58537 - Design of electrical machines

Academic Year 2009/2010

  • Docente: Fiorenzo Filippetti
  • Credits: 3
  • SSD: ING-IND/32
  • Language: Italian
  • Teaching Mode: Traditional lectures
  • Campus: Bologna
  • Corso: First cycle degree programme (L) in Electric Engineering (cod. 0047)

Learning outcomes

The aim of the course is to give to the students a general methodology for the electrical machine design. During the course the power transformers and the induction motors will be assumed as practical cases.

Course contents

References on magnetic circuits

Magnetic circuits. Magnetic materials. Magnetic potential and reluctance. Utilization of magnetic materials, aircores. Magnetic circuit lows. Magnetization characteristic. Analysis and design of magnetic circuits.

 

Design

Design procedure of an equipment: initial machine dimensions and verification calculation; specifications, constraints and output requirements. The feasible design. The optimum design. Verification and criteria for updating the design choices.

 

General issues on the dimensioning of electrical machines

General design formulas.  Utilization coefficients.  Similar machines.  Normalization of the dimensions and the powers.  Types of cooling and types of service.  Initial transformer dimensions.  Initial induction motor dimensions. Initial dimensions of other machines (notice).

 

Transformer design

Specifications, constraints, output requirements.  Magnetic circuit and turn number calculation.  Windings calculation.  Calculation of the insulating thickness and of the axial and radial overall dimensions.  Calculations of verification for efficiency, losses ratio and voltage drop.  Calculation of the short circuit voltage and the no-load current.  Dimensioning of the container.  Thermal verification.

 

Elements of computer aided design

CAD of electrical machines.  Design formulas:  the case of the transformer, the case of the induction motor.  Mathematical algorithms for updating the design choices:  the method of the pivot function;  the method of the dispersion; other algorithms.  Logical Flow-chart of a program for automatic design.  Software environments suitable for the automatic design.

Readings/Bibliography

R. Sacchetti: Calcolo delle macchine elettriche, Pitagora Editrice, Bologna

E. Pagano, A. Perfetto: Costruzioni elettromeccaniche, Editrice Massimo, Napoli

G. Someda: Costruzione delle macchine elettriche, Editrice Patron, Bologna

Teaching methods

Lectures and computer aided design

Assessment methods

The final exam consists of a written part and an oral part

Teaching tools

Software workbenches for the machine design

Office hours

See the website of Fiorenzo Filippetti