Improvements in Armatures of Dynamo Electric Machines.
Year: 1895

page_text: Date of Application, 13th Mar., 1895
Complete Specification Left, 13th Dec., 1895-Accepted, 18th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements in Armatures of Dynamo Electric Machines.
We, ALEXANDER BEWICKE BLACKBURN Chief Engineer of The Electric
Construction Company Limited of Wolverhampton in the County of Stafford and
THOMAS LARGE BOYDEN Engineer of The Electric Construction Company
Limited of Wolverhampton aforesaid do hereby declare the nature of this invention
to be as follows:-
The invention consists of improvements in wire wound drum armatures of
dynamo electric machines and relates to those armatures in constructing which
the winding is first wound on shapes or formers in separate coils or groups of coils
and afterwards placed in position on the drum or core and it has especial reference
to high voltage machines and that class of machines in which a number of wires
(either connected to each other in series or parallel) go to form one coil when
placed on the armature core, the object of the invention being to obtain increased
efficiency by shortening the mean path of the coil at the same time simplifying the
hitherto known methods of winding the coils.
In carrying out the invention we make the armature coils of approximately
trapezoidal shape the longer and the shorter sides of which are parallel to the
axis of the armature and form the conductors proper these sides we term the limbs
of the coil and the sides of the trapezoid which are equal in length we call the
ends of the coil, the junctions of the limbs with the end of the coil we call the
tags, these latter portions of the coil are particularly necessary to enable the said
coil to fit together in the proper manner and constitute an important feature of the
invention.
In winding the coils a shape or former of the proper contour is used and the
wire is continuously wound thereon each complete convolution forming two
conductors and two end connections, each wire may be separately brought out to
the commutator or continued to form a number of convolutions in series with each
other.
The wires forming the limb of the said coil are arranged preferably in a
rectangular form but the whole of these are formed at the ends into a single flat
web of preferably only one wire in thickness and laid in a plane approximately at
right angles to the axis of drum or core but shaped to form portions of helices, the
shape of the ends when viewed normal to the end of the armature is approximate y
a segment of a circle one half of a circle (approximately) being used for a two
pole machine and one sixth of a circle (approximately) being used for a six pole
dynamo and so on. The convolutions of wire forming the coils are so wound that
the tags (before named) at the ends of the segments formed by the wires are in
opposite directions so that their surfaces are at right angles or nearly at right
angles to the surfaces of the ends and preferably immediately under the limbs of
the coil, this arrangement permits the limb of each coil to pass over the ends of
the neighbouring coil when placed in position on the armature and is necessary in
order to avoid dangerous contact of the coils at the corners where the greatest
danger to the insulation exists and in order to obtain a symmetrical and neat
arrangement of winding.
The coils are slipped one through the other next to it, the ends being side by
side but one slightly in advance of the other, the amount of advance being
determined by the condition that two contiguous tags on one side should include an.

page_text: angle having its apex at the axis of the armature twice as great as that between:
two contiguous limbs on the armature.
Dated this 13th day of March 1895.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Armatures of Dynamo Electric Machines.
We, ALEXANDER BEWICKE BLACKBURN Chief Engineer of The Electric
Construction Company Limited of Wolverhampton in the County of Stafford and
THOMAS LARGE BOYDEN Engineer of The Electric Construction Company
Limited of Wolverhampton aforesaid do hereby declare the nature of this
invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
The invention consists of improvements in wire wound drum armatures of
dynamo electric machines and relates to those armatures in constructing which the
winding is first wound on shapes or formers in separate coils or groups of coils
and afterwards placed in position on the drum or core, and it has especial reference
to high voltage machines and that class of machines in which a number of wires
(either connected to each other in series or parallel) go to form one coil when
placed on the armature core, the object of the invention being to obtain increased
efficiency by shortening the mean path of the coil at the same time simplifying the
hitherto known methods of winding the coils.
The accompanying drawing will assist the description of this invention.
Figures 1 and 2 are views of a coil at right angles to each other
Figure 3 is a section on the line A. B. Figure 1, and
Figure 4 is an enlarged view of one of the tags hereinafter described.
In carrying out the invention we make the armature coils of approximately
trapezoidal shape the longer and the shorter sides (a and b) of which are parallel
to the axis of the armature and form the conductors proper these sides we term
the limbs of the coil and the sides (c and d) of the trapezoid which are equal in
length we call the ends of the coil, the junctions of the limbs with the ends of the
coil, we call the tags, these latter portions of the coil are particularly necessary to
enable the said coil to fit together in the proper manner, and constitute an inportant
feature of the invention.
In winding the coils a shape or former of the proper contour is used and the wire
is continuously wound thereon each complete convolution forming two conductors
and two end connections each convolution may be separately brought out to the
commutator or continued to form a number of convolutions in series with each
other.
The wires forming the limbs of the said coil are arranged preferably in a
rectangular form but the whole of these are formed at the ends into a single flat
web of preferably only one wire in thickness and laid in a plane approximately at
right angles to the axis of drum or core but shaped to form portions of helices
as seen also in Figure 2 the shape of the ends when viewed normal to the end of
the armature is approximately a segment of a circle one half of a circle
(approximately) being used for a two pole machine and one sixth of a circle
(approximately) being used for a six pole dynamo and so ou. The convolutions of
wire forming the coils are so wound that the tags (before named) at the ends of
the segments formed by the wires are in opposite directions and so that their
surfaces are at right angles, or nearly at right angles to the surfaces of the ends
and preferably immediately under the limbs of the coil, this arrangement permits
the limb of cach coil to pass over the ends of the neighbouring coil when placed in

page_text: position on the armature and is necessary in order to avoid dangerous contact of
the coils at the corners where the greatest danger to the insulation exists and in.
order to obtain a symmetrical and neat arrangement of winding.
The coils are slipped one through the other next to it, the ends being side by
side but one slightly in advance of the other, the amount of advance being
determined by the condition that two contiguous tags on one side should include an
angle having its apex at the axis of the armature twice as great as that between
two contiguous limbs on the armature.
The coil winding as described readily permits if desired of half the coils being
first placed on the armature core and covered with insulating material and then of
the second portion of the coils being placed in position over them their end
connections being placed beyond but alongside those of the first half.
Having now particularly described and ascertained the nature of our said inven-.
tion and in what manner the same is to be performed, we declare that what we
claim is :-
In, or for, dynamo electrical machines a detachable wire-wound armature coil of
trapezoidal form and having conductors and helical end connections united by tags,
or junctions, formed by the wire in a plane approximately at right angles, to the
plane of the helix at either side thereof substantially as hereinbefore described and.
illustrated by the accompanying drawings.
Th
10 L
Dmban 1COS
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents for the Applicants.