distance travelled by solvent front
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Technical drawing and CAD
Topics: design requirements, drawings, tolerances and materials · forces, motion, energy and power transmission · electrical, electronic, control and measurement systems · manufacture, construction, maintenance, safety and quality
Formulae/reasoning: Scale factor = drawing length ÷ actual length · Moment M = force F × perpendicular distance d · Stress σ = force F ÷ cross-sectional area A · Work W = Fs and power P = W ÷ t · Ohm’s law V = IR and electrical power P = VI · Efficiency = useful output ÷ total input × 100% · Factor of safety = failure load ÷ allowable working load
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Electrical and electronic systems
Topics: design requirements, drawings, tolerances and materials · forces, motion, energy and power transmission · electrical, electronic, control and measurement systems · manufacture, construction, maintenance, safety and quality
Formulae/reasoning: Scale factor = drawing length ÷ actual length · Moment M = force F × perpendicular distance d · Stress σ = force F ÷ cross-sectional area A · Work W = Fs and power P = W ÷ t · Ohm’s law V = IR and electrical power P = VI · Efficiency = useful output ÷ total input × 100% · Factor of safety = failure load ÷ allowable working load
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Mechanical systems and maintenance
Topics: design requirements, drawings, tolerances and materials · forces, motion, energy and power transmission · electrical, electronic, control and measurement systems · manufacture, construction, maintenance, safety and quality
Formulae/reasoning: Scale factor = drawing length ÷ actual length · Moment M = force F × perpendicular distance d · Stress σ = force F ÷ cross-sectional area A · Work W = Fs and power P = W ÷ t · Ohm’s law V = IR and electrical power P = VI · Efficiency = useful output ÷ total input × 100% · Factor of safety = failure load ÷ allowable working load
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Construction and civil technology
Topics: design requirements, drawings, tolerances and materials · forces, motion, energy and power transmission · electrical, electronic, control and measurement systems · manufacture, construction, maintenance, safety and quality
Formulae/reasoning: Scale factor = drawing length ÷ actual length · Moment M = force F × perpendicular distance d · Stress σ = force F ÷ cross-sectional area A · Work W = Fs and power P = W ÷ t · Ohm’s law V = IR and electrical power P = VI · Efficiency = useful output ÷ total input × 100% · Factor of safety = failure load ÷ allowable working load
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Computing and networking
Topics: data representation, hardware, operating systems and networks · algorithms, programming, testing and software design · data modelling, databases, analytics and AI evaluation · cybersecurity, privacy, accessibility and responsible systems
Formulae/reasoning: Data rate = data transferred ÷ time · Storage size = number of items × bits per item · Availability = uptime ÷ total time × 100% · Precision = true positives ÷ predicted positives · Recall = true positives ÷ actual positives · F1 = 2 × precision × recall ÷ (precision + recall) · Mean latency = total observed latency ÷ number of observations
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Business administration
Topics: stakeholders, enterprise, objectives and business models · markets, demand, supply, elasticity and economic context · operations, people, quality, finance and risk · strategy, marketing, innovation, sustainability and performance
Formulae/reasoning: Revenue = price × quantity · Profit = revenue − total cost · Market share = business sales ÷ total market sales × 100% · Percentage change = change ÷ original × 100% · Labour productivity = output ÷ labour input · Capacity utilisation = actual output ÷ maximum output × 100% · Price elasticity of demand = % change in quantity demanded ÷ % change in price
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Accounting and finance
Topics: source documents, double entry, ledgers and trial balance · adjustments, financial statements and cash flow · costing, budgeting, variance and decision support · controls, audit evidence, ethics and reporting quality
Formulae/reasoning: Assets = liabilities + owner equity · Profit = revenue − total expenses · Gross margin = gross profit ÷ revenue × 100% · Current ratio = current assets ÷ current liabilities · Receivables days = trade receivables ÷ credit revenue × period days · Contribution = selling price − variable cost · Break-even units = fixed cost ÷ contribution per unit · Simple interest I = Prt
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Agriculture and environmental technology
Topics: place, scale, space, population and development · physical processes, hazards, climate and ecosystems · resources, agriculture, cities, economies and inequality · fieldwork, maps, geospatial evidence and sustainable decisions
Formulae/reasoning: Population density = population ÷ area · Rate of change = change ÷ time · Percentage change = change ÷ original × 100% · Mean = Σx ÷ n and range = maximum − minimum · Irrigation volume = area × water depth · Gross margin = output value − specified variable costs
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Hospitality and service operations
Topics: stakeholders, enterprise, objectives and business models · markets, demand, supply, elasticity and economic context · operations, people, quality, finance and risk · strategy, marketing, innovation, sustainability and performance
Formulae/reasoning: Revenue = price × quantity · Profit = revenue − total cost · Market share = business sales ÷ total market sales × 100% · Percentage change = change ÷ original × 100% · Labour productivity = output ÷ labour input · Capacity utilisation = actual output ÷ maximum output × 100% · Price elasticity of demand = % change in quantity demanded ÷ % change in price
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Health and social-care foundations
Topics: cells, organisation, transport and bioenergetics · inheritance, variation, evolution and biotechnology · homeostasis, infection, health and populations · ecology, cycles, biodiversity and human impact
Formulae/reasoning: Magnification = image size ÷ actual size · Percentage change = change ÷ original × 100% · Rate = change in quantity ÷ time · Population density = number of organisms ÷ sampled area or volume · Risk rate = events ÷ population at risk over a stated period · Surface-area-to-volume ratio = surface area ÷ volume
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Safety, quality and project practice
Topics: questions, theory, literature and conceptual frameworks · quantitative, qualitative and mixed methods · sampling, validity, reliability, reflexivity and ethics · analysis, argument, peer review, impact and defence
Formulae/reasoning: Response rate = completed responses ÷ eligible invitations × 100% · Mean = Σx ÷ n; proportion = category count ÷ total · Effect estimate = outcome in comparison groups under a stated design · Claim strength is limited by design, measurement, sample and uncertainty
Comparison: DASKEREL beta drafted; current official specification comparison and academic review required.
