IMPROVEMENTS IN THE CONSTRUCTION OF DYNAMO-ELECTRIC MACHINES
Year: 1885

page_text: "
I, HENRY JONES of 48 High Street, Lambeth, London, S.E. in the County of
Surrey, Electrical Engineer, do hereby declare the nature of the said invention for
IMPROVEMENTS IN THE CONSTRUCTION OF DYNAMO-ELECTRIC MACHINES," to be
as follows:-
The improvements according to my Invention relate to that type of dynamo-
electric machine known as the Siemens H armature machine.
.
Said Invention consists in forming the armature of a series of soft iron discs,
of T form, the upper edge of the transverse member of each, forming an arc of a
circle; each disc being arranged longitudinally upon a central spindle. Said discs
are placed so that each alternate one is opposite to the one preceding it; so that
there is a space left between each individual disc of the series, equal to its
thickness. Or, I may employ discs of H form; in the latter case, washers are
interposed between each of said discs, so as to leave an intervening space, as
referred to in the first described formation of disc.
In each of the above described devices, by the adoption of the laminated
arrangement of the discs of soft iron the following amongst other advantages are
ensured. By the splitting up of the mass of metal in the armature, the so-called
Foucault currents are eliminated, and the efficiency of the machine is thereby
increased. The spaces existing between each disc in either of the arrangements
above referred to, ensure that the heat generated by the rapid reversals of
magnetization in the iron constituting the core of the armature, is dissipated, and
dispersed, by reason of the greatly increased cooling surface and the free circulation
of the currents of air produced by the rapid rotation of the spindle.
I also form the poles of the field magnets of strips of soft iron, of a suitable
shape to envelope and embrace the armature; said strips being arranged upon a
central bolt or upon central bolts, with an intervening washer or distance piece
forming a space between each strip, said bolt or bolts being secured to the cores of
the field magnets.
Under another modification of that portion of my Invention relating to the pole
pieces, I may adopt the following arrangement, that is to say, strips of soft iron are
employed, of a reduced guage or thickness to that adopted for the armature, and

page_text: formed so as to project into the air spaces between the discs of which the armature
is composed. By the aforesaid arrangements of pole pieces according to my
Invention I am enabled to ensure the perfect concentration of the magnetism of
the field magnets into the actuating magnetic field surrounding the armature, by
reason of the number of points produced and presented by such formation, and
also by the increase of effectual surface, thus giving the maximum of magnetism
with the minimum of mass. The arrangements described also present the
advantages of extreme simplicity and comparatively inexpensive construction.―
Also, by the adoption of my Invention I am enabled to allow of a dynamo machine
of the type described, whether used as a motor or generator, being driven at a high
rate of speed without the risk of impairing its efficiency and destroying its
insulation by over heating.

