Improvements in Dynamo Electric Machines.
Year: 1888

page_text: Date of Application, 6th Sept., 1888
Complete Specification Left, 6th June, 1889-Accepted, 6th July, 1889
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Electric Machines.
We, THOMAS PARKER, of Commercial Road, Wolverhampton, in the County of
Staffordshire, Engineer, and WILLIAM LOWRIE, of 117, Bishopsgate Street, in the
City of London, Engineer, do hereby declare the nature of this invention to be as
follows
==
Our invention relates to dynamo machines, and while it is especially intended for
revolving magnet multipolar alternating current generators, it may be applied, (or
parts thereof), to other types and forms of the said machines."
Hitherto, it has been the custom in the case of multipolar revolving magnet
dynamos to limit the quantity of iron in the armature or armatures (where iron was
employed), so that it was almost always much less than the amount in the revolving
field magnets.
These magnets, with their exciting coils, thus formed the heaviest
part of the machine, and for economy of driving power, as well as convenience of
construction, they have been practically displaced by the opposite type of fixed magnet
ani revolving armature machines.
Furthermore, owing to the time required to alternate the polarity of the magnetic
molecules, it was found practically impossible in either class of machines to get a
large number of current alternations without such a development of heat as greatly
reduced the efficiency of the machine, and this quickly affected the insulation of the
coils. These difficulties apparently led to the abandonment of the use of iron in the
armature, the machines being so constructed, that the field was made as complete
as possible without necessitating the alternation of magnetism in any part of the
field.
Our invention lies in a direction opposite to the general practice indicated above,
inasmuch as we still employ iron in the armature to support the magnet coils, and
use it in such quantity that the iron in the armature never approaches the condition
of saturation. For this purpose the said quantity should be at least double the
amount of iron in the magnets, but we would furlier state, that we have no objection
to the latter being at or near its point of saturation.
Our improvements further relate to the general construction of multipolar dynamo
machines and more especially to the armature conductor coils, whereby greater
simplicity and efficiency is obtained in this class of machines, and facilities are
afforded for repairs or alterations. A typical machine is as follows:
.
Upon a suitable bed plate we secure pedestals and bearings for the shaft which
carries the multipolar field magnets. The latter consist of a solid soft iron ring or
rings with a number of radially arranged pole pieces attached thereto, or forming
solid parts thereof. The magnet ring is secured to the shaft, and revolves therewith,
This hub piece may
by means of a hub or boss, having a number of radiating arms.
be made of non-magnetic material, to avoid magnetic short circuiting, but we prefer
to make it of cast iron or steel and with such a number of radiating arms that each
of them has the same relative position to a pole of the same kind. We place the
extremity of each arm either opposite a pole piece, or in a space between two con-
tiguous pole pieces, as may be most convenient; and as the hub and its arms thus
virtually form extensions in length of the magnets, magnetic short circuiting is
avoided. The magnets are conveniently attached to the ring by soft iron bolts,
Tshaped in section, passing through the ring and secured upon the inside of the
latter. The head of the bolt, being sunk into the outer extremity of each radial
magnet, forms part of the pole, and the projecting ends of the bolt heads keep the
coils in their places.
The magnets are wound in the usual manner to form alternate North and South

page_text: poles when excited, and the exciting current is conveyed thereto through the inter-
vention of insulated rings of gun metal, phosphor bronze or similar material, secured
to the shaft, and contact brushes; in the well known manner.
The standing armature consists of a magnetic ring, concentric with, and surrounding
the polar extremities of, the revolving field magnets. The armature ring is built up
of rings of sheet iron situated in parallel planes perpendicular to the axis of the ring.
If the ring is. of large size, each individual layer on element may be composed of
segments arranged so, that the segments of contiguous layers break joint with each
other and each layer of plates is carefully insulated. from adjoining layers. The
entire ring is enclosed and held in position by two cast iron cheeks or side frames,
the whole being bolted together transversely at suitable intervals. In the machine
we are now describing, the cheeks are annular rings with flanged bases, by which.
they are bolted to the base plate of the machine. The openings upon the sides
of the cheeks are likewise concentric with the field magnet ring, and are slightly
larger in diameter than the outer diameter of the field magnets.
The cylindrical inner surface of the armature ring has no recesses or projections
of any kind, but is concentric throughout its extent with the revolving field magnets.
The armature coils are thus not only in a very strong magnetic field, but there
are no sudden transitions, breaks, or changes of distance between the mass of iron
in the armature and the revolving poles; therefore there are no points in the
former to become hot. The induced magnetic poles thus flow around the armature
in a constant, uniform manner, corresponding to the travel of the magnets; and as
there are no changes of relative distance, there are no points at which the lines
of force tend to be wastefully distributed, while the large mass in the armature
allows the lines of force to pass easily around without distorting the field in which
the coils are passing.