Assessment and practical-requirement matrix
DASKEREL beta format: 210 minutes · 14 constructed-response tasks · 140 marks.
Timed, original constructed-response tasks using scenarios, supplied evidence, calculations or reasoned judgements; no answer-option guessing.
Task-specific criteria, transparent workings, evidence quality, limitations and justified conclusions; official grade boundaries are not inferred.
- Applied mathematics: annotated working · graph with scale and units · error analysis · alternative method · model limitation statement
- Applied physics: labelled diagram · raw and processed data · uncertainty record · graph and gradient · risk-controlled method
- Applied chemistry: equation and mole map · calculation with units · risk and waste controls · repeat measurements · conditional conclusion
- Technical drawing and CAD: controlled drawing · calculation sheet · simulation or supervised test · hazard analysis · inspection and revision record
- Electrical and electronic systems: controlled drawing · calculation sheet · simulation or supervised test · hazard analysis · inspection and revision record
- Mechanical systems and maintenance: controlled drawing · calculation sheet · simulation or supervised test · hazard analysis · inspection and revision record
- Construction and civil technology: controlled drawing · calculation sheet · simulation or supervised test · hazard analysis · inspection and revision record
- Computing and networking: versioned source or design · test table · logs · data card · security, accessibility and limitation review
- Business administration: stakeholder map · calculation table · option appraisal · sensitivity analysis · conditional recommendation
- Accounting and finance: source register · journal and ledger trail · reconciliation · statement workings · control and reviewer checklist
- Agriculture and environmental technology: annotated map · sampling plan · data table and graph · stakeholder comparison · sustainability appraisal
- Hospitality and service operations: stakeholder map · calculation table · option appraisal · sensitivity analysis · conditional recommendation
- Health and social-care foundations: method and variables · sampling rationale · raw observations · calculation and graph · ethical and uncertainty statement
- Safety, quality and project practice: protocol · source and decision log · ethical review · analysis trail · limitations and defence record
Official sources and source dates
No current official specification is recorded for this country and level. Authority identification, official URL, version, effective year and scope remain required before comparison or public alignment claims.
Evidence required for a public alignment claim
- Official authority or awarding-body name, jurisdiction and legal competence
- Current specification, programme or standard URL, publication date, version and effective examination year
- Subject-by-subject and topic-by-topic coverage matrix, including prerequisites and exclusions
- Assessment objectives, command words, paper structure, duration, marks, grading and permitted resources
- Required practicals, coursework, fieldwork, projects, oral work, prescribed texts and safety constraints
- Accessible assessment and reasonable-adjustment rules from the competent authority
- Original DASKEREL mock paper, mark scheme, moderation record and anti-guessing quality review
- Named academically competent reviewer, conflicts declaration, decision, review date and change log
Lesson record and offline copy
gambia:senior-secondary-technical:mechanical-systems-and-maintenance · Record opened 2026-10-29
- Content origin
- DASKEREL original beta
- Content owner
- DASKEREL
- Reuse rights
- Internal rights review pending
- DASKEREL internal lesson review
- Pending
- Country or level reference records
- 0
- Academic reviewer
- Not recorded; review required
- Language reviewer
- Not recorded; review required
This lesson needs a country-specific terminology and language review before local alignment is claimed.
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Six-unit course sequence
Unit 1 · Foundations and precise vocabulary
70 minutes
Build a connected foundation in mechanical systems and maintenance before attempting assessment tasks.
Study notes
- Study definitions, quantities, units, models, mechanisms and the conditions under which each relationship remains valid.
- Build a connected map of these Engineering, construction and technical systems strands: design requirements, drawings, tolerances and materials; forces, motion, energy and power transmission; electrical, electronic, control and measurement systems; manufacture, construction, maintenance, safety and quality.
- Create a glossary that defines each term in context and tests this misconception: a component rating proves the complete system is safe
- Connect the new ideas to prerequisite knowledge, then identify any gap that must be repaired before progression.
Worked application
Deconstruct the lesson’s worked model using the first strand, “design requirements, drawings, tolerances and materials”. Label every concept, assumption and decision, then explain why each step belongs to quantitative, scientific and engineering.
Guided practice
- Complete the relevant part of the guided practice for mechanical systems and maintenance; label the command word, selected strand and assessment objective, then annotate every reasoning step.
- Create a second mechanical systems and maintenance example with different data, audience or constraints, use an appropriate formula or reasoning frame, and solve it independently.
- Use the quality criteria to self-assess, obtain feedback where available, and submit a revised version with a change log.
Mastery checks
- Can you explain the central mechanical systems and maintenance idea without relying on the worked wording?
