The course "Electric Machines II" aims to give students the necessary knowledge on AC electric motors. More specifically, it refers to the structure, operation, special features and applications of different types of AC motors.

Upon successful conclusion of this course, the students will be able to:

1. describe and explain the structure, structural characteristics and basic design principles of AC machines, 
2. to experimentally determine and numerically calculate the parameters of the equivalent circuit of each machine, 
3. examine and analyze the operation of AC motors through the corresponding equivalent circuits,
4. identify and distinguish the different types and variants of AC motors,
5. to create and reconstruct corresponding wiring connections of AC motors in the laboratory,
6. compare the alternatives and suggest the appropriate AC motor for a given application.

• Search, analysis and synthesis of data and information, using the necessary technologies
• Adaptation to new situations 
• Autonomous work
• Teamwork
• Work in an interdisciplinary environment 
• Production of new research ideas

Theoretical Lecture Units

• General: Creation of a rotating magnetic field.
• Synchronous machines: Structure, principle of operation, characteristics, types, excitation, equivalent circuits, vector equation - vector diagram, power flow diagram, losses and efficiency. Experimental determination of equivalent circuit parameters. Study of a synchronous machine for motor/generator operation. For generator operation: Autonomous operation - synchronization, behavior in changes of load and excitation current, specifications. For motor operation: Starting, behavior in changes of load and excitation current.
• Three phase asynchronous motors: Structure, structural characteristics, types (squirrel cage, wound rotor), principle of operation, concept of slip, equivalent circuit, vector equation - vector diagram, power flow diagram, losses and efficiency, torque-speed characteristic, changes on the characteristic.
• Single phase asynchronous motor: Structure and principle of operation, equivalent circuit, starting.
• Reference to special types of motors (Universal, Synchronous reluctance, Switched reluctance).

Laboratory Exercises

1. Study of synchronous AC machines.
2. Study of parallel operation of alternators and synchronous motor loading.
3. Starting of three-phase asynchronous motors, of squirrel cage and slip-ring type.
4. Study of power balance and loading of an asynchronous squirrel cage motor.
5. Study of single-phase asynchronous motor.

- Suggested bibliography:

• Stephen Chapman, 'AC-DC Electric Machines'
• Hubert I. Charles,'Electric Machines': Theory, Operation, Applications, Adjustment, and Control

- Relevant scientific journals:

• IEEE Transactions on Energy Conversion
• IEEE Transactions on Industry applications
• IET Electric Power Applications