IMPROVEMENTS IN MAGNETO-ELECTRIC AND DYNAMO-ELECTRIC MACHINES, PARTS OF WHICH IMPROVEMENTS APPLICABLE ALSO TO OTHER PURPOSES."ARE
Year: 1880

page_text: LETTERS PATENT to Desmond Gerald Fitz Gerald, of Brixton, in the County. of
Surrey, Electrician, for an Invention of "IMPROVEMENTS IN MAGNETO-ELECTRIC
AND DYNAMO-ELECTRIC MACHINES, PARTS OF WHICH IMPROVEMENTS
APPLICABLE ALSO TO OTHER PURPOSES."
ARE
PROVISIONAL SPECIFICATION left by the said Desmond Gerald Fitz Gerald
at the Office of the Commissioners of Patents on the 28th February 1880.
DESMOND GERALD FITZ GERALD, of Brixton, in the County of Surrey, Electrician.
"IMPROVEMENTS IN MAGNETO-ELECTRIC AND DYNAMO-ELECTRIC MACHINES, PARTS
OF WHICH IMPROVEMENTS ARE APPLICABLE ALSO TO OTHER PURPOSES."
My Invention relates to improvements in magneto-electric or dynamo-electric
machines, and principally to that class of machine which is constructed with a ring
of soft iron carrying coils of wire.
This ring is ordinarily made to rotate between the poles of a permanent magnet
or an electro-magnet (or magnets) of very considerable dimensions relatively to the
ring.
According to my Invention I substitute for these large magnets comparatively
small permanent or electro magnets arranged in the plane of the ring, and in one
form of my Invention nearly surrounding the ring and its coils. The magnets
thus partially surrounding the soft iron ring are preferably compounded of several
bars or plates forming part of a hollow ring, and constitute permanent or electro
magnets. Four such magnets or systems of magnets may be used, two of them
baving their similar poles opposed at one portion of the ring, and the other two
having their similar poles (of contrary polarity to the former) opposed at another
portion of the ring diametrically opposite to the former portion. The currents
from the coils about the ring are collected at the two opposite points of the ring
which are situated between the opposed poles of opposite polarity of the surrounding
magnets or systems of magnets. More than four such coils or systems of coils may
be used if desired.
Instead of the permanent or electro magnets or systems of magnets forming
portion only of a hollow ring partially enclosing the soft iron ring and its coils, I
sometimes use coils of wire entirely surrounding tho soft iron ring and its coils.
The ring in this case has its coils enclosed in a casing of soft iron, and is mounted
upon three or more revolving supports at its periphery, and is made to rotate by a
belt or other means in connection with a prime mover.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Desmond Gerald Fitz Gerald in the Great Seal Patent Office on the
28th August 1880.
DESMOND GERALD FITZ GERALD, of Brixton, in the County of Surrey, Electrician.
"IMPROVEMENTS IN MAGNETO-ELECTRIC AND DYNAMO-ELECTRIC MACHINES, PARTS
OF WHICH IMPROVEMENTS ARE APPLICABLE ALSO TO OTHER PURPOSES."
This Invention relates to improvements in magneto electric and dynamo electric
machines, and principally to that class in which a ring of soft iron carrying coils of
wire is rotated between the poles of a magnet, electro or permanent. According to
my Invention instead of rotating the ring with its coils between the poles of a
magnet on the ordinary system I employ maguets, electro or permanent, either
wholly or partially surrounding the ring, both longitudinally and transversely.
The ring is thus magnetized directly and with the least possible loss, and the
direction of the inducing magnetic polarity is in the circle constituted by the ring
itself, as it should be. The machine thus constructed is, amongst other advantages
of minimum bulk and weight, cheaply constructed and of maximum effectiveness.
