IMPROVEMENTS IN ELECTRO- MAGNETIC MACHINES
Year: 1869

page_text: LETTERS PATENT to Frederick Hale Holmes, of Mortlake, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN ELECTRO-
MAGNETIC MACHINES."
Sealed the 30th November 1869, and dated the 5th June 1869:
PROVISIONAL SPECIFICATION left by the said Frederick Hale Holmes
at the Office of the Commissioners of Patents, with his Petition, on
the 5th June 1869.
I, FREDERICK HALE HOLMES, of Mortlake, in the County of Surrey,
do hereby declare the nature of my said Invention for "IMPROVEMENTS IN
ELECTRO-MAGNETIC MACHINES," to be as follows:-
This Invention consists, firstly, in making the cores of the helices of
split tubes rivetted into soft iron end plates of such a form that the
plates cover the ends of the coils of wire and project on one side about
2 inches, so as to enable them to be bolted to a brass circular standard
fixed to the base plate of the machine. These end plates have a cut in
them from their edge to the centre corresponding with the split in the
tubes, whereby circular currents are entirely prevented.

page_text: The second part of this Invention (applicable to small machines
requiring not more than 8-horse power to work them) relates to the
mode of coupling up the heliees. According to this part of the Invention,
in a machine of 20 helices, ten alternate helices are all coupled in
series, and the two terminals are fixed to two binding screws. This current
serves for producing light or decompositions. Of the other ten helices
six are coupled up and the terminals fixed to two studs of a "Wheat-
stone's bridge" in such a manner that by inserting the two pins these
six helices alone may send their current through the coils on the electro-
magnets. Two helices are coupled and the terminals fixed to two other
studs of the "bridge" in such a manner that by changing the positions
of the pins these eight helices shall pass their combined current through
the coils on the electro-magnets; in the same manner the remaining
two helices are arranged so that 6, 8, or 10 helices may be used
for magnetizing the electro-magnets, which will vary the power required
to turn the machine from 3 to 5 or 8 horse power.
The third part of this Invention, which also relates to small machines,
consists of a peculiar manner of fixing the electro-magnets. Five soft
iron electro-magnets of the horse-shoe form are bolted on each side of a
hollow brass boss, which is firmly keyed on to the shaft of the machine
by brass bolts passing through from side to side, and the magnets are
secured in their places by nuts on the ends of these bolts. The poles of
all the magnets are so arranged that the 10 on each side are exactly
facing one another, and are equidistant in each ring. The distance
between the inner surfaces of the two rings of magnets is about th of an
inch greater than the length of the helice cores, giving about th of an
inch clearance on each side of the helix ring; but as the enormous force
of the electro-magnets would bend in the poles and bring them in con-
tact with the helices, I insert. between the two rings of electro-magnets
a broad brass hoop about th of an inch thick. This hoop is let into a
groove turned in each ring of electro-magnets, and serves the double
purpose of preventing the poles being bent inwards by the attrative
force, and of preventing the coils on the electro-magnets from flying off
by centrifugal force, Further, to secure more effectually these two enda
on which the stability of the machine greatly depends, I fix to the
outside of each ring of electro-magnets a brass disc of such a form that
it serves as the brass hoop does to maintain the coils on the electro-
magnets in their places, and by being extended to the extremities of the