- Can you define and apply “Scale factor = drawing length ÷ actual length” or explain why a different reasoning frame is required?
- Can you detect and correct this misconception: a component rating proves the complete system is safe?
- Can you identify the evidence, assumptions, limitations and a plausible alternative?
- Can you transfer the method to a new case and justify every important choice?
Portfolio evidence: Produce a controlled maintenance-and-release pack for a simulated guarded motor-and-belt system. Include a power-flow diagram, speed-ratio, slip, efficiency and torque calculations, rating and duty comparison, condition baseline and trend table, fault tree, lubrication register, isolation and stored-energy plan, guarding and reinstatement checklist, accessible status method, measurement uncertainty, revision history and a conditional release recommendation. This desk-based task does not authorise machinery operation, dismantling, lifting or live adjustment. For this unit, retain the attempt, feedback, corrections, source record and a short reflection on the next improvement.
Unit 2 · Methods, procedures and transparent reasoning
70 minutes
Learn a repeatable mechanical systems and maintenance method and know when it is appropriate.
Study notes
- Use this discipline sequence: select a model, state assumptions, show each calculation or causal step, check units and test the result against an independent method.
- Apply these subject methods: translate the brief into measurable requirements; use drawings, calculations and simulations under version control; check tolerances, interfaces, failure modes and maintainability; separate learning evidence from authority to build, energise or operate.
- Use and define the required relationships where relevant: Scale factor = drawing length ÷ actual length; Moment M = force F × perpendicular distance d; Stress σ = force F ÷ cross-sectional area A; Work W = Fs and power P = W ÷ t; Ohm’s law V = IR and electrical power P = VI; Efficiency = useful output ÷ total input × 100%; Factor of safety = failure load ÷ allowable working load.
- Separate information supplied by the task from assumptions introduced by the learner.
- Keep units, citations, definitions, intermediate working and rejected alternatives visible so another person can audit the reasoning.
Worked application
Rework the model with one changed assumption. Select and define an appropriate relationship or reasoning frame from “Scale factor = drawing length ÷ actual length”, predict the consequence before calculating or redrafting, and reconcile the prediction with the result.
Guided practice
- Complete the relevant part of the guided practice for mechanical systems and maintenance; label the command word, selected strand and assessment objective, then annotate every reasoning step.
- Create a second mechanical systems and maintenance example with different data, audience or constraints, use an appropriate formula or reasoning frame, and solve it independently.
- Use the quality criteria to self-assess, obtain feedback where available, and submit a revised version with a change log.
Mastery checks
- Can you explain the central mechanical systems and maintenance idea without relying on the worked wording?
- Can you define and apply “Moment M = force F × perpendicular distance d” or explain why a different reasoning frame is required?
- Can you detect and correct this misconception: a drawing without revision or tolerance is construction-ready?
- Can you identify the evidence, assumptions, limitations and a plausible alternative?
- Can you transfer the method to a new case and justify every important choice?
Portfolio evidence: Produce a controlled maintenance-and-release pack for a simulated guarded motor-and-belt system. Include a power-flow diagram, speed-ratio, slip, efficiency and torque calculations, rating and duty comparison, condition baseline and trend table, fault tree, lubrication register, isolation and stored-energy plan, guarding and reinstatement checklist, accessible status method, measurement uncertainty, revision history and a conditional release recommendation. This desk-based task does not authorise machinery operation, dismantling, lifting or live adjustment. For this unit, retain the attempt, feedback, corrections, source record and a short reflection on the next improvement.
Unit 3 · Guided and independent practice
70 minutes
Move from supported examples to unfamiliar mechanical systems and maintenance problems.
Study notes
- Complete one imitative task, one task with changed data or context, and one unfamiliar transfer task.
- Practise the command words explicitly: sketch, calculate, select, design, test, evaluate.
- Check performance against these objectives: understand technical principles; apply design and calculation methods; analyse, test, evaluate and improve a solution.
- After each attempt, classify errors as knowledge, method, evidence, calculation, communication or checking errors.
- Revise the response from feedback and record exactly which change improved the evidence.
Worked application
Compare two plausible responses to the same mechanical systems and maintenance problem. Use the relevant command word and assessment objective to identify the stronger reasoning, then repair the weaker response without copying the stronger wording.
Guided practice
- Complete the relevant part of the guided practice for mechanical systems and maintenance; label the command word, selected strand and assessment objective, then annotate every reasoning step.
- Create a second mechanical systems and maintenance example with different data, audience or constraints, use an appropriate formula or reasoning frame, and solve it independently.
- Use the quality criteria to self-assess, obtain feedback where available, and submit a revised version with a change log.
Mastery checks
- Can you explain the central mechanical systems and maintenance idea without relying on the worked wording?
- Can you define and apply “Stress σ = force F ÷ cross-sectional area A” or explain why a different reasoning frame is required?
- Can you detect and correct this misconception: replacing a failed part necessarily removes the root cause?
- Can you identify the evidence, assumptions, limitations and a plausible alternative?
- Can you transfer the method to a new case and justify every important choice?
