An Improved Dynamo Electric Machine.
Year: 1887

page_text: Date of Application, 13th Jan., 1887
Complete Left, 13th Oct., 1887
Complete Accepted, 13th Jan., 1888
An Improved Dynamo Electric Machine.
1, HENRY HARINGTON LEIGH, practising as Phillips & Leigh, at No. 22,
Southampton Buildings, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, do hereby declare the nature of my said invention as the same has been
communicated to me by Jean Louis Clerc, residing at Paris, in the French, Republic,
Engineer, to be as follows:
:-
The dynamo machine which is the subject of the present application for a Patent is
one with alternating currents which are generated by the use of coils in fixed field
magnets of a novel construction in combination with an ordinary rotating armature.
The armature consists of pairs of cylindrical coils (say 16) forming (say 8) electro
magnets. The coils are fixed radially to the axis of rotation, and in such a position
that their poles rotate past the poles of the field magnets.
The coils are wound so as to produce alternating polarities for two adjacent
magnets, and are excited by the current taken from a field magnet coil, the current
of which is maintained, by a commutator keyed upon the armature axle.
The commutator consists of three copper or brass rings embracing an insulated
sleeve and insulated from each other. None of these rings are regular, that is, their
projections are not of equal length nor of the same width throughout. The number
of projections of each ring is one half that of the number of field magnets. Two of
them have equal projections, while the projection of the third is equal to a fifth of
that of either of the others. The three rings are fixed relatively to each other in such
a way that at a given moment the current is interrupted for the purpose of avoiding
short circuiting or sparking. The rings having the major projections are connected
to the armature wires, while that one which has a projection only a fifth that of the
others is unconnected and may be if required replaced by some other insulator. The
coils of the armature are wound either singly or in series, their connection with the
exciting coil of the field magnet being effected by a pair of brushes which are
mounted in such a way that as one is leaving one projection on the commutator to
contact with the next, the other of them is upon the unconnected projection.

page_text: The coils of the field magnets are made by winding a copper wire upon a core of
iron wire which core is made by winding an insulated iron wire upon a mandrel
(suitably cut away to receive the same) of the shape in elevation of a distended U,
which is then inverted upon a suitably shaped wood sole plate by means of which the
coils are fixed to the side plates of the machine.
The ends of the U shaped mandrel constitute the pole pieces of the field magnets.
The mandrels may be of any required cross section and may be attached to the
opposite sides of a double sole which can then be separated longitudinally.
The use of soft iron in the form of an insulated wire endows the dynamo with a
capacity of very rapid magnetisation and demagnitisation.
The coils of the field magnets may be coupled either singly or in series.
Dated this 12th day of Jan1807

page_text: An Improved Dynamo Electric Machine.
1, HENRY HARINGTON LEIGH, F. Inst. P.A., practising as Phillips & Leigh, at
No. 22, Southampton Buildings, Chancery Lane, in the County of Middlesex,
Engineers and Patent Agents, do hereby declare the nature of this invention, as
the same has been communicated to me from abroad, by Jean Louis Clerc, residing at
Paris, in the French Republic, Engineer, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement
The dynamo electric machine which is the subject of this application for Letters
Patent is one working with alternating currents. These are produced by the use of
coils in fixed field magnets of a novel construction in combination with an ordinary
rotating armature.
Substantially this machine consists of a rotating armature and a fixed field magnet.
In order that the invention, and the means by which it may be carried into
practical effect, may be thoroughly understood, I will describe the same in detail,
reference being had to the accompanying drawings which are to be taken as part of
this specification.
Fig. 1 is a side elevation of the machine.
Figs. 2 and 3 are, respectively, plan and elevation of the mandrel used in the
process of winding a core of iron wire.
Fig. 4 is an illustration of one element of the rotating armature and field magnet.
Fig. 5 is a sectional elevation taken through the axis of the machine.
Fig. 6 is a side elevation, on an enlarged scale, of the commutator.
Figs. 7, 8, and 9 are part sections of the commutator, taken, respectively, on the
lines II, II-II, III-III, of Fig. 6.
The armature A is composed of pairs of say 16 cylindrical coils producing con-
sequently 8 complete electro magnets B. The coils are fixed around a rotating
shaft (, and radially to the axis of rotation, in such a way that their poles rotate past
the poles of the field magnets.
The coils are wound so as to produce alternating polarities for two adjacent magnets,
and are excited by the current taken from one of the field magnets, the current of
which is maintained by the commutator E keyed upon the shaft C.
The commutator consists of rings F, G, H, of either copper or brass, embracing an
insulating sleeve, I, and insulated from each other. None of these rings are regular,
that is, their projections are not of equal length, nor of the same width throughout.
The number of projections of each ring is one half that of the field-magnets. Two of
them have equal projections, while the projection of the third is equal to a fifth of that
of either of the others. The three rings are fixed relatively to each other in such a
way, that, at a given moment, the current shall be interrupted for the purpose of
avoiding short circuiting as well as sparking. The rings, F and G, are connected to
the respective armature wires, whilst the ring, H, is unconnected; and may even be

page_text: replaced by insulating material, if desired. The coils of the armature are wound
either singly or in series, their connection with the exciting coil of the field-magnet
being effected by a pair of brushes J, K, fixed in such relative positions that as one is
leaving one projection on the commutator E to contact with the next, the other of
them shall be upon the unconnected projection H.
The above described commutator is applicable to electric motors as well as to
generators.
The field D which forms the distinguishing feature of this invention in virtue of its
novel method of manufacture, consists of a greater or smaller number of coils; eight
in the machine described.
The several coils of the field magnet are produced by winding a copper wire of
greater or smaller gauge upon a core of iron wire L. This core is made by winding
an insulated iron wire upon a mandrel built up of four rectangular picces, M, fixed
upon a duplex wooden sole-plate, N. The squares, M, have a suitable slot cut in
their surface to receive the wire, and are cut away so that the sole-plates, N, shall
conform to the shape which it is intended that the core should possess. Figs. 2 and 3
illustrate the mandrel, in plan and elevation, respectively. When the cavities are
filled with wire, the core is separated by a saw-cut which severs the two sole-plates,
and so produces two coil-cores which then present the appearance of a distended U-
see Fig. 1. The process of winding is then completed. The pole pieces are turned
towards the centre for the purpose of being in proper relation with the armature poles.
The use of soft iron, in the form of an insulated wire, endows the dynamo with a
capacity of very rapid magnetisation, and demagnetisation. As already pointed out,
one or more of the field magnets excites the armature, the others excite the outer
circuit. They may be coupled either singly or in series.
This invention, as far as the field magnets is concerned, is not confined to making
them of any particular shape, as they may be made according to said invention of
any shape.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, as it has been commuicated
to me from abroad, I declare that what I claim is :-
1. The method of manufacturing coils by winding an iron wire upon slotted
mandrels of the desired outline, and the application of said method to dynamo-electrical
apparatus.
2. The general construction of a dynamo-electric machine, substantially as
herein before described with reference to the accompanying figures.
3. The hereinbefore described commutator adapted to cut out the coils at the
moment of reversal of current in combination either with electric generators or
electric motors.
Dotal this 12th day of Ontalier 1987