One part of my Invention is illustrated at Figs. 1 to 5 of the accompanying
Drawings (which Drawings are to be taken as part of this Specification), reference
being had to the letters and figures marked thereon, like letters indicating like
parts. Fig. 1 is a transverse sectional elevation of a dynamo electric machine
constructed according to my Invention, and Fig. 2 is an elevation thereof, partly in
section, looking on to the left hand side of Fig. 1, with the driving pulley removed.
A is the soft iron ring carrying 60 (more or less) coils B of wire, all wound in one
direction. The ends of these coils are attached to a collector C, as more fully
hereinafter described. Ring A with its coils is mounted on a disc D attached by
boss E to shaft F mounted in suitable bearings on standards G, and carrying on
one end driving pulley H for giving rotary motion to ring A. This ring A is
almost wholly surrounded by a hollow clectro magnetic ring I, 11, 12, i.c., the luttor
surrounds the ring A both longitudinally and transversely. For convenience of
manufacture the ring I, I', 12, is divided into several portions, of which two, I¹
and I, are annular and two are semi-annular, and make up the section of largest
dinmeter I, the division between the halves being by preference at top and bottom.
The separate portions of this hollow magnetic ring are so wound with coils of wire
as to constitute two magnets, having their like poles opposed on the vertical plane
transverse to the ring A. The reverse direction of the winding near the poles
requisite to produce this effect is shewn at Fig. 3. The various sections of the
electro magnetic ring are united and held in position by thin lugs J projecting
from their cores between the coils of wire, these lugs being bolted to other lugs K
cast on the framing L. The ring A has preferably a deep recess a cut in it
circumferentially, as shewn. The extremities of the coils on ring A are, as before
stated, connected to collector C. This consists of a cylinder C of wood or other
non-conducting material screwed or otherwise rigidly attached to boss E, and
having let flush into its inner circumferenco a series of strips M of conducting
metal insulated and equal in number to the coils on ring A. The extremities of
the coils are brought to the outside of collector A and connected so as to constitute
a closed circuit, the points of connection between adjacent coils being severally
brought into contact with the conducting pieces M, as shewn at m, m. The current
is taken off at the horizontal central line, i.e., the line of greatest polarity, by two
frictional contact pieces diametrically opposed, and seen clearly at Fig. 4, which
presents a face view of collector C. These frictional contact-pieces consist each of
a series of flat springs O¹ of copper or other suitable material, each spring bearing
at its extremity the frictional contact piece of metal O, and so that all these pieces
will impinge on the inner circumference of C at the same time, and all the springs

page_text: bo in slight tension. The springs are attached at their other extremities to a round
bar P, which passes through a terminal and may be fixed therein in position
by set screw R. On the end of bar P is fastened a short lever S having an
adjusting screw S₁ tapped through it, and bearing against the plate underneath.
By this screw any required tension may be put on to springs O', thus regulating
the friction between contact pieces O and inner circumference of C. Terminal Q is
fixed to and insulated from a plate T attached by screw U to the end standard of
the machine. By removing this screw the whole of the parts of the current-taking
mechanism may be directly removed.
Another part of my improvements relates to the construction of ring A (see
Fig. 5). In winding a number of coils of wire upon a ring, more especially if it be
of circular section, and if the number of turns of wire be the same in each layer,
interstices are left between the coils. These interstices I fill with'soft iron blocks V
with considerable advantage. These blocks or collars are placed radially on the
ring, their sides tapering inwards towards the centre of the ring, and leaving
between the blocks spaces radially placed but with parallel sides for the coils.
These blocks V may either be cast with the ring or made separately and slipped on,
the ring being constructed in halves to receive them, as shewn.
Figure 6 shews a central sectional elevation of a modified form of the ring A
and encircling inagnets I, I, 12, the ring being a hollow cylinder instead of being
of circular sectiou, and the encircling magnets being modified in shape accordingly.
In principle they are identical with the circular ring and magnets previously
described. In this form of machine I sometimes dispense with the inner encircling
portion of the inducing magnets, making the latter simply a cylinder surrounding
the exterior of ring A.