page_text: Improvements in the Construction of Dynamo-electric Machines.
I HENRY JONES of number 48 High Street, Lambeth, London, S.E. in the
County of Surrey, Engineer do hereby declare the nature of my invention for
IMPROVEMENTS IN THE CONSTRUCTION OF DYNAMO-ELECTRIC MACHINES and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement and accompanying sheet of
drawings:-
The improvements according to my Invention relate to that type of dynamo-
electric machine known as the Siemens H armature machine. Said Invention
consists mainly in forming the armature of a series of soft iron discs of T form, the
upper edge of the transverse member of each forming the arc of a circle, and each
disc being arranged longitudinally upon a central spindle. Said discs are placed so
that each alternate one is opposite to the one preceding it, and leaving a space
between each individual disc of the series equal to the thickness of each of such
individual discs.
Instead however of employing discs of T form as aforesaid, I may adopt an
H formation of discs. In which latter case washers are interposed between each of
said discs so as to leave an intervening space precisely as in the case of the
T formation of discs. But, in each of said arrangements or devices the laminated
disposition of the discs of soft iron presents the following amongst other
advantages; that is to say: Firstly-By the splitting up of the mass of metal
in the armature, the so called Foucault currents are eliminated and the efficiency
of the machine is thereby materially increased. Secondly:-The spaces aforesaid
presented between each disc of the series in either of the bereinbefore described
arrangements ensures that the heat generated by the rapid magnetisation and
de-magnetisation of the iron constituting the core of the armature, is dissipated or
dispersed by reason of the greatly increased cooling surface and the free circulation
of the currents of air produced by the rapid rotation of the apparatus,
I also form the poles of the field magnets of strips of soft iron of a suitable shape
to enclose the armature, said strips being arranged upon a central bolt, or bolts,
with an intervening washer or distance piece to form a space. Said bolt or bolts
being secured to the cores of the field magnets. Under another modification of,
that portion of my invention, relating to pole pieces I may adopt the following
arrangement. That is to say strips of soft iron are employed, of a reduced gauge or
thickness compared with that adopted for the armature, and so formed as to project
into the air spaces between the discs of which the armature is composed:-By
means of the aforesaid arrangements of pole pieces according to my Invention, I am
enabled to ensure the perfect consentration of the magnetism of the field magnet
into the actuating magnetic field sourrounding its armature owing to the number
of points presented under such arrangements, and also by the resultant increase of
effectual surface, thus giving a maximum of magnetism with a minimum of mass
of metal.
The several arrangements and formations herein described in accordance with
my Invention both in respect to the armature and the pole pieces present

page_text: the advantages afforded by extreme simplicity and comparatively inexpensive
construction. Also by the adoption of my Invention I am thereby enabled to
ensure that a dynamo-electric machine of the type hereinbefore referred to may be
driven at a high rate of speed without the risk of imparing its efficiency and
destroying the insulation.
Referring to the accompanying sheet of drawings illustrative of my said
Invention, Figure 1 represents an end elevational view of the laminated armaturo
aforesaid, A A, embraced by the laminated pole pieces B B with bolts C C holding
said pole pieces upon the field magnet cores which may be of cast iron of any
suitable form desired, provided with suitable lugs to hold the dovetail clips & a.-
Washers as hereinbefore mentioned are interposed between the soft iron stampings
forming the pole pieces B B said washers 66 are shewn by dotted lines in Fig. 1.
but are shewn in full, in section, in Fig. 2—which latter is a longitudinal sectional
view of a dynamo-electric machine in accordance with my said invention taken on
line A B Figure 1. Referring again to said Figures 1 and 2 the armature A A, is
here made up of alternate laminations of soft iron stampings forming an H armature
with laminated pole pieces B B with air spaces intervening. Also, in the
arrangement.here shewn, a laminated core D is employed but without intervening
spaces; the wire in this case being wound upon a solid core though such entire
core is made up of a series of strips or laminations. The whole armature is
threaded upon the shaft E. The bolts F, serve as herein before mentioned to allow
thereby of the laminated pole pieces being firmly secured upon their respective
magnetic cores and to the frame of the dynamo electric machine of which they form
a part.
As will be seen on reference to Figure 3 of the accompanying sheet of drawings
I may in accordance with my Invention construct the armature of alternate
stampings A', A³, whereby I obtain the divided poles and laminated, yet solid, core,
when threaded upon bolts passed through holes f, f. Under such disposition or
arrangement, I employ two ends of non-magnetic material for connection to the
central shaft of a dynamo-electric machine constructed in accordance with my
Invention.
I wish it also to be understood that I may use in connection with the laminated
pole pieces herein before referred to and described, alternate strips of sheet iron
which may form the field magnet cores in lieu of the cast iron cores hereinbefore
mentioned.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
I claim is
Firstly. In a dynamo-electric machine the laminated disposition or arrangement
of armature substantially as and for the purposes herein described and set forth and
as shewn in the accompanying drawing.
Secondly. In a dynamo-electric machine the disposition or arrangement
substantially as herein described and set forth and as shewn in the accompanying
drawing relating to pole pieces and their magnetic cores.