Portfolio evidence: Produce a controlled maintenance-and-release pack for a simulated guarded motor-and-belt system. Include a power-flow diagram, speed-ratio, slip, efficiency and torque calculations, rating and duty comparison, condition baseline and trend table, fault tree, lubrication register, isolation and stored-energy plan, guarding and reinstatement checklist, accessible status method, measurement uncertainty, revision history and a conditional release recommendation. This desk-based task does not authorise machinery operation, dismantling, lifting or live adjustment. For this unit, retain the attempt, feedback, corrections, source record and a short reflection on the next improvement.
Unit 4 · Applied case and decision-making
70 minutes
Apply mechanical systems and maintenance to a realistic but controlled context.
Study notes
- Use a safe community, laboratory, environmental or technical decision using supplied or simulated evidence.
- Produce appropriate practical or source evidence: controlled drawing; calculation sheet; simulation or supervised test; hazard analysis; inspection and revision record.
- Map stakeholders, constraints, benefits, risks and information that remains missing.
- Judge the result using accuracy, dimensional consistency, uncertainty, repeatability, safety and a conclusion that does not exceed the evidence.
Worked application
Prepare a decision table with at least two defensible options, weighted or reasoned criteria, a sensitivity check and a conditional recommendation grounded in “controlled drawing”.
Guided practice
- Complete the relevant part of the guided practice for mechanical systems and maintenance; label the command word, selected strand and assessment objective, then annotate every reasoning step.
- Create a second mechanical systems and maintenance example with different data, audience or constraints, use an appropriate formula or reasoning frame, and solve it independently.
- Use the quality criteria to self-assess, obtain feedback where available, and submit a revised version with a change log.
Mastery checks
- Can you explain the central mechanical systems and maintenance idea without relying on the worked wording?
- Can you define and apply “Work W = Fs and power P = W ÷ t” or explain why a different reasoning frame is required?
- Can you detect and correct this misconception: a component rating proves the complete system is safe?
- Can you identify the evidence, assumptions, limitations and a plausible alternative?
- Can you transfer the method to a new case and justify every important choice?
Portfolio evidence: Produce a controlled maintenance-and-release pack for a simulated guarded motor-and-belt system. Include a power-flow diagram, speed-ratio, slip, efficiency and torque calculations, rating and duty comparison, condition baseline and trend table, fault tree, lubrication register, isolation and stored-energy plan, guarding and reinstatement checklist, accessible status method, measurement uncertainty, revision history and a conditional release recommendation. This desk-based task does not authorise machinery operation, dismantling, lifting or live adjustment. For this unit, retain the attempt, feedback, corrections, source record and a short reflection on the next improvement.
Unit 5 · Evidence, challenge and quality assurance
70 minutes
Test whether a mechanical systems and maintenance conclusion survives scrutiny.
Study notes
- Use measurements, datasets, diagrams, calculations, observations, uncertainty ranges and reproducible records.
- Actively test these known misconceptions: a component rating proves the complete system is safe; a drawing without revision or tolerance is construction-ready; replacing a failed part necessarily removes the root cause.
- Distinguish observation, source statement, inference, calculation, value judgement and authorised decision.
- Challenge the conclusion with the strongest alternative explanation and state what new evidence could overturn it.
Worked application
Audit a deliberately flawed response that includes “a drawing without revision or tolerance is construction-ready”, a source problem, a hidden assumption, a method error and an overconfident conclusion; correct each fault and document its effect.
Guided practice
- Complete the relevant part of the guided practice for mechanical systems and maintenance; label the command word, selected strand and assessment objective, then annotate every reasoning step.
- Create a second mechanical systems and maintenance example with different data, audience or constraints, use an appropriate formula or reasoning frame, and solve it independently.
- Use the quality criteria to self-assess, obtain feedback where available, and submit a revised version with a change log.
Mastery checks
- Can you explain the central mechanical systems and maintenance idea without relying on the worked wording?
- Can you define and apply “Ohm’s law V = IR and electrical power P = VI” or explain why a different reasoning frame is required?
- Can you detect and correct this misconception: a drawing without revision or tolerance is construction-ready?
- Can you identify the evidence, assumptions, limitations and a plausible alternative?
- Can you transfer the method to a new case and justify every important choice?
Portfolio evidence: Produce a controlled maintenance-and-release pack for a simulated guarded motor-and-belt system. Include a power-flow diagram, speed-ratio, slip, efficiency and torque calculations, rating and duty comparison, condition baseline and trend table, fault tree, lubrication register, isolation and stored-energy plan, guarding and reinstatement checklist, accessible status method, measurement uncertainty, revision history and a conditional release recommendation. This desk-based task does not authorise machinery operation, dismantling, lifting or live adjustment. For this unit, retain the attempt, feedback, corrections, source record and a short reflection on the next improvement.
Unit 6 · Synthesis, portfolio and progression
90 minutes
Demonstrate durable mechanical systems and maintenance mastery through an original artefact.
Study notes
- Plan an artefact for a named audience and assessment purpose, with milestones for research, first attempt, feedback, revision and final verification.
- Show coverage of all four subject strands: design requirements, drawings, tolerances and materials; forces, motion, energy and power transmission; electrical, electronic, control and measurement systems; manufacture, construction, maintenance, safety and quality.
- Include a concise explanation for a non-specialist and a technical appendix that preserves the full reasoning.
- Apply this boundary before release: Real experiments, clinical decisions, construction, energised systems, machinery and environmental interventions require competent supervision and local authority.
Worked application
Defend the final recommendation against two questions using “analyse, test, evaluate and improve a solution”, acknowledge one genuine limitation and identify the next learning step rather than claiming complete certainty.
