Chapter I: Front Matter

THE THOUGHT IS IN THE QUESTION THE INFORMATION IS IN THE ANSWER

HAWKINS
ELECTRICAL GUIDE
NUMBER
TWO

QUESTIONS
ANSWERS
&
ILLUSTRATIONS

A PROGRESSIVE COURSE OF STUDY
FOR ENGINEERS, ELECTRICIANS, STUDENTS
AND THOSE DESIRING TO ACQUIRE A
WORKING KNOWLEDGE OF

ELECTRICITY AND ITS APPLICATIONS

A PRACTICAL TREATISE

by

HAWKINS AND STAFF

THEO. AUDEL & CO. 72 FIFTH AVE. NEW YORK.

COPYRIGHTED, 1914,
BY
THEO. AUDEL & CO.,
NEW YORK.

Printed in the United States.

TABLE OF CONTENTS
GUIDE NO. 2.

=THE ARMATURE= 221 to 228

Definition--=how continuous current is obtained=--type
of armature--comparison ring and drum armatures--=why drum
armature is the prevailing type=--disc armatures--why disc
armatures were abandoned.

=ARMATURE WINDINGS= 229 to 256
Preliminary considerations--=winding diagrams and winding
tables=--lap and wave winding--angular pitch or spread of
drum coils--parallel or =lap winding=--series or =wave
winding=--double-windings--Siemens winding--objection
to Siemens winding--=chord winding=--multiplex
windings--number of brushes required--number of armature
circuits--=equalizer rings=--=drum winding
requirements=.

=THEORY OF THE ARMATURE= 257 to 282
Current distribution in ring and drum armatures--=connection
of brushes=--variation of voltage around the
commutator--=cross magnetization=; field
distortion--remedies for field distortion--angle of
lead--demagnetizing effect of armature reaction--=effect of
lead=--=eddy currents=; lamination--remedy for eddy
currents--magnetic drag on the armature--smooth and slotted
armatures--comparison of smooth and slotted armatures--magnetic
=hysteresis= in armature cores--=core loss= or iron
loss--dead turns--friction.

=COMMUTATION AND THE COMMUTATOR= 283 to 302
=Period of commutation=--commutating
plane--normal neutral plane--neutral plane--plane
of maximum induction--commutation--position
of the brushes--=sparking=--effect of
self-induction--construction of commutators--=points
relating= to commutators--types of commutator.

=BRUSHES AND THE BRUSH GEAR= 303 to 320
Classification--gauze brushes--wire brushes--strip
brushes--=carbon brushes=--adjustment--comparison of
copper and carbon brushes--size of brushes--number--=contact
angle of brush=---brush contact--drop in voltage at
brushes--=brush holders=--brush rigging--multipolar brush
gear.

=ARMATURE CONSTRUCTION= 321 to to 348
Parts--shaft--core--slotted core--=core
laminations=--core bolts--attachment to
shaft--insulation of core discs--teeth--advantages and
defects of slotted armatures--slotted cores; built
up construction--=ventilation=--=insulation
of core=--armature windings--construction of
inductors--objection to copper bars--=various windings=:
hand winding--evolute or butterfly winding--connectors--barrel
winding--bastard winding--former winding--former
coils--peculiarity of evolute coil--"straight out"
coil--=coil retaining devices=--driving horns.

=MOTORS= 349 to 388
Definition--=principles=--propelling drag--essential
requirements of construction--=the reverse electromotive
force=--hydraulic analogy--action of current supplied
to motor--=armature reaction= in motors--method
of starting a motor---classes of motor; =series,
shunt, and compound=--power of a motor--brake horse
power--mutual relations of motor torque and speed--=speed
regulation=--series parallel controller--=interpole
motors=.

=SELECTION AND INSTALLATION= 389 to 406
=General conditions governing
selection=--=construction=--efficiency--adaptation of
series and shunt motors--location--foundations--=erection
of dynamos and motors=--connecting up dynamos--marine
generating set--belt clamp--belt lacing--belt
speed--=points relating to belts=--gear drive--friction
drive--=electrical connections=.

=AUXILIARY APPARATUS= 407 to 430
=Switches=--switch classification and
construction--difficulty encountered in opening the
circuit--=various switches=: knife, snap, and
quick break types--=fuses=--circuit breakers:
maximum, minimum, reverse current, maximum and reverse
current, no voltage breaker--=discriminating cut
out=--time limit attachments--=rheostats=--starting
boxes--=switchboards=.