An Improvement in Dynamo Electric Machines.
Year: 1892

page_text: Date of Application, 7th Jan., 1892
Complete Specification Left, 30th Sept., 1892-Accepted, 5th Nov., 1892
PROVISIONAL SPECIFICATION.
An Improvement in Dynamo Electric Machines.
We, SIEMENS BROTHERS & Co. LIMITED of 12 Queen Anne's Gate,
Westminster in the County of Middlesex, JOHN NEBEL of 35 Maryon Road
Charlton, and WILLIAM ABRAHAM COLLINGS of 9 Little Heath, Charlton, in the
County of Kent, Electrical Engineers, do hereby declare the nature of this invention
to be as follows:-
This invention relates to dynamo clectric machines of the kind known of the
Siemens alternating current dynamo with disc armature, and has for its object to
simplify the field magnets and render their exciting coils more effective than they
are under their present arrangement. In a machine of the kind referred to an
armature of disc form, having on it ovate coils of insulated wire wound on non-
magnetic cores, revolves between two circular frames, each of which presents towards
the disc a number of pole pieces arranged circularly at equal intervals and having
alternating polarity.
According to the present invention, each of those frames is made of iron with two
circular rows of studs each of approximately rectangular section projecting from its
face. The studs of the one row are farther from the centre than those of the other
row, so that a circular coil of insulated wire can be wound between the inner faces
of the outer studs and the outer faces of the inner studs. To each stud is fixed a
pole piece presenting its face parallel and close to the side of the disc armature, and
these pole pieces, owing to the position of the studs to which they are respectively
fixed, Leing alternately on opposite sides of the one coil, become, when the coil is
traversed by an electrical current, magnet poles of alternating polarity which
induce alternating electric currents in the coils of the armature as they revolve
past them.
Dated this 7th day of January 1892.
ABEL & IMRAY,
Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improvement in Dynamo Electric Machines.
We, SIEMENS BROTHERS & Co., LIMITED, of 12 Queen Anne's Gate,
Westminster, in the County of Middlesex, JOHN NEBEL, of 35 Maryon Road,
Charlton, and WILLIAM ABRAHAM COLLINGS, of 9 Little Heath, Charlton, in the
County of Kent, Electrical Engineers, 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 :-
This invention relates to dynamo-electric machines of the kind known as the
Siemens alternating current dynamo with disc armature, and has for its object to
simplify the field magnets and render their exciting coils more effective than they
are under their present arrangement. In a machine of the kind referred to, an
armature of disc form, having on it ovate coils of insulated wire wound on non-
magnetic cores, revolves between two circular frames, each of which presents towards
the disc a number of pole pieces arranged circularly at equal intervals and having
alternating polarity.
According to the present invention, each of these frames is made of iron with two
circular rows of studs, each of approximately rectangular section, projecting from
its face. The studs of the one row are farther from the centre than those of the
1

page_text: other row, so that a circular coil of insulated wire can be wound between the inner
faces of the outer studs and the outer faces of the inner studs. To each stud is
fixed a pole piece presenting its face parallel and close to the side of the disc
armature, and these pole pieces, owing to the position of the studs to which they are
respectively fixed, being alternately on opposite sides of the one coil, become, when
the coil is traversed by an electrical current, magnet poles of alternating polarity,
which induce alternating electric currents in the coils of the armature as they
revolve past them.
Fig. 1. of the accompanying drawings is a vertical section and Fig. 2 is a front.
view partly in section of one side of a dynamo electric machine of the kind above
referred to with its field magnets arranged according to this invention.
The iron side frame A has on its face the two circular rows of studs B and C,
the studs B at a greater radial distance from the axis than the studs C, so that a
circular coil D of insulated wire is wound inside the studs B and outside the
studs C.
On the studs B and C are fixed pole piece E and F in front of which and very
near to them revolve the ovate coils of the armature, two of which are indicated
at P. When the coil D is traversed by an electric current the studs on its one
side have polarity opposite to that of the studs on its other side, consequently the
pole pieces E which are attached to the studs B are always of polarity opposite to
that of the pole picces F which are attached to the studs C.
Fig. 3 is a section and Fig. 4. a front view of one side of a modified form of
machine with the studs and pole pieces somewhat differently constructed, so that
each pole piece and stud form together a single piece of iron.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
In the Siemens alternating current dynamo electric machine or similar machine
with disc armature, constructing the field magnets by providing on each iron frame
two circular rows of projecting studs with pole pieces having the coil wound in a
circle inside the studs of the one row and outside those of the other, substantially as
described.
Dated this 30th day of September 1892.
ABEL & IMRAY,
Agents for the Applicants.