SHS3 Applied Technology · Semester 2 Week 11: Electrical Systems Design

Lesson notes

Learning Objectives

Indicator: 3.5.1.LI.7 - Describe the methods of cooling transformers

By the end of the lesson, learners can:

Explain at least three reasons why transformers generate heat and why cooling is necessary for their safe and efficient operation.
Describe the four main methods of cooling transformers: air cooling, oil cooling, water cooling, and artificial cooling.
Match each cooling method to the type and size of transformer it is typically used for.
Compare the advantages and disadvantages of at least two cooling methods and justify which method is best for a given transformer size and location.
Identify signs of overheating in a transformer and state the appropriate cooling action to take.

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Curriculum details

Strand: Electrical and Electronic Technology (Strand 5)
Sub-strand: Electrical Systems Design (5.1)
Content standard: 3.5.1.CS.1 - 3.5.1.CS.1 Apply knowledge and understanding of electrical Machines 3.5.1.LO.1 Demonstrate knowledge and understanding of electrical Machines and appliances and apply the knowledge in servicing electrical appliances and circuits
Indicator: 3.5.1.LI.7 - Describe the methods of cooling transformers
Suggested placement: Semester 2, Week 11 (Week 31 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Source document note: The official curriculum document has a fault in this entry, so the curriculum text above is transcribed exactly as printed:

content standard text - p.183: prints the content-standard code as "2.4.1.CS.1"; filed under the section's own 3.5.1.CS.1
content standard text - p.183: prints the learning-outcome code as "2.4.1.LO.1"; filed under the section's own 3.5.1.LO.1
content standard text - p.183: the front page prints "Strand 4." for Electrical and Electronic Technology inside the YEAR THREE section, where Year 3's strand 4 is Wood Technology (printed pp.164 and 170); the Contents page (printed p.6) prints "STRAND 5. ELECTRICAL AND ELECTRONIC TECHNOLOGY" for Year 3 and Year 2 numbers the same strand 5, so the row is filed under strand 5
indicator text - p.183: prints the learning-indicator code as "2.4.1.LI.7"; filed under the section's own 3.5.1.LI.7
exemplars - p.183: prints the assessment code as "2.4.1.AS.7"; filed under the section's own 3.5.1.AS.7
Curriculum reference: NaCCA curriculum document, p. 183

Exemplars (from the NaCCA curriculum)

Focal Area: Methods Of Cooling Transformers
- Air cooling
- Oil cooling
- Water cooling
- Artificial Cooling Pedagogy Collaborative/ talk for learning I n mix-ability groups and with the use of the internet, task learners to:
- Come out with reasons why transformers need cooling.
- Describe the various methods of cooling transformers.
- Indicate the type of transformers involved in each case.

Assessment (3.5.1.AS.7). The document marks these depth-of-knowledge levels for this indicator: Level 1 Recall; Level 2 Skills of conceptual understanding; Level 3 Strategic reasoning.