Guided practice
- Complete the relevant part of the guided practice for mechanical systems and maintenance; label the command word, selected strand and assessment objective, then annotate every reasoning step.
- Create a second mechanical systems and maintenance example with different data, audience or constraints, use an appropriate formula or reasoning frame, and solve it independently.
- Use the quality criteria to self-assess, obtain feedback where available, and submit a revised version with a change log.
Mastery checks
- Can you explain the central mechanical systems and maintenance idea without relying on the worked wording?
- Can you define and apply “Efficiency = useful output ÷ total input × 100%” or explain why a different reasoning frame is required?
- Can you detect and correct this misconception: replacing a failed part necessarily removes the root cause?
- Can you identify the evidence, assumptions, limitations and a plausible alternative?
- Can you transfer the method to a new case and justify every important choice?
Portfolio evidence: Produce a controlled maintenance-and-release pack for a simulated guarded motor-and-belt system. Include a power-flow diagram, speed-ratio, slip, efficiency and torque calculations, rating and duty comparison, condition baseline and trend table, fault tree, lubrication register, isolation and stored-energy plan, guarding and reinstatement checklist, accessible status method, measurement uncertainty, revision history and a conditional release recommendation. This desk-based task does not authorise machinery operation, dismantling, lifting or live adjustment. For this unit, retain the attempt, feedback, corrections, source record and a short reflection on the next improvement.
Topic-by-topic teaching chapters
Subject chapter
Chapter 1 · design requirements, drawings, tolerances and materials
Teaching explanation
- Define the key ideas inside “design requirements, drawings, tolerances and materials”, give an example and a non-example, and connect them to the previous chapter rather than learning isolated vocabulary.
- Use this subject method: translate the brief into measurable requirements. Explain why it is appropriate, which assumptions it introduces and which evidence would show that it has failed.
- Apply “Drawing scale = representation length ÷ actual length in matching units”. Define every term, preserve units or authority, and interpret the result in the original mechanical systems and maintenance context.
- Produce controlled drawing, then separate raw evidence, processing, inference and judgement so another learner can audit the conclusion.
- Test and correct this misconception: a component rating proves the complete system is safe
Formula or reasoning frame
Drawing scale = representation length ÷ actual length in matching units
Worked solution
- Supplied mechanical systems and maintenance case for “design requirements, drawings, tolerances and materials”: A fictional drawing uses 4 cm to represent an actual 2 m component. Find the drawing scale.
- Select the matching frame, “Drawing scale = representation length ÷ actual length in matching units”, and identify the exact quantities or textual details provided by the case before applying it.
- State the condition that makes this frame relevant, including the unit, population, source or decision boundary where applicable; do not supply missing facts as if they were observed.
- Worked solution: 2 m = 200 cm, so 4:200 simplifies to 1:50. Check the stated dimension and tolerance before any real manufacture.
- Check the method against “a component rating proves the complete system is safe”; explain which supplied fact supports the conclusion and which further evidence would be needed to generalise it.
Foundation practice
- Reproduce the worked solution for “design requirements, drawings, tolerances and materials” with all intermediate steps and units or stated assumptions; then explain one step in your own words.
- Identify which fact in the supplied case is an observation, which is a calculation, and which is a limited interpretation.
Standard practice
- Independent parallel case: A drawing uses 3 cm for an actual 1.5 m component. Find the scale.
- Explain why “Drawing scale = representation length ÷ actual length in matching units” fits this supplied case, and identify one assumption or boundary of the result.
Stretch and transfer
- Compare the worked and independent cases. Change one supplied input or condition, predict the direction of change, and check whether the relationship “Drawing scale = representation length ÷ actual length in matching units” still applies.
- Explain which additional controlled drawing would be required before transferring this result to a real mechanical systems and maintenance decision.
Open chapter answer and marking guidance after attempting the tasks
- Worked-case answer and reasoning: 2 m = 200 cm, so 4:200 simplifies to 1:50. Check the stated dimension and tolerance before any real manufacture.
- Independent-case answer and reasoning: 1.5 m = 150 cm; 3:150 = 1:50. Keep drawing and actual lengths in the same unit.
- Foundation practice must preserve the supplied values, show intermediate reasoning and distinguish the stated data from the interpretation.
- For stretch practice, a correct prediction must name the changed input, hold the other assumptions fixed, recalculate or re-evaluate the result, and state why a different condition might invalidate the frame.
Subject chapter
Chapter 2 · forces, motion, energy and power transmission
Teaching explanation
- Define the key ideas inside “forces, motion, energy and power transmission”, give an example and a non-example, and connect them to the previous chapter rather than learning isolated vocabulary.
- Use this subject method: use drawings, calculations and simulations under version control. Explain why it is appropriate, which assumptions it introduces and which evidence would show that it has failed.
- Apply “Moment = force × perpendicular distance from pivot”. Define every term, preserve units or authority, and interpret the result in the original mechanical systems and maintenance context.
- Produce calculation sheet, then separate raw evidence, processing, inference and judgement so another learner can audit the conclusion.
- Test and correct this misconception: a drawing without revision or tolerance is construction-ready
Formula or reasoning frame
Moment = force × perpendicular distance from pivot
Worked solution
- Supplied mechanical systems and maintenance case for “forces, motion, energy and power transmission”: In a desk-based model, a 50 N force acts 0.4 m perpendicular to a pivot. Find the moment.
