Improvements in Dynamo-electric Generators and Motors.
Year: 1889

page_text: Date of Application, 17th Apr., 1889
Complete Specification Left, 9th Jan., 1890-Accepted, 15th Feb., 1890
PROVISIONAL SPECIFICATION.
Improvements in Dynamo-electric Generators and Motors.
I, GEORGE EDENSOR DORMAN of The Hawthorns, Stafford, in the county of
Stafford, Engineer do hereby declare the nature of this invention to be as
follows;-
The object of my invention is by a more suitable disposition of materials than
héretofor employed to considerably reduce the weight of iron and copper entering
into the construction of dynamo electric generators, and motors to reduce the space
occupied by said machines, employing a simple construction, in which the main
structure of the machine may be made in wrought or cast iron. A dynamo-electric
generator or motor constructed according to my invention, consists of a wrought or
cast iron tube, in or against or attached to the interior of said tube, and diametrically
opposite one another, being two pole pieces, between the said pole pieces and
centrally within the tube, an armature being situated, the centre line of its shaft
coinciding with the axis of the tube, the armature being supported by brackets
carried up from a bed plate, and to which the wrought or cast iron tube may be
attached, or being supported preferably by means of wrought or cast iron brackets
or end plates, secured to the ends of the wrought or cast iron tube, and which may
partially or completely enclose the ends of said tube. On the exterior of the tube,
brackets or lugs or flanges being attached or integral with said tube to fix the
generator or motor to a base or foundation rails.
Around the pole pieces within the wrought or cast iron tube, exciting coils being
located, the coils being thin and flat and being first wound and taped and then bent
or compressed in a mould or otherwise, to the exact curvature of the interior of the
wrought or cast iron tube, the coils may be made in one or for convenience in bending
or compressing in two or more sections, and one or more of the sections may be
slightly larger than the other section or sections in the same coil. The coils thus
made as nearly as possible filling the annular space, except where the pole pieces are
situate, formed between the armature and the cast or wrought iron tube. To prevent
the coils approaching too closely to the armature I interpose between the coils and
armature, curved plates of brass or other suitable material connected by or retained
in place by end cylinders.
In manufacturing I truly bore out the interior of the wrought or cast iron tube,
and fit and bolt thereto the pole pieces made in wrought or cast iron, and I fit on to
the tube; the end brackets, and I bore out the pole pieces and holes to receive
journals in the end brackets, at the same time or at the same setting at which the
pole pieces are bored, the advantage of such method in securing centrality being well
understood, and I withdraw the pole pieces after having been bored, and fit around
them the afore mentioned exciting coils, and then bolt said pole pieces permanently
in place.
COMPLETE SPECIFICATION.
Improvements in Dynamo-electric Generators and Motors.
I, GEORGE EDENSOR DORMAN, of The Hawthorns, Stafford in the County of Stafford,
Engineer, 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 object of my invention is by a more suitable disposition of materials than

page_text: heretofor employed, to considerably reduce the weight of iron and copper entering
into the construction of dynamo electric generators and motors, and to reduce the
space occupied by the said machines, employing a simple construction in which the
main structure of the machine may be made in wrought or cast iron.
A dynamo-electric generator or motor constructed according to my invention
consists of a wrought or cast iron tube, in or against or attached to the interior of
the said tube, and diametrically opposite one another being two pole pieces, between
the said pole pieces and centrally within the tube an armature being situated, the
centre line of its shaft coinciding with the axis of the tube, the armature being
supported by brackets carried up from a bed plate to which the said tube may be
attached or being supported preferably by means of wrought or cast iron brackets or
end plates secured to the ends of the wrought or cast iron tube, and which may
partially or completely enclose the ends of the said tube. On the exterior of the
tube brackets or lugs or flanges being attached or integral with the tube to fix the
generator or motor to a base or bed plate or to foundation rails.
Around the pole pieces within the wrought or cast iron tube exciting or field coils
being located, the coils being thin and flat and being first wound and taped and then
bent or compressed in a mould or otherwise to the exact curvature of the interior of
the wrought or cast iron tube, the coils being made for convenience in bending or
compressing in two or more sections, the sections being of the same size throughout,
or one or more of the sections being larger than the other section or sections in the
same coil, the coils thus made as nearly as possible filling the annular space
.except when the pole pieces are situate formed between the armature and the cast or
wrought iron tube.
By thus bending the exciting or field coils, the said coils are brought into closer
proximity to, and higher inducing action on the armature than is usual, and may
therefor be made of less weight, they further take up less space allowing the cast or
wrought iron tube or field magnet to be made correspondingly smaller. To prevent
the coils from approaching too closely to the armature, I situate on either side of the
pole pieces, retaining rings of brass or other suitable material, and the coils when
wound may be saturated with shellac varnish so as to be nearly sufficiently rigid, as
not to require additional support.
In manufacturing I bore out the interior of the wrought or cast iron tube and fit
and bolt thereto pole pieces made in wrought or cast iron, and I fit on to the tube the
end brackets, and bore out the pole pieces and holes to receive journals or bushes in
the said brackets at the same time with the same cutter or at the same setting but with
a smaller cutter, the advantage of such method in securing centrality being well under-
stood, the end brackets and pole pieces being afterwards temporarily withdrawn
or removed for the fitting of the field coils around the pole pieces or in place.
In the accompanying drawings
Figure 1 is a sectional view through the pole pieces of a dynamo electric generator
or motor made according to this invention.
Figure 2 is an exterior view.
Figure 3 is a longitudinal section.
Figure 4 is an end view of the interior of the machine the commutator end bracket
having been removed.
Figure 5 is an end view and plan of a coil forming one of the sectional coils of the
field coils.
In the figures a indicates the field coils, when the said coils are placed in position,
in addition to retaining rings b any necessary packing of wood or fibre may be placed
between them as indicated at c.
As shewn in the figures the sections of the coils a, near the armature are of less
diameter than those more distant, when all the sections in a field coil are of the same
size, they may be of the same diameter as the coil or section nearest the armature,
this coil as shewn in the figures preferably embracing as completely as possible half
of the armature surface. When the sections are of such same size or diameter or a
smaller diameter than afore mentioned the tube f may be made much shorter, but of

