Year: 1887

page_text: Date of Application, 19th Apr., 1887
Complete Left, 17th Jan., 1888
Complete Accepted, 2nd Mar., 1888
I, ALPHONSE ISIDORE GRAVIER of Paris in the Republic of France, Engineer, do
hereby declare the nature of this invention to be as follows:-
The object of the present invention is to utilize, to the greatest extent, the materials
employed in the construction of Dynamo electric machines, whether designed for
generators or motors.
To this end it is proposed to place the armature within a field, the magnets of which
are either not opposed to each other, as in the ordinary fields, or, if opposed in respect
of position, are, by reason of their unsymmetrical form, caused to act and re-act in a
new manner.
The invention is applicable to various constructions of Dynamo machines, as, for
example, the Gramme, the Siemens, and the Schukert machines.
In applying the invention to the Gramme machine, instead of making the polar
extensions of the two field magnets balance each other on opposite sides of a line
drawn through the two poles and cutting the axis of the machine, the extensior of
the one pole is made to the right, reaching round 'to near the opposite pole, and 'he
extension of that pole is made to the left, reaching round to near its opposite pole
In addition to this, the armature is made to carry a quantity of wire equal to chat
of the field magnets.
The result of this modification of the machine is greatly to augment its electro-
motive force.
Nearly the whole of the armature wire is utilized to the profit of the induction,
whence it follows that the neutral field is reduced nearly to a point. Also, the magnetic
created by the circulation of the induced currents around the armature, of which the
re-action upon the field is prejudicial in all known machines, becomes beneficial, by
adding its action to that of the field magnets.
the
The like results are attained in machines of the Siemens type, by coiling only, say,
upper right hand bar of the field and the lower left hand bar of the field, or the
field magnets may be situate in different horizontal or vertical planes, their polar

page_text: extensions embracing the armature, as in the above described modification of the
Gramme type.
In the case of a magnetic arrangement of the field, symmetrical in form, but
magnetically unsymmetrical, will be found the same remarkable peculiarity; viz.,
strongly magnetized poles, and feebly magnetized or neutral poles, the first magnetizing
the ring by magnetic induction, and the second being magnetized by the influence of
the strong polarities of the ring, due to the circulation of induced electrical currents.
In order still further to augment the magnetic effect due to the unsymmetrical
arrangement of the machine, a plate of wrought iron is attached to the cast iron core
of the field magnets at a part farthest from the polar extension, before the coils are
laid thereon.
D
1

page_text: Improvements in Dynamo-electric Machines.
I, ALPHONSE ISIDORE GRAVIER, of Paris in the Republic of France, 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 this invention is to utilise, to the greatest extent, the materials
employed in the construction of dynamo electric machines, whether for the generation,
or for the utilisation, of electro-motive force. The following is a description of the
manner in which this object is effected, reference being had to the accompanying
drawings.
Taking, for example, the Gramme ring armature, the Siemen's drum, or the disc
ring of Schukert (Figs. 1, 2, 3 and 4); these armatures, instead of being placed in a
symmetrical magnetic field, in the usual way, as indicated in the figures, are placed in
a magnetic field which is unsymmetrical, such as one of those shewn in Figs. 5, 6, 7,
and 8, it being understood that an unsymmetrical magnetic field" does not mean,
necessarily, unsymmetrical in form, but magnetically unsymmetrical.
«
Figs. 5, 6, and 7 are not only unsymmetrical in form, but are also magnetically
unsymmetrical. In all these examples, the points, A and B, of the field magnets,
strongly magnetised, influence the corresponding points, b and a, of the armature, and
the points, a and b, although feebly magnetised, influence the strong polarities, A¹
and B1, of the armature favourably.
In order to augment the magnetic power of the points, A and B, they are not
rounded off, but are left sharp, as may be seen more particularly in Figs. 5, 6, 9,
and 10.
Fig. 9 shows an instance of a magnetic arrangement of the field, symmetrical in
form, but magnetically unsymmetrical, for there will be found, as in the first arrange-
ments, the same remarkable peculiarities, viz., the points A and B, strongly magnetised,
and the points a¹ and b¹ feebly magnetised, or neutral. The first magnetise the ring
by magnetic induction, and the second are magnetised by the influence of the strong
polarities, A', B', of the ring, due to the circulation of induced electrical currents.
Many other arrangements, on the same principle, may be indicated; for example,
two branches of one electro magnet, magnetised unequally, constitute an electro-
magnet, symmetrical in form, but unsymmetrical magnetically.
This principle of unsymmetrical magnetism, when employed in the construction of
dynamo machines, gives them a character altogether new, and possessing the following
advantages:
1st. The electro-motive force is considerably augmented.
2nd. The loss of tension due to the reaction of the armature upon the field magnet,
is absolutely avoided, and amounts to no more than that due to the circulation of the
induced current in the armature wire, and depends only on the electric resistance of
the armature.

page_text: 3rd. Nearly the whole of the armature wire is utilised to the profit of the induction,
from which it follows that the neutral field is reduced nearly to a point.
4th. The magnetic field created by the circulation of the induced currents around
the armature, of which the reaction upon the field is prejudicial in all known machines,
becomes beneficial by being added to that of the field magnets.
5th. These results, due to the particular magnetic form of the field magnets, permit
of a distribution of the copper wire upon the armature and field magnets differing
from that indicated by the usual construction. The constructors usually put the least
possible wire upon the armature, in order to diminish the prejudicial effect of the
reaction of the armature, and for the same end, put as much wire as possible upon the
field magnets.
In a machine constructed according to the present invention, the armature wire is,
on the contrary, augmented up to the limit when its mass becomes equal to that of the
field magnet wire, so that a machine is obtained in which the specific utilisation of
the materials is carried to its maximum.
In order, still further to augment the magnetic effect due to the unsymmetrical
arrangement of the machine, a plate of wrought iron is attached to the cast iron core
of the field magnets (see Fig. 10) by screws, or in any other convenient manner.
This Fig. 10 shows, by way of example, a form of unsymmetrical machine, which it is
proposed to employ. It is excited in derivation, and may be regarded as practically
compound; that is to say, of constant electro-motive force.
The compounding is easily effected by the addition, to the exciting wire, of a stout
wire, some yards in length, mounted in circuit with the ring.
This facility of compounding, which is due to the unsymmetrical arrangement of
the machine, permits of the construction of a machine, which will have a constant
electro-motive force, either at the terminals, or at any determinate point in the exterior
circuit.
I would here remark that my invention may be applied to all known forms of
armature.
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 dynamo-electric machines, or electro-motors, the use of field magnets,
symmetrical or unsymmetrical as to their form, but magnetically unsymmetrical, sub-
stantially as and for the purposes above set forth.
2nd. Constructing field magnets with a plate of wrought iron attached to the cast
iron cores, before the coils are laid thereon, as and for the purpose described.
3rd. Forming the armature at those parts which should be the most magnetised,
with sharp angles or corners, as above described.
Dated this 17th day of January 1888. .
NEWTON & SON,
Agents for the Applicant.