ENEL481-20S2 (C) Semester Two 2020

Electrical Machines

15 points

Start Date: Monday, 13 July 2020
End Date: Sunday, 8 November 2020
Withdrawal Dates
Last Day to withdraw from this course:
  • Without financial penalty (full fee refund): Friday, 24 July 2020
  • Without academic penalty (including no fee refund): Friday, 25 September 2020


Unified electroheater and transformer design; power transformer assessment and industry standard high voltage testing of generators, transformers and cables. Rotating Machines.

This course teaches material in two main areas.

Firstly, students will learn about condition assessment of electric machines in the electric power industry. We will cover industry standard high voltage testing, which is necessary when: buying new equipment, uprating existing equipment or performing investigations. These tests are applicable to generators, motors, cables and transformers.

Secondly, unified electroheater and power transformer design as applicable to dc and mains frequency applications will be covered. Students will learn about, properties of materials often used in electroheater and transformer design, thermal fundamentals, skin effect, and conventional and reverse methods for induction heating and transformer design.

Proposed teaching/delivery methods:

Students will learn through lecture hours, assignments, group work and laboratory sessions.
Lecture hours will cover the following topics, supported by private study.

High Voltage Testing:
• Electrical safety standards
• High voltage withstand testing – AC, DC, VLF
• Impulse testing
• Partial discharge
• Insulation Power Factor and Capacitance

Rotating Machines:
• Insulation coordination of stator coils
• Stator failure modes
• Ring flux testing
• Rotor tests

• Transformer construction
• Factory acceptance testing
• Two winding transformer insulation model
• Transformer oil testing and DGA

Induction Heater Design:
• Electric heating
• Properties of materials
• Thermal fundamentals
• DC and AC conduction heating
• Induction heating and the transformer model of an induction heater
• Transduction heating

Transformer Design:
• Full core transformer design
• Reverse design method for full core transformers
• Partial core transformers
• Partial core resonant transformers
• Finite element method

Two laboratory exercises applying industry standard high voltage test techniques to real equipment.

A design assignment for an electroheater of transformer

Learning Outcomes

  • Learning Outcomes and National Qualifications Framework (NQF)

    Knowledge outcomes:
  • Solid grasp of material properties as they apply to the design of elctroheaters and power transformers.
  • Knowledge of the relationship between the design variables; current density, electric fields, flux density, weight etc.; and how their interaction effects the design performance.
  • Understanding of the appropriate testing methodologies for assessing the quality and performance of electrical insulation systems.
  • Fundamental knowledge of industry-standard test procedures and electrical safety practices.

    Skills outcomes:
  • Ability to choose appropriate materials for electrical machine design.
  • Ability to design an electroheater or transformer from the above material choices.
  • Ability to estimate the performance of the electroheater or transformer design.
  • Ability to perform high voltage testing in a safe manner to industry standards.
  • Ability to analyze incipient faults in power transformer equipment through DGA

    Personal attributes developed:
  • Communicating complex concepts to peers
  • Designing and constructing optimal systems with limited resources


ENEL381, ENEL382



Timetable 2020

Students must attend one activity from each section.

Lecture A
Activity Day Time Location Weeks
01 Thursday 11:00 - 12:00 Beatrice Tinsley 111 13 Jul - 23 Aug
7 Sep - 18 Oct
Lecture B
Activity Day Time Location Weeks
01 Wednesday 14:00 - 15:00 Link 309 Lecture Theatre 13 Jul - 23 Aug
7 Sep - 18 Oct
Lecture C
Activity Day Time Location Weeks
01 Monday 10:00 - 11:00 Beatrice Tinsley 112 13 Jul - 23 Aug
7 Sep - 18 Oct
Lab A
Activity Day Time Location Weeks
01 Tuesday 14:00 - 17:00 High Tension Lab 101 13 Jul - 23 Aug

Course Coordinator

Andrew Lapthorn


Assessment Due Date Percentage 
Assignment 1 30%
Assignment 2 30%
Exam 40%

Indicative Fees

Domestic fee $1,102.00

International fee $5,500.00

* Fees include New Zealand GST and do not include any programme level discount or additional course related expenses.

For further information see Electrical and Computer Engineering.

All ENEL481 Occurrences

  • ENEL481-20S2 (C) Semester Two 2020