An important feature of our invention is also that the armature conductor coils
are formed of narrow tape, each wound in a plane (or slightly curved to suit the
radius) upon a piece of insulating material of the same thickness as the width of the
tape, and rounded at the ends. The coils are thus of a flat link shape, the edges of
the tape windings being exposed upon the flat surfaces of the coils, and therefore
well able to resist deflection. These coils are placed close together upon the cylin-
drical inner surface of the armature ring, so that the axis of each coil is radial to
the ring and are secured to the same by rebated strips of wood, or other insulating
material, screwed to the cheeks, and extending over the ends of the coils, outside the
line of travel of the magnets. By this mode of construction the whole of the con-
ductor (except
a small portion at the ends of the coils, outside the line of travel of the
field, and therefore useless for inductive purposes), is placed in a strong and uniform
magnetic field of force; each turn of conductor under exactly the same inductivo
influence, and at the same distance from the moving poles, and consequently, in the
best position for efficiency.
Another great advantage is that no special means are required to keep the con-
ductors from sagging, or lifting from their normal position, as in other machines;
and as no wiring or other like means are used for the purpose named, the clearance
space between the revolving magnets and the standing conductors, is reduced to a
minimum. Furthermore, as the armature coils are simply secured to the face of the
armature, they are easily removed or replaced as required; and this remark applies.
likewise to the magnet winding. The whole of the armature ring (with its attached
coils, if necessary,) is adapted to be drawn away sideways, thus exposing the whole of
the field magnets and armatures for inspection or repair; or we may move the field
magnets along the. shaft,, or shaft and field magnets together. We sometimes, however,
cut the armature ring in two upon a horizontal line, so that the upper half is removable
for the purpose indicated, and bolt the two halves together in working position by
suitable flanges, bolts and nuts.
.
The central part of the field magnets is enclosed to avoid atmospheric resistance,
but the poles and their windings, projecting beyond the ring to which they are
attached, act somewhat as fans, and tend to keep the armature cool by the air set

page_text: in motion. The main bearings are kept cool by a chamber in which water is allowed
to circulate under a slight head of pressure; and the brasses in the said bearings are
turned and fitted into their places in such a manner, that they may be revolved in
their seats and taken out or renewed, without lifting the shaft entirely out of
its bed.
It has already been indicated that the shape or arrangement of the field magnets
may vary, and that the armature ring could be correspondingly formed without
departing from the nature of our invention. It will be apparent, also that the coils
may be likewise modified to suit these changes, and still preserve their efficiency.
Another good modification consists in forming the magnetic poles or projections on
each side face of the ring, the coils being either wound on each projection or on the
ring between the projections. The iron of the armature is still kept in the same
relation to the field, being built up of strips bent around a central former and clamped
with an outer ring one of these armatures is placed on each side of the field ring,
and the coils fixed to the vertical faces would be formed radially and clamped as
before. It is apparent, that a one-sided field could be used, and that many combi-
nations of these forms can be easily designed.
Dated this 6th day of September 1888
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Dynamo Electric Machines.
We, THOMAS PARKER, of Commercial Road, Wolverhampton, in the County of
Stafford, Engineer, and WILLIAM LOWRIE of 117, Bishopsgate Street, in the City of
London, 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 :-
Our invention relates to dynamo machines, and is especially intended for revolving
magnet multipolar alternating current generators, but the invention, or parts thereof
may be applied to other types and forms of the said machines.
Hitherto, it has been the custom, in the case of multipolar revolving magnet
dynamos, to limit the quantity of iron in the standing armature or armatures, (where
iron was employed), so that it was almost always much less than the amount in the
revolving field magnets. These magnets, with their exciting coils, thus formed the
heaviest part of the machine, and for economy of driving power, as well as convenience
of construction, they have been practically displaced by the opposite type of fixed
magnet and revolving armature machines.
Furthermore, owing to the time required to alternate the polarity of the inagnetic
molecules, it was found practically impossible in either class of machines to get a
large number of current alternations without. such a development of heat as greatly
reduced the efficiency of the machine, and this quickly affected the insulation of the
coils. These difficulties apparently led to the abandonment of the use of iron in the
armature, the machines being so constructed, that the field was made as complete as
possible without necessitating the alternation of magnetism in any part of the field.
Our invention lies in a direction opposite to the general practice indicated above,
inasmuch as we still employ iron in the armature to support the coils, and use it in
such quantity that the iron in the armature never approaches the condition of
saturation. For. this purpose, the said quantity should be at least double the amount
of iron in the magnets, but we would further state, that we have no objection to the
latter being at, or near, its point of saturation.
