LessonnotesGH

SHS3 Applied Technology · Semester 2, Week 10

Electrical Systems Design

Lesson notes

Learning Objectives

Indicator: 3.5.1.LI.6 - Explain losses that occur in a transformer and how they affect the performance of the transformer

By the end of the lesson, learners can:

  1. Identify and describe the main types of losses that occur in a transformer (copper losses, iron or core losses, and stray losses).
  2. Explain the causes of each type of transformer loss in simple terms.
  3. Describe how each loss affects the performance of a transformer, including its efficiency, temperature rise, and output voltage.
  4. Calculate the efficiency of a transformer given the input power and output power (or the total losses).
  5. Discuss at least two practical ways to reduce transformer losses based on their understanding of what causes them.

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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.6 - Explain losses that occur in a transformer and how they affect the performance of the transformer
Suggested placement
Semester 2, Week 10 (Week 30 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.182: 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.182: 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.182: 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.182: prints the learning-indicator code as "2.4.1.LI.6"; filed under the section's own 3.5.1.LI.6
  • exemplars - p.182: prints the assessment code as "2.4.1.AS.6"; filed under the section's own 3.5.1.AS.6
Curriculum reference
NaCCA curriculum document, p. 182

Exemplars (from the NaCCA curriculum) 

Focal Area: Losses and Efficiency Transformers
1. Losses in a transformer
2. Efficiency of transformer Pedagogy
Research/ Collaborative Learning: In mixed-ability groups, guide learners to:
- Explain the losses that occur in a transformer eg Core losses, Bearing friction loss, etc
- Explain the effect of these losses on the transformer performance Critical Thinking In mixed-ability groups, guide learners to calculate for efficiency of transformer.

Assessment (3.5.1.AS.6). The document marks these depth-of-knowledge levels for this indicator: Level 1 Recall; Level 2 Skills of conceptual understanding; Level 3 Strategic reasoning; Level 4 Extended critical thinking and reasoning.
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