- Select the matching frame, “Moment = force × perpendicular distance from pivot”, and identify the exact quantities or textual details provided by the case before applying it.
- State the condition that makes this frame relevant, including the unit, population, source or decision boundary where applicable; do not supply missing facts as if they were observed.
- Worked solution: Moment = force × perpendicular distance = 50 × 0.4 = 20 N·m. The result does not establish that a real structure is safe.
- Check the method against “a drawing without revision or tolerance is construction-ready”; explain which supplied fact supports the conclusion and which further evidence would be needed to generalise it.
Foundation practice
- Reproduce the worked solution for “forces, motion, energy and power transmission” with all intermediate steps and units or stated assumptions; then explain one step in your own words.
- Identify which fact in the supplied case is an observation, which is a calculation, and which is a limited interpretation.
Standard practice
- Independent parallel case: An 80 N force acts 0.25 m perpendicular to a model pivot. Find the moment.
- Explain why “Moment = force × perpendicular distance from pivot” fits this supplied case, and identify one assumption or boundary of the result.
Stretch and transfer
- Compare the worked and independent cases. Change one supplied input or condition, predict the direction of change, and check whether the relationship “Moment = force × perpendicular distance from pivot” still applies.
- Explain which additional calculation sheet would be required before transferring this result to a real mechanical systems and maintenance decision.
Open chapter answer and marking guidance after attempting the tasks
- Worked-case answer and reasoning: Moment = force × perpendicular distance = 50 × 0.4 = 20 N·m. The result does not establish that a real structure is safe.
- Independent-case answer and reasoning: 80 × 0.25 = 20 N·m. The perpendicular distance, not an arbitrary arm length, belongs in the formula.
- Foundation practice must preserve the supplied values, show intermediate reasoning and distinguish the stated data from the interpretation.
- For stretch practice, a correct prediction must name the changed input, hold the other assumptions fixed, recalculate or re-evaluate the result, and state why a different condition might invalidate the frame.
Subject chapter
Chapter 3 · electrical, electronic, control and measurement systems
Teaching explanation
- Define the key ideas inside “electrical, electronic, control and measurement systems”, give an example and a non-example, and connect them to the previous chapter rather than learning isolated vocabulary.
- Use this subject method: check tolerances, interfaces, failure modes and maintainability. Explain why it is appropriate, which assumptions it introduces and which evidence would show that it has failed.
- Apply “Idealised current I = V ÷ R; power P = VI”. Define every term, preserve units or authority, and interpret the result in the original mechanical systems and maintenance context.
- Produce simulation or supervised test, then separate raw evidence, processing, inference and judgement so another learner can audit the conclusion.
- Test and correct this misconception: replacing a failed part necessarily removes the root cause
Formula or reasoning frame
Idealised current I = V ÷ R; power P = VI
Worked solution
- Supplied mechanical systems and maintenance case for “electrical, electronic, control and measurement systems”: An idealised 4 Ω resistor has 12 V across it. Calculate current and electrical power on paper.
- Select the matching frame, “Idealised current I = V ÷ R; power P = VI”, and identify the exact quantities or textual details provided by the case before applying it.
- State the condition that makes this frame relevant, including the unit, population, source or decision boundary where applicable; do not supply missing facts as if they were observed.
- Worked solution: I = V ÷ R = 12 ÷ 4 = 3 A; P = VI = 12 × 3 = 36 W. Real component ratings and energised work require competent supervision.
- Check the method against “replacing a failed part necessarily removes the root cause”; explain which supplied fact supports the conclusion and which further evidence would be needed to generalise it.
Foundation practice
- Reproduce the worked solution for “electrical, electronic, control and measurement systems” with all intermediate steps and units or stated assumptions; then explain one step in your own words.
- Identify which fact in the supplied case is an observation, which is a calculation, and which is a limited interpretation.
Standard practice
- Independent parallel case: An idealised 3 Ω resistor has 9 V across it. Find current and power.
- Explain why “Idealised current I = V ÷ R; power P = VI” fits this supplied case, and identify one assumption or boundary of the result.
Stretch and transfer
- Compare the worked and independent cases. Change one supplied input or condition, predict the direction of change, and check whether the relationship “Idealised current I = V ÷ R; power P = VI” still applies.
- Explain which additional simulation or supervised test would be required before transferring this result to a real mechanical systems and maintenance decision.
Open chapter answer and marking guidance after attempting the tasks
- Worked-case answer and reasoning: I = V ÷ R = 12 ÷ 4 = 3 A; P = VI = 12 × 3 = 36 W. Real component ratings and energised work require competent supervision.
- Independent-case answer and reasoning: I = 9 ÷ 3 = 3 A; P = 9 × 3 = 27 W. This desk calculation does not authorise a physical circuit build.
- Foundation practice must preserve the supplied values, show intermediate reasoning and distinguish the stated data from the interpretation.
- For stretch practice, a correct prediction must name the changed input, hold the other assumptions fixed, recalculate or re-evaluate the result, and state why a different condition might invalidate the frame.
Subject chapter
Chapter 4 · manufacture, construction, maintenance, safety and quality
Teaching explanation
- Define the key ideas inside “manufacture, construction, maintenance, safety and quality”, give an example and a non-example, and connect them to the previous chapter rather than learning isolated vocabulary.