Our improvements further relate to the general construction of multipolar dynamo
machines and more especially to the armature conductor coils, whereby greater
simplicity and efficiency are obtained in this class of machines; and facilities are also
afforded for repairs or alterations.
A typical machine is shown by the accompanying drawings, of which Fig. 1 is a

page_text: side elevation, and Fig. 2 an end elevation; a part of the latter being in section.
Fig. 3 is a detailed section through the. standing armature, Fig. 4 is a developed view
of the face of the armature coils as presented to the field magnet poles, and Fig. 5 is
a section through the said coils on the curve occupied by them when mounted on a
standing armature. Fig. 6 is a transverse section through the magnet ring or rings,
showing an elongated pole piece and mode of attachment to the former, and Fig. 7 is
a plan of the latter. Fig. 8 is a sectional elevation, showing two of the field magnets
as mounted upon the magnet ring or rings.
Upon a bed plate A, Figs. 1 and 2, we secure pedestals a, a, and bearings a¹, for
the shaft which carries the multipolar field magnets. The latter consists of a
solid soft iron ring or rings B, with a number of radially arranged pole pieces b, b
attached thereto, or forming solid parts thereof. The magnet ring B is secured to
the shaft a, and revolves therewith, by means of a hub or boss C having a number
of radiating arms e, c, and is usually called a spider. This hub piece may be made
of non-magnetic material, to avoid magnetic short circuiting, but we prefer to make
it of cast iron or steel and with such a number of radiating arms that each of them
has the same relative position to a pole of the same kind. We place the extremity of
each arm c, either opposite a pole piece, or in a space between two contiguous pole
pieces. as may be most convenient and as the hub and its arms thus form virtual
extensions in length of the magnets, magnetic short circuiting is avoided. The
magnets b, b, (as shown by Fig. 8), are conveniently attached to the ring B by soft
iron bolts, T shaped in section, passing through the ring and secured to the inside
of the latter.. The head of the bolt b, being sunk into the outer extremity of each
radial magnet, forms part of the pole, and the projecting ends of the bolt heads keep
the coils in their places.
The magnets are wound in the usual manner to form alternate North and South
poles when excited, and the exciting current is conveyed thereto through the inter-
vention of insulated rings 6, of gun metal, phosphor bronze or similar material,
secured to the shaft a², and contact brushes, in the well known manner.
The standing armature D, consists of a magnetic ring, concentric with, and
surrounding the polar extremities of, the revolving field magnets B. The armature
ring D is built of rings of sheet iron d, d, situated in parallel planes perpendicular to the
axis of the ring. If the ring is of large size, each individual layer or element may be
composed of segments so arranged as to break joint with those of the contiguous
layers; and each layer of plates in either case, is carefully insulated from adjoining
layers. The entire ring D is enclosed and held in position by two cast iron cheeks or
side frames, d', and d², the whole being bolted together transversely at suitable
intervals. In the machine we are now describing, the cheeks are annular rings with
flanged bases, d³ and d respectively, by which, they are bolted to the base plate A of
the machine. The openings upon the sides of the cheeks are likewise concentric with
the field magnet ring. B, and are slightly larger in diameter than the outer diameter
of the field magnets.
The cylindrical inner surface or inner circumferential line of the armature ring D,
has no recesses or projections of any kind, but is concentric throughout its extent
with the revolving field magnets B. The armature coils d³, d³, are thus not only in
a very strong magnetic field, but there are no sudden transitions, breaks, or changes
of distance between the mass of iron in the armature and the revolving poles;
therefore there are no points in the former to become hot. The induced magnet poles
thus flow around the armature D in a constant, uniform manner, corresponding to
the travel of the magnets; and as there are no changes of relative distance, there are
no points at which the lines of force tend to be wastefully distributed, while the
large mass of iron in the armature allows the lines of force to pass easily around
without distorting the field in which the coils are passing.
An important feature of our invention is also that the armature conductor
coils d³, d, are formed of narrow tape, each wound in a plane (or slightly curved
to suit the radius) upon a piece of insulating material de of the same thickness as the
width of the tape, and rounded at the ends. The coils are shown in Figs. 4 and 5,

page_text: and are of a flat link shape in outline, the edges of the tape windings being exposed
upon the flat surfaces of the coils to the inductive influence of the magnets, and
therefore well able to resist deflection. These coils are placed close together upon the
cylindrical inner surface of the armature ring, (as shown in Figs. 2 and 3), so that
the plane of the axis of each coil is radial to the ring. The coils d³ are secured to the
armature ring D, by rebated strips of wood d', or other insulating material, which
are screwed to the cheeks d' and d², and extend over the ends of the coils, outside
the line of travel of the magnets. By this mode of construction the whole of the
conductor (except the ends of the coils, which are useless for inductive purposes), is
placed in a strong and uniform magnetic field of force; each turn of the conductor
is under exactly the same inductive influence, and at the same distance from the
moving poles and consequently in the best position for efficiency.
