Improvements in and relating to Apparatus for Regulating the Difference of Potential at the Terminals of Dynamo-electric and like Machines.
Year: 1898

page_text: Date of Application (in United Kingdom), 13th Dec., 1898
Complete Specification Left, 8th Sept., 1899-Accepted, 21st Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in and relating to Apparatus for Regulating the
Difference of Potential at the Terminals of Dynamo-electric
and like Machines.
I, LÉON DE COINCY, of 9, Avenue de l'Opéra, Paris, in the Republic of France,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
In the Specification accompanying my Application for Letters Patent, filed
on the 12th December 1898, No. 26,257, I have described an improved method
of and apparatus for regulating the difference of potential at the armature-
terminals of dynamo-electric and like machines, this being effected by the longi-
tudinal displacement of the armature on its shaft, in such a manner that, this
armature issuing from between the pole-pieces, the difference of potential and
the intensity of the current will diminish and will become practically zero when
the armature is completely outside the pole-pieces.
When the armature turns between the pole-pieces, the magnetic field holds it
there strongly. In order nevertheless to permit of this armature passing out of
the pole-pieces by the action of a small force, I have made an improvement in
the subject of my said former application.
This improvement consists in modifying the arrangement of the magnetic
field in such a manner that it only experiences the minimum of variation in its
distribution during the motion of the armature.
In order that I may be readily understood, I have shown, in the accompanying
drawing, by way of example only, a method of carrying my improved arrange-
ment into practice.
Let us suppose that a ring armature c, for example, is being dealt with, and
that the direction of movement of the armature, in order to issue from between
the pole-pieces, is towards the commutator brushes.
The parts must evidently be so arranged that the magnetic field is modified as
little as practicable by the motion of translation of the core of the armature.
For this purpose, it is only necessary to so to speak prolong this core, that is to
say, to mount on the shaft, as near as practicable to the armature and on the
opposite side to the commutator, a pulley or bobbin, m, called a compensator, of
soft iron, of the same diameter and of the same thickness as the core and of a
length equal to the travel of the armature.

page_text: By reason of the thickness of the wires of the armature which surround the
core, the bobbin is not the immediate prolongation of the core; there results
therefrom, during the motion of the armature, a slight discontinuity in the
distribution of the magnetic field. This discontinuity however does not present
any serious inconvenience. Nevertheless, to obviate it completely, it is only
necessary to provide the pole-pieces at this side with slight extensions 1, in such a
manner as to cover the space left free between the core and the compensating
bobbin m.
Under these conditions, a very small force is sufficient to move the armature.
Dated this 13th day of December 1898
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.
Improvements in and relating to Apparatus for Regulating the
Difference of Potential at the Terminals of Dynamo-electric
and like Machines.
I, LÉON DE COINCY, of 9, Avenue de l'Opéra, Paris, in the Republic of France,
Electrical 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:
1
In the Specification accompanying my Application for Letters Patent, filed
on the 12th December 1898, No. 26,257, I have described an improved method
of, and apparatus for regulating the difference of potential at the armature-
terminals of dynamo-electric and like machines, this being effected by the longi-
tudinal displacement of the armature on its shaft, in such a manner that, this
armature issuing from between the pole-pieces, the difference of potential and
the intensity of the current will diminish and will become practically zero, when
the armature is completely outside the pole-pieces.
When the armature turns between the pole-pieces, the magnetic field holds it
there strongly. In order nevertheless to permit of this armature passing out of
the pole-pieces by the action of a small force, I have made an improvement in
the subject of my said former application.
This improvement consists in modifying the arrangement of the magnetic
field in such a manner that it only experiences the minimum of variation in its
distribution during the motion of the armature.
In order that I may be readily understood, I have shown, in the drawing accom-
panying my Provisional Specification by way of example only, a method of
carrying my improved arrangement into practice.
Let us suppose that a ring armature c, for example, is being dealt with, and
that the direction of movement of the armature, in order to issue from between
the pole-pieces, is towards the commutator brushes.
The parts must evidently be so arranged that the magnetic field is modified as
little as practicable by the motion of translation of the core of the armature.
For this purpose, it is only necessary to so to speak prolong this core, that is to
say, to mount on the shaft, as near as practicable to the armature and on the
opposite side to the commutator, a pulley or bobbin m, called a compensator of
soft iron, of the same diameter and of the same thickness as the core and of a
length equal to the travel of the armature.
By reason of the thickness of the wires of the armature which surround the

page_text: core, the bobbin is not the immediate prolongation of the core; there results
therefrom, during the motion of the armature, a slight discontinuity in the
distribution of the magnetic field. This discontinuity however does not present
any serious inconvenience. Nevertheless, to obviate it completely, it is only
necessary to provide the pole-pieces at this side with slight extensions I, in such a
manner as to cover the space left free between the core and the compensating
bobbin m.
Under these conditions, a very small force is sufficient to move the armature.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. The combination, with the armature shaft of a dynamo-electric or like
machine in which the armature is capable of being displaced relatively to the
pole-pieces, of a
compensator" consisting of a pulley or bobbin of soft iron
arranged adjacent to said armature, substantially as, and for the purposes, herein-
before described.
2. The modification of my invention in which the pole-pieces of the dynamo-
electric machine are provided with lateral extensions, substantially as, and for
the purposes, specified.
Santam nhor 1800.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.
D. YOUNG & Co.,
11 and 12, Southampton Buildings, London, W.C.,
Agents for the Applicant.