page_text: larger diameter and with deeper pole pieces to accomodate the same amount of wire,
as compared with the construction in which sections varying in diameter or size are
employed.
A commutator is shewn at d. When both the end brackets K and M entirely enclose
the ends of the tube f, so that brushes of normal type could not be approached,
brushes G may be fed radially to the commutator through rectangular tubes as shewn
at H, the brushes being insulated therefrom by a fibre sheath, and being pressed
forward by springs I, the current being taken to or from the brushes by a flexible J
attached to the end of the brush. If the commutator end bracket consists of two
arms supporting a central boss, or if it is otherwise made sufficiently open, rocking
yoke and brushes of ordinary type may be employed.
The pole pieces P may be made rectangular but I prefer an elliptical or oval form,
this being the shape of the central opening L in the coils a, when such have been
bent, the coils being for ease in winding preferably originally coiled on a circular
bobbin or former.
As the end brackets K and M form part of the magnetic circuit of the machine,
in order to give the least resistance to the lines of force, they are preferably made in
wrought iron and one or both should completely enclose the ends of the tube,
besides giving magnetic conductivity being additionally advantageous in excluding
dust or damp from the armature or field coils.
Bushes N which may be of the same or a smaller diameter than the bore of the
pole pieces, may be made in wrought or cast iron, and smaller bushes O of suitable
bearing metal may be fitted therein. As shewn in Figure 3 flanges t are formed on the
brackets K and M, fitting the bore of the tube F. which may serve to centralise
the bracket, when such are used the bushes N may be made integral with the bracket,
the bracket being then bored and turned in the lathe in the usual manner.
When the machine is required to carry heavy currents an air propeller may be
arranged within the machine at the pulley end of the shaft at r and may serve to
draw in air through perforations in the pulley end bracket and deliver same through
similar perforations at the commutator end bracket, thus cooling the interior of the
machine.
The different sections of the field or exciting coils a, one of which is shewn in
Figure 5 are preferably as aforementioned wound on a circular bobbin or former, the
coil being made for ease in winding about one half an inch or less in thickness, the
coils wound being then varnished taped or sheathed in suitable insulating material
and pressed in wooden dies or otherwise to the necessary curvature, or the different
sections may be wound varnished bent and placed together and then taped or
insulated over the whole set of coils, the space otherwise taken up by insulating
matter between each section coil in the field coils being thus saved.
Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1st. In a dynamo electric generator or motor an iron tube, or equivalent structure,
containing two interior pole pieces with field, or exciting coils arranged around the
said pole pieces, the coils being bent, or shaped to conform with, or fit the interior
curvature of the said tube, or equivalent structure, substantially as herein described
and shewn.
2nd. In a dynamo electric generator or motor an iron tube, or equivalent structure,
containing two interior pole pieces, with sectional field, or exciting coils arranged
around the said pole pieces, the said coils being bent, into proximity to or to embrace
the armature, substantially as herein described and shewn.
3rd. In a dynamo electric generator or motor an iron tube, or equivalent structure
containing two interior pole pieces, with field or exciting coils, arranged around the
said pole pieces, the coils being bent, substantially as herein described and shewn.

page_text: 4th. In a dynamoelectric generator or motor an iron tube or equivalent structure,
containing two interior pole pieces, and bent exciting or field coils, with end plates
or brackets, completely enclosing one or both ends of the said tube, substantially as
herein described and shewn.
Dated thin 7th day of January
1800