ELE25726 Electrical Machines (Autumn 2026–Spring 2027)

• IRE12521 Electrical Circuits (10 ECTS) or IRE10725 Electrical Circuits 1 (5 ECTS) and IRE10825 Electrical Circuits 2 (5 ECTS)
• IRE13021 Engineering Physics with Electrophysics (10 ECTS) or IRE26625 Electrophysics (5 ECTS)

Fall Semester

Introduction to electromechanical energy conversion and the fundamental operating principles of electrical machines. Emphasis is placed on magnetic circuits, transformers, and DC machines, establishing the theoretical and practical foundation for AC machines, electric drive systems, and power electronic interfaces in subsequent courses.

Fall Content:

• Magnetic circuits: magnetic fields, core and air gaps, flux density, reluctance, and losses
• Electromagnetic induction and energy conversion: EMF equation, co-energy (intro)
• Transformers: single-phase/three-phase, equivalent circuits, no-load and short-circuit tests
• DC machines: construction, induced EMF, torque-speed characteristics, starting and speed control, power losses
• Laboratory work with DC machines

Spring Semester

Focus on induction machines and synchronous machines, including performance analysis, starting methods, speed control principles, and interaction with power electronic converters and the power grid.

Spring Content:

• Asynchronous (induction) machines: equivalent circuits, torque-speed characteristics, losses, and efficiency
• Starting methods: direct-on-line (DOL) starting, star-delta, autotransformer, soft starter (principles), rotor resistance
• Speed control: V/f control (principles), slip power, pole-changing
• Synchronous machines: rotating magnetic fields, EMF equation, synchronous reactance, OCC/SCC tests, magnetization curves
• Voltage regulation, power-angle characteristics, and synchronization
• V-curves, reactive power control, and basic motor and generator characteristics
• Modern machines: PMSM, BLDC, stepper/servo, and reluctance motors

Knowledge

The student has

• understanding of the physical principles behind electromagnetic energy conversion
• knowledge of magnetic circuits and the operation of transformers
• understanding of steady-state operation of DC machines and transformers, including equivalent circuits, losses, and efficiency
• knowledge of basic principles for DC machines and introductory concepts for induction machines
• knowledge of induction machines' equivalent circuits, torque-speed characteristics, and methods for starting and speed control
• knowledge of synchronous machines (generator and motor), excitation, and reactive power capacity
• introductory knowledge of permanent magnet machines and the interaction between the machine and the converter

Skills

The student can

• analyze magnetic circuits and calculate flux, induced EMF, torque, losses, and efficiency
• derive and apply equivalent circuits for transformers and DC machines
• perform basic laboratory measurements and interpret results in a professionally sound manner
• construct and use steady-state equivalent circuits for transformers and DC machines, as well as interpret simulation and test data
• calculate performance parameters such as torque, current, efficiency, power factor, and voltage regulation
• analyze operating points, characteristics, and limitations for motors and generators
• conduct laboratory tests on AC machines, process measurement data, and prepare a clear engineering report

General Competence

The student has

• the ability to apply basic knowledge of electrical machines to engineering problems and relevant applications within energy systems and electrification
• the ability to document and communicate experimental results in a clear and structured manner
• the ability to evaluate the choice of electrical machines for various applications with regard to efficiency, controllability, and impact on the power grid

• Approved laboratory exercises and reports
• Submission of group assignments

Mandatory coursework is graded as pass/fail. All coursework requirements must be approved before the student can sit for the exam.

There are two partial exams in the course, one at the end of each semester.

• Partial exam 1 (fall): Written exam, 3-hour duration, counts for 50%
• Partial exam 2 (spring): Written exam, 3-hour duration, counts for 50%

Permitted aids: Provided formula sheet and a calculator with cleared memory that cannot perform symbolic computation or communicate wirelessly.

The grading scale A-F is used for both partial exams. Both exams must be passed to receive a final grade in the course. A single overall individual grade is awarded for the course using the A-F scale.