- Use this subject method: separate learning evidence from authority to build, energise or operate. Explain why it is appropriate, which assumptions it introduces and which evidence would show that it has failed.
- Apply “Efficiency = useful output ÷ total input × 100%”. Define every term, preserve units or authority, and interpret the result in the original mechanical systems and maintenance context.
- Produce hazard analysis, then separate raw evidence, processing, inference and judgement so another learner can audit the conclusion.
- Test and correct this misconception: a component rating proves the complete system is safe
Formula or reasoning frame
Efficiency = useful output ÷ total input × 100%
Worked solution
- Supplied mechanical systems and maintenance case for “manufacture, construction, maintenance, safety and quality”: A fictional system takes 50 J input and delivers 40 J useful output. Find its stated efficiency.
- Select the matching frame, “Efficiency = useful output ÷ total input × 100%”, and identify the exact quantities or textual details provided by the case before applying it.
- State the condition that makes this frame relevant, including the unit, population, source or decision boundary where applicable; do not supply missing facts as if they were observed.
- Worked solution: Efficiency = 40 ÷ 50 × 100 = 80%. The missing 10 J is not enough information to specify a loss mechanism or approve a design.
- Check the method against “a component rating proves the complete system is safe”; explain which supplied fact supports the conclusion and which further evidence would be needed to generalise it.
Foundation practice
- Reproduce the worked solution for “manufacture, construction, maintenance, safety and quality” with all intermediate steps and units or stated assumptions; then explain one step in your own words.
- Identify which fact in the supplied case is an observation, which is a calculation, and which is a limited interpretation.
Standard practice
- Independent parallel case: A fictional system takes 75 J input and delivers 60 J useful output. Find efficiency.
- Explain why “Efficiency = useful output ÷ total input × 100%” fits this supplied case, and identify one assumption or boundary of the result.
Stretch and transfer
- Compare the worked and independent cases. Change one supplied input or condition, predict the direction of change, and check whether the relationship “Efficiency = useful output ÷ total input × 100%” still applies.
- Explain which additional hazard analysis would be required before transferring this result to a real mechanical systems and maintenance decision.
Open chapter answer and marking guidance after attempting the tasks
- Worked-case answer and reasoning: Efficiency = 40 ÷ 50 × 100 = 80%. The missing 10 J is not enough information to specify a loss mechanism or approve a design.
- Independent-case answer and reasoning: 60 ÷ 75 × 100 = 80%. Equal efficiency does not imply equal power, reliability or safety.
- Foundation practice must preserve the supplied values, show intermediate reasoning and distinguish the stated data from the interpretation.
- For stretch practice, a correct prediction must name the changed input, hold the other assumptions fixed, recalculate or re-evaluate the result, and state why a different condition might invalidate the frame.
Prerequisites
- 1. Use SI units and rearrange relationships involving force, torque, speed, power, efficiency, pressure and mechanical advantage.
- 2. Interpret a simple assembly drawing, identify common fasteners, bearings, shafts, gears, belts, chains and guards, and distinguish a component from a system.
- 3. Record measurements with units, tolerances and instrument resolution rather than treating an observed value as exact.
- 4. Prepare an accessible method for documenting hazards, isolation points, symptoms, tests, findings, revisions and competent approvals.
Learning objectives
- 1. Explain how force, torque, speed and power move through shafts, gears, belt, chain, bearing and coupling systems.
- 2. Calculate speed ratio, transmitted torque, mechanical power, efficiency and service limits from stated evidence.
- 3. Select condition-monitoring evidence and distinguish a symptom from a verified failure mode and root cause.
- 4. Plan preventive and condition-based maintenance with controlled lubrication, alignment, fastening and inspection records.
- 5. Produce an auditable maintenance-and-release record that preserves isolation, guarding, measurement uncertainty and competent approval.
Deep explanation
- 1. A mechanical system transfers or transforms force and motion. A free-body diagram identifies applied forces, reactions and moments, while a power-flow diagram follows energy from prime mover to useful output and losses. A component may be individually rated yet unsuitable when alignment, duty cycle, shock loading, environment or adjoining parts are ignored.
- 2. Torque is the turning effect of a force, T = Fr for a perpendicular force at radius r. Rotational power is P = Tω, where angular speed ω = 2πn/60 for n revolutions per minute. These relationships require coherent units and describe an operating point; they do not prove that a shaft, key, coupling or guard is safe.
- 3. A gear-pair speed ratio changes speed and torque according to tooth count, subject to losses. For an ideal external pair, output speed equals input speed multiplied by driver teeth divided by driven teeth. Belt and chain ratios use effective pulley or sprocket diameters or tooth counts, but slip, wear, tension and efficiency make measured results differ from the ideal model.
- 4. Mechanical efficiency is useful output power divided by input power. Losses appear as heat, vibration, noise, deformation and friction. Efficiency cannot exceed 100%, and an implausible result should trigger checks of units, instrument calibration, simultaneous measurements and system boundaries rather than being rounded into acceptability.
- 5. Bearings support and locate moving parts while controlling friction. Lubricant type, viscosity, quantity, cleanliness and interval must follow controlled evidence: both starvation and over-lubrication can raise temperature and damage seals. Mixing incompatible lubricants or applying lubricant to an unidentified point creates risk rather than maintenance.