3
Another great advantage is that no special means are required to keep the
conductors d³ from sagging, or lifting from their normal position, as in other
macbines; and as no wiring or other like means are used for the purpose named, the
clearance space between the revolving magnets band, the standing armature
conductors d³, is reduced to a minimum. Furthermore, as the armature coils are
simply secured to the face of the armature D, they are easily removed or replaced as
required; and this remark applies likewise to the magnet winding. The whole of
the armature ring (with its attached coils, if necessary), may be adapted to be
drawn away sideways, thus exposing the whole of the field magnets and armatures
for inspection or repair; or we may move the field magnets along the shaft a², or
shaft and field magnets together. We sometimes, however, cut the armature rings
in two upon a horizontal line, so that the upper half is removable for the purpose
indicated, and bolt the two halves together in working position by suitable flanges,
bolts and nuts.
The central part of the field magnets B is enclosed to avoid atmospheric resistance,
but the poles and their windings b, projecting beyond the ring to which they are
attached, act somewhat as fans, and tend to keep the armature cool by the air set in
motion. The main bearings a¹, are kept cool by a chamber in which water is allowed
to circulate under a slight head of pressure; and the brasses in the said bearings.
are turned and fitted into their places in such a manner, that they may be revolved
in their seats and taken out or removed, without lifting the shaft entirely out
of its bed.
It has been already indicated that the shape or arrangement of the field magnets
may vary, and that the armature ring could be correspondingly formed without
departing from the nature of our invention. This is indicated by Figs. 9 to 14 inclusive.
It will be apparent, also, that the coils may be likewise modified to suit these changes,
and still preserve their efficiency.
Fig. 9 is a transverse section through a standing armature D, and field magnet
ring B, modified so that the poles b, b, project on each side of the magnet ring B, the
exciting coils therefor being wound on the ring between the projections. The side
cheeks and d² are arranged to hold the plates d with an uninterrupted or flat
surface close to and parallel with the plane of revolution of the pole pieces b, b; and
to this flat surface the flat armature coils d³, d³, are secured by rebated strips of
wood dwith a slight clearance space between the coils and the magnet poles.
Fig. 10 is a developed section of a small portion of the standing armature D and
the rotatable magnet ring B as shown in Fig. 9. Fig. 11 is a partial elevation or
plan of Fig. 9.
Figs. 12, 13 and 14 are corresponding views to Figs. 9, 10 and 11, of a form of
standing armature combining the features of both of our former described plans.
It will be seen that the surface of the outer set of plates d, to which the coils d³ are
secured, are turned or formed with a continuous or uninterrupted surface throughout
its interior diameter, while in those made to carry the side cheek coils, parallel to the
plane of revolution of the magnet ring, the plates d are bent around a central former
or ring which is bolted to its corresponding outer ring or side cheek as shown. In

page_text: either case, the induced magnetism in the armature flows in a continuous manner
around the latter, without a break or distortion.
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 ;-
1. A dynamo electric machine having an iron armature adapted to receive flat
armature coils upon an uninterrupted surface of the armature, the said surface being
equidistant at all points from the polar faces of the magnet or magnets employed;
substantially as described and for the purpose specified.
2. A dynamo electric machine having a standing armature composed of a mass of
iron equal to, or more than twice the amount of iron in the field magnets employed.
the said armature having one or more uninterrupted surfaces exposed towards, and
equidistant from, the polar faces of the said magnets, for the reception of armature
coils; substantially as described.
3. In a dynamo electric machine, the combination of an iron armature having an
uninterrupted surface with coils of insulated copper tape secured to the said surface,
the coils being so wound and secured to the armature as to present the copper tape
edgewise to the polar faces of the magnets employed; substantially as described and
for the purpose specified.
4. A laminated iron armature combined with flat coils of insulated copper tape
placed edgewise upon an uninterrupted surface of the said armature, and secured
thereto by rebated strips of insulating material at the ends of the said coils; sub-
stantially as described.
5. An armature coil of insulated copper tape wound in a continuous manner upon
an elongated former approximately as thick as the width of the tape, and adapted, with
its former, to be secured upon one of its faces against an uninterrupted surface of an
iron armature.; substantially as described.
6. A rotatable multipolar alternating current generating machine constructed and
operating substantially as described and illustrated by Figs. 1 to 8 inclusive of the
accompanying drawings.
Dated this 6th day of June 1980
FAIRFAX & WETTER,
433, Strand, London, Agents for the Applicants.