B028297 - ELECTRICAL MACHINES

Italian

1) Analysis of two-phase and three-phase circuits;
2) Single-phase and three-phase transformers;
3) Synchronous machines;
4) Asynchronous machines;
5) Direct-current machines.

1) A.E. Fitzgerald, C. Kingsley, and A. Kusko, " Electric Machinery", New
York: McGraw-Hill Book Company, 1971.
2) L.W. Matsch and J.D. Morgan: Electromagnetic and Electromechanical
Machines, New York: John Wiley & Sons, 1987.
3) S. Crepaz, "Macchine Elettriche", CittàStudi, 1997

Knowledge and ability to understand:
1) Electromagnetism laws, AC single-phase, two-phase and three-phase
circuits and DC circuits both in transient and steady-state behavior.
2) Operating principles, electromagnetic and mechanical behaviors of the
main static and rotating electrical machines: transformers, AC motors
and generators, DC motors and generators.
3) Methods to test the electrical machines.
Ability to apply knowledge in order to derive the mathematical models of
the electrical machines in the different operating conditions.
Ability to apply knowledge in order to define the equivalent circuits
parameters and the operating conditions of the electrical machines.
Ability to apply knowledge in order to select the electrical machines for
different applications on the basis of the electrical requirements.

High skills with Electrotechnics, Physics and Electromagnetism.
Good understanding of steady-state and transient analysis techniques of
single-phase and three-phase circuits.

Lectures supported by projector and PC, laboratory team-works, personalized
feedback and coaching to improve every aspect of the student's work.

At the end of the course a successful student should have developed a
good ability to choose transformers, generators and motors for industrial
applications, should know the testing procedures of the electrical
machines in order to determine the principal characteristics

Intermediate tests just for students attending the course; Oral exam
based on theoretical questions oriented to assess:
- knowledge of the operating principles, electromagnetic and mechanical
behaviors of the main static and rotating electrical machines:
transformers, AC motors and generators, DC motors and generators.
- knowledge of the methods to test the electrical machines.
- ability to apply knowledge in order to derive the mathematical models
of the electrical machines in the different operating conditions.
- ability to apply knowledge in order to define the equivalent circuits
parameters and the operating conditions of the electrical machines.
- ability to apply knowledge in order to select the electrical machines for
different applications on the basis of the electrical requirements.

1) Preliminary part:
Electromechanical energy conversion. Analysis of two-phase and three-phase circuits. Power of two-phase and three-phase circuits. AC circuit relationships.
2) Transformer:
Two-winding transformer. Core loss current, magnetising current. Leakage reactance. Linear equivalent circuit. Phasor diagrams. Voltage drop. Three-phase transformer connections. No-load current distortion. Vector group. Determination of equivalent circuit parameters. Efficiency. Autotransformers. Instrument transformers.
3) Synchronous machine:
Cylindrical-rotor synchronous machine. Representation of airgap m.m.f. waves. Phase inductances. Mutual inductances. Vector equation of cylindrical-rotor synchronous machine. Magnetizing inductance. Synchronous inductance. Phasor equation. Steady-state equivalent circuit. Rotating magnetic fields. Vector and phasor diagram of cylindrical-rotor synchronous generator. Torque, power versus angle characteristic. Potier triangle. Saturated reactances. Salient-pole machines. Permanent magnet machines.
4) Asynchronous machine:
Wound rotors and squirrel cage rotors. Vector equations of asynchronous machine, slip frequency. Magnetizing inductance. Steady-state equivalent circuit. Slip-torque relationship. Determination of equivalent-circuit parameters. Efficiency. Starting and braking, speed control. Variable-voltage, variable-frequency control. Brief overview about single-phase induction motors.
5) Direct-current machine:
Armature windings, field excitation, armature reaction. Interpoles, compensating winding. Separately excited machine, shunt machine, series machine, compound machine. Load characteristics of generators. Speed-torque characteristics of motors. Motor starting and braking, speed control. Variable-voltage speed control.
6) Laboratory activity: transformer tests.
7) Simulated tests of the electrical machine: execution criteria of electrical-machine tests to determine machine parameters and operating characteristics. Data processing of electrical-machine tests.