- 6. Condition monitoring compares repeatable evidence over time. Temperature, vibration, noise, oil condition, backlash, belt tension and alignment can reveal change, but a single high reading is not automatically a diagnosis. Baseline, load, speed, sensor location, uncertainty and alarm criteria must be recorded before a trend is interpreted.
- 7. A fault-finding process moves from symptom to evidence, hypotheses, discriminating tests and verified cause. Replacing the failed part without examining contamination, misalignment, overload, looseness or lubrication may restore operation briefly while leaving the root cause active. Every intervention changes the evidence and must be recorded.
- 8. Maintenance strategies include corrective, preventive and condition-based work. A defensible plan ranks consequence, likelihood, detectability, statutory or manufacturer requirements, access time and spare-part constraints. Calendar frequency alone is not proof that a task is useful, and a risk ranking does not authorise work outside competence.
- 9. Rotating machinery, stored mechanical energy, raised loads, pressure, heat and sharp or moving parts can cause serious harm. Practical work requires competent supervision, verified isolation and dissipation, lockout or equivalent control, guarding, suitable tools, safe lifting, reinstatement checks and local legal compliance. This lesson authorises desk-based analysis and controlled evidence only.
Worked model
- 1. A 1.50 kW motor runs at 1440 r/min and drives a shaft through a 120 mm driver pulley and a 300 mm driven pulley. Ignoring slip initially, shaft speed is 1440 × 120/300 = 576 r/min.
- 2. The drive efficiency is measured as 88.0%, so useful shaft power is 1.50 × 0.880 = 1.32 kW. Angular speed is 2π × 576/60 = 60.3 rad s⁻¹.
- 3. Output torque is P/ω = 1320/60.3 = 21.9 N m. If a measured output speed is 552 r/min, slip relative to the ideal speed is (576 − 552)/576 × 100 = 4.17%.
- 4. The maintenance record sets a competent-reviewed continuous torque limit of 20.0 N m for the complete guarded assembly. The calculated 21.9 N m exceeds that limit, so the proposed operating point is not releasable even though the motor and belt each have separate ratings.
- 5. Before any supervised trial, the pack must reconcile pulley sizes, belt specification and tension, alignment, guard and fastener status, measured speed method, efficiency evidence, load duty and the 20.0 N m limit. Isolation and zero-energy verification remain mandatory before inspection or adjustment.
Guided practice
- 1. Calculate speed, angular speed, power and torque for three gear, belt or chain drives, state idealising assumptions and compare the result with one stated service limit.
- 2. Use repeated temperature or vibration readings to distinguish normal scatter, a developing trend and an alarm, including baseline, load, location and measurement uncertainty.
- 3. Build a lubrication register containing component, approved lubricant, quantity, interval, contamination control, application method and evidence of completion.
- 4. Create a fault tree for a hot bearing and design tests that distinguish overload, misalignment, looseness, contamination, lubricant error and sensor error.
- 5. Develop a preventive and condition-based maintenance plan using consequence, likelihood, detectability, manufacturer evidence and competent-review gates.
- 6. Audit a maintenance proposal containing planted defects: no isolation, removed guard, suspended load, mixed lubricant, undocumented pulley change and a colour-only condition chart.
Understanding and misconception checks
- 1. Why can output torque increase when rotational speed decreases even though useful power also falls through losses?
- 2. How do slip, efficiency and instrument uncertainty change an ideal belt-drive calculation?
- 3. Why is one vibration or temperature reading insufficient to identify a root cause?
- 4. How can over-lubrication create a failure even when the lubricant grade is correct?
- 5. Why must a replacement component be checked against the complete assembly, duty and guarding rather than its catalogue rating alone?
- 6. Which conditions require work to stop and be referred to competent maintenance, lifting, pressure or machinery-safety personnel?
Review and progression
- 1. After 24 hours, repeat the speed, slip and torque calculation with changed pulley sizes and efficiency without consulting the worked model.
- 2. After one week, diagnose a new simulated bearing-temperature trend from incomplete evidence and specify the safest discriminating tests and stop criteria.
- 3. Add the checked calculations, maintenance plan, condition record, feedback and revision history to the DASKEREL portfolio without unnecessary personal or sensitive data.
Accessibility and equivalent evidence
- 1. Every assembly, power-flow and isolation diagram has a structured text alternative identifying components, connections, motion, energy and hazards.
- 2. Trend charts use labels, symbols and numerical tables as well as colour; alarms have visual, audible or tactile equivalents appropriate to the context.
- 3. Learners may use enlarged drawings, tactile diagrams, keyboard-operable simulation, structured calculation tables or dictated reasoning with a transcript when the same criteria are demonstrated.
- 4. Demonstration media require captions, audio description, transcript and a non-video procedure, while practical evidence remains subject to identical competence, isolation and safeguarding controls.
Evidence task
Produce a controlled maintenance-and-release pack for a simulated guarded motor-and-belt system. Include a power-flow diagram, speed-ratio, slip, efficiency and torque calculations, rating and duty comparison, condition baseline and trend table, fault tree, lubrication register, isolation and stored-energy plan, guarding and reinstatement checklist, accessible status method, measurement uncertainty, revision history and a conditional release recommendation. This desk-based task does not authorise machinery operation, dismantling, lifting or live adjustment.
Record sources, assistance received, feedback and revisions. Do not include unnecessary personal or sensitive information.