** **

** **

**Prof.
Ion Boldea May 2002**

**IEEE
Fellow**

**A
review of the book:**

** **

**“Permanent
Magnet Motor Technology-design and applications”/second edition**

**by J.F.
Gieras & M. Wing,**

**
**

published by
Marcel Dekker Inc, New York. Basel, 2002, http://www.dekker.com

Permanent Magnets, which may be considered as equivalents of
“superconductor coils at room temperature” at affordable prices, have brought
to electric motors the advantages of lower losses and higher torque densities
in the whole speed range for a myriad of applications from hard disk and DVD
drives to Electric and Hybrid vehicles. PM motors markets are already rather
mature but very dynamic though.

**This second edition**, revised and expanded, of J.F. Gieras and M.Wing’s book with
same title and publisher printed first in 1996 , structured in **12 chapters**
with **2 Appendixes**, along **583 pp.**, is dedicated to this timely
subject.

It is both an
up-to-date monograph and a textbook for senior-undergraduate or graduate
courses but it is remarkably practical and thus useful as a handbook for PM
motor design and industrial engineers.

It covers both basic principles and performance but also
advanced models and configurations with their design. The numerical examples
abound to give

a strong feeling of magnitudes.

The authors’ remarkable work and experience in the field is
reflected in the contents, but the references are fully representative and
their contribution is given notable priority.

The book starts with an Introduction where the main brush and
brushless PM motors are presented and their superior performance is explained.
Fundamentals of machine mechanics are also given.

Permanent Magnet Materials and Circuits are presented in
considerable detail in Chapter 2.

Finite Element Analysis basics and its application to
calculate the field distribution, torque and inductances of PM motors are given
in Chapter 3 in a synthetic manner.

Chapter 3 contains a thorough analytical theory of PM
Synchronous (brushless ac) Motors with frequent FEM validation examples.

The dc Commutator PM Motors are treated in chapter 4 in terms
of construction, fundamental equations, sizing procedure, speed control,
magnetic circuit and applications

Fundamental relationships, phasor diagram, reactances, rotor
configurations, dynamic model, noise and vibration and applications are the main subjects of chapter 5.

Chapter 6 deals with d.c.
Brushless(trapezoidal current) Motors from fundamental equations,
commutaion, emf and torque to rotor
position sensing,

sensorless operation, smart (integral) motors and
applications.

Axial flux (air-gap) PM Motors with their various
configurations, theory, performance and applications are presented Chapter 7

High Power Density Brushless Motors are given a rather detailed treatment in Chapter 8, stressing the
necessity of reducing the armature effect to maintain a reasonable power factor
and thus a reasonable converter cost. Though cylindrical rotor configurations
are treated, the main attention is focused on the “Transverse Flux
Machine” with a convincing design example
available. Potential applications are illustrated.

Brushless Motors of special construction-single-phase,
micro-motors and high speed PM and slotless motors- are presented in Chapter
9 while Chapter 10 pertinently treats stepping PM motors.

Design optimization is dedicated a full Chapter (Chapter 11)
where various methods are introduced and ranked and two numerical examples -
one for the dc brush and the other for the PM synchronous motor - are given.

Aspects of maintenance are treated in considerable detail in
Chapter 12.

Formulae for leakage inductances and losses of ac motors are
given in the two Appendixes.

A bibliography with 266 titles and an index close the book at
page 590.

In summary we can say that this new edition is up-to date, it covers a large spectrum of theoretical and practical issues in considerable depth, and thus it should be on the desk of all who intend to study, design, fabricate or use PM motors in practically all industries.