AN IMPROVEMENT IN DYNAMO ELECTRIC OR ELECTRO DYNAMIC MACHINES
Year: 1883

page_text: :
LETTERS PATENT to Robert Edward Dunston, Alfred Pfannkuche, and John
Fairlie, all of the Malden Factories Kentish Town in the county of Middlesex
for an Invention of "AN IMPROVEMENT IN DYNAMO ELECTRIC OR ELECTRO
DYNAMIC MACHINES"
PROVISIONAL SPECIFICATION left by the said Robert Edward Dunston,
Alfred Pfannkuche, and John Fairlie at the Office of the Commissioners of
Patents on the 25th October 1883.
ROBERT EDWARD DUNSTON, ALFRED PFANNKUCHE and JOHN FAIRLIE all of the
Malden Factories, Kentish Town in the County of Middlesex "AN IMPROVEMENT
IN DYNAMO-ELECTRIC OR ELECTRO-DYNAMIC MACHINES
"
Our invention relates to a cheap and simple construction of the iron coro of the
annular revolving armature employed in many dynamo-electric or electro-dynamic
machines, in such a manner as to render it more effective than these cores as they
are usually constructed, and to avoid the overheating of the armature and machine
when in work. For this purpose, we wind on a cylindrical mould a number of
convolutions of a soft iron hoop along with a tape or strip of insulating material
such as textile fabric, caoutchouc, gutta percha or the like, so as to separate each
convolution of the hoop from the next. When sufficient length of hoop and tape
has been wound on to make up the annulus to the required thickness, we secure
the ends and remove the annulus from the mould, to be wound round with
insulated wire and mounted in the machine in the usual way. The tape or strip
of insulating material should be a little broader than the hoop, so as to present an
edge beyond each side of the hoop for more effectually separating each convolution
from the next.
In winding the insulated wire on an annular armature of the kind described in
a number of separate coils, we prefer to reduce the resistance of the machine by
connecting these coils to each other and to the commutator plates in the following
manner. We join the end of the wire of one coil, not to the beginning of the wire
of the next coil in order, but to that of the second in order, and we connect each
of those junctions to a separate plato of the commutator. We make those plates
of helical form, that is to say, inclined to the axis of the commutator, so that the
brush or rubber lies over parts of several successive plates at one time.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Robert Edward Dunston, Alfred Pfannkucho, and John Fairlie in
the Patent Office on the 24th April 1884.
ROBERT EDWARD DUNSTON, ALFRED PFANNKUCHE and JOHN FAIRLIE, all of
the Malden 'Factories Kentish Town in the county of Middlesex "AN IMPROVE-
MENT IN. DYNAMO-ELECTRIC OR ELECTRO-DYNAMIC MACHINES'
"
Our invention relates to a cheap and simple construction of the iron core of the
annular revolving armature employed in many dynamo-electric or electro-dynamic
machines, in such a manner as to render it more effective than those cores as they
are usually constructed, and to avoid the overheating of the armature and machine
when in work. For this purpose, we wind on a cylindrical mould, which may be
the armature boss, a number of convolutions of a soft iron hoop, along with a tape
or strip of insulating material, such as textile fibre, caoutchouc, gutta-percha, or
the like, so as to soparate each convolution of the hoop from the next. When
sufficient length of hoop and tape has been wound on to make up the annulus to
the required thickness, we secure the ends and remove the annulus from the mould
or boss to be wound round with insulated wire and mounted in the machine in the
usual way. The tape or strip of insulating material should be a little broader than
the hoop, so as to present an edge beyond each side of the hoop for more effectually
separating each convolution from the next.
!
Figs. 1 and 2 are sections shewing a number of convolutions of iron hoop A with
interposed layers B of insulating material wound with the hoop. These layers B
are made a little wider than the hoop A, so that they project at each side, and the
projecting edges are folded over the hoop as shown in fig. 3, under the insulated
wire C, which is coiled on the hoop ring. Fig. 4 shews the hoop ring coiled over
half its extent and mounted between arms D projecting from a boss fixed on
shaft E, as shewn in the section fig. 5. The hoop A may, before it is wound, bo
coated with insulating material, and in that case the interposition of the strip B is
unnecessary.
Having thus described the nature of our invention and in what manner the same
is to be performed, we claim :—
Constructing the core of an annular armature by winding iron hoop in
convolutions along with the interposed insulating material, substantially as berein
described.
In Witness whereof I tho said Alfred Pfannkuche have hereunto set my hand
and seal this twenty fourth day of April in the year of our Lord one thousand,
eight hundred and eighty four.
ALFR
PRANNKUCHE
(L.S.)