Figs. 7 to 10 illustrate a form of my machine in which the ring A is wholly
encircled on its cross section by coils W of wire in lieu of inducing magnets. These
encircling coils W are supported in suitable framing X, and the ring A to rotate
thro' them is mounted between three or more rollers Y, by one of which (preferably
the upper) it is driven by frictional contact, the surface of this roller or pulley
being of india rubber, as seen at i, i, Fig. 8. The extremities of the coils of ring A
are attached in the manner before described to a series of strips of conducting
metal Z let flush into the external surface of an ebonite or wooden ring A' fitted
round the outside of ring A. The current is taken off (in a manner similar to that
before described) at an aperture in the outer circumference of the coils W left in
cach between the wires. 1 prefer not to wind the coils W as complete circles.
They are wound so as to leave a longitudinal groove W on their inner surfaces
where they pass over the ring A¹ on the outside of ring A. This allows of the
two surfaces of the ring and encircling coils being brought into very near contact.
Fig. 8 is a transverse section taken at a, b; Fig. 9 is a sectional plan of ring A
at centre-line; and Fig. 10, a section of coils W taken at line c, d, Fig. 7.
It is obvious that in the three forms of machines shewn permanent magnets
may be substituted for the electro-magnets, the permanent magnets retaining
substantially the same shape, but being necessarily divided at the points where
thoir similar poles are opposed.
The coils on the ring A and those on the inducing electro-magnets I, II, 1, (or
the inducing coils W) may be connected in mutiple are or in series, as is well
understood.
The apparatus may be advantageously constructed in duplicate, the current from
one of the rings A being employed to magnetise both of the hollow electro-magnetic
rings, and the current for the external portion of the circuit being taken from the
second ring A.
I sometimes enclose the coiled ring A in a casing of soft iron provided with a
circumferential slot to allow of the passage of the wires from the coils.
The arrangement of the inducing magnets I, I, I, and the coils W is applicable
to ring armatures generally, and other than such as hereinbefore described. The

page_text: saddle-back magnets described of double or single curvature are applicable to a
variety of purposes.
I claim as my Invention to be secured by the hereinbefore in part recited Letters
Patent,-
1. In dynamo or magneto electric machines, the combination with a ring or
cylinder shaped armature of permanent or electro-magnets of double curvature,
such as will encircle the ring armature both longitudinally and transversely,
substantially as hereinbeforo setforth and described, and illustrated in the
accompanying Drawings.
2. In similar machines, the combination with a ring or cylinder-shaped armature
of an electro or permanently magnetic ring constituting two magnets, having their
similar poles opposed in a plane transverse to the ring-armature, substantially as
described in reference to Fig. 6 of the accompanying Drawings.
3. In similar machines, the combination with a revolving coiled ring or cylinder
of stationary inducing coils completely encircling the revolving coiled ring or
cylinder, substantially as hereinbefore setforth and described, and illustrated in
Figs. 7 to 10 of the accompanying Drawings.
4. Constructing dynamo and magneto-electric machines, substantially as described
and illustrated in the accompanying Drawings.
5. The construction for use in dynamo or electro-magnetic machines or in other
electrical apparatus of magnets of the nature herein before referred to in reference
to the machines illustrated in Figs. 1 to 6 of the accompanying Drawings, the
essential characteristic of such magnets (termed by me saddle-back magnets) being
that they are always curved in the direction transverse to the axis of the magnet
(or the line joining the poles), whilst they are sometimes curved also in the
direction of this axis, and in the case of electro-magnets are surrounded with coils
of wire, every turn of which is partly convex and partly concave.
In witness whereof, I, the said Desmond Gerald Fitz Gerald, have hereunto
set my hand and seal, this Twenty-eighth day of August, in the year of
our Lord One thousand eight hundred and eighty.
DESMOND G. FITZ GERALD. (L.S.)
Witness,
J. H. BLAND,
Clerk to J. W. Gray, C.E.,
Patent Agent,
27, Southampton Buildings,
London, W.C.