page_text: poles, and screwed to each pole near to the outer ends, assists also in
preventing the poles from being drawn inwards.
The fourth part of this Invention consists in fixing against the core
plates on each side of the helix ring a ring of copper or other suitable
metal made flat on the side next to the helix plates, so as to be in good
contact therewith. This ring is hollow, and whilst the machine is in
use cold water is made to circulate constantly through it for the purpose
of carrying off the heat which is produced or generated in the cores and
plates by their violent successive changes of magnetic state.
The fifth part of this Invention consists in making a commutator of
such a form as regards the shape of the teeth that each of the two rollers
in passing over the teeth shall be in contact with two teeth at the same
time, so as to make short circuit for one-fourth or thereabouts of the
time of passing one tooth; or I make the commutator of the usual form,
and make short circuit by means of a metallic rubber kept constantly
in contact with the surface of the commutator by means of a spring.
This rubber is placed in such a position that when the rollers pass over
a division in the commutator this rubber may pass at the same time,
and by its breadth make short circuit for about one-fourth the time the
rollers take to pass over a tooth.
The sixth part of this Invention consists in having holes in the hollow
boss close to the shaft by which air is allowed to enter when the machine
is at work, and other holes in the cylindrical part of the boss and in the
brass hoop to allow the air to circulate freely amongst all the coils for
the purpose of keeping them cool.
The seventh part of this Invention relates to a novel arrangement of
electro-magnets and helices for large machines when low speed is
required, or when more than one light is required from the same
machine. According to this part of the Invention I arrange the halices
for a machine of, say, two lights, thus the helice ring is of a size capable
of holding 44 helices, 48 only of which are mounted in it, leaving on
each side of a series, of say, 13 helices a space equal to half that
occupied by a single helix, so that when 30 of the poles of the. electro-
magnets are exactly over the cores of 30 helices 12 will be exactly mid-
way between the centres of these 13 helices.. The 30 helices are divided
into two series of 15 helices each, and are coupled up not as in the small
machines before described, but each. helix to the next in succession

page_text: throughout the 15, the terminals being fastened to binding screws.
Each 15, helices will give a very powerful light, The thirteen are used for
magnetizing the electro-magnets, and may be coupled up as one series,
or, if desired to vary the power of the light and consequently the power
required to drive the machine, they may be coupled up in two or more
series, as, for example, in a series of 8, 3, and 2, or 10 and 3, the
terminals being arranged as before described.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederick Hale Halmes in the Great Seal Patent
Office on the 3rd December 1869,
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
HALE HOLMES, of Mortlake, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of June, in the year of our
Lord One thousand eight hundred and sixty-nine, in the 32nd year of
Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Frederick Hale Holmes, Her special license that I
the said Frederick Hale Holmes, my executors, administrators, and
assigns, or such others as I, the said Frederick Hale Holmes, my
executors, administrators, or assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise,,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN ELECTRO-MAGNETIC MACHINES," upon the condition (amongst others) that
I, the said Frederick Hale Holmes, his executors or administrators, by
an instrument in writing under my hand and seal, should particularly
describe and ascertain the nature of the said Invention, and in what
nianner the same was to be performed, and cause the same to be filed
the Great Seal Patent Office within six calendar months next and
Immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Frederick Hale Holmes, do hereby
déclare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and

page_text: by the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say:
My said Invention consists, firstly, in making the cores of the helices
of split tubes rivetted into soft iron end plates of such a form that
the plates cover the ends of the coils of wire and project on one side
about two and a half inches so as to enable them to be bolted to a brass
circular standard fixed to the base plate of the machine. These end
plates have a cut in them from their edge to the centre corresponding with
the split in the tubes whereby circular currents are entirely prevented.
The second part of this Invention (applicable to small machines
requiring not more than eight-horse power to work them) relates to the
mode of coupling up the helices. According to this part of the
Invention in a machine of twenty helices, ten alternate helices are all
coupled in series and the two terminals are fixed to two binding screws:
This current serves for producing light or decompositions. Of the other
ten helices six are coupled up and the terminals fixed to two studs
of a Wheatstone's bridge" in such a manner that by inserting the
two pins these six helices alone may send their current through the
coils on the electro-magnets. Two helices are coupled and the terminals
fixed to two other studs of the "bridge" in such a manner that by
changing the positions of the pins these eight helices shall pass their
combined current through the coils on the electro-magnets in the same
manner, the remaining two helices are arranged so that six, eight, or
ten helices may be used for magnetizing the electro-magnets which
will vary the power required to turn the machine from three to five
and a half or eight horse power.
The third part of this Invention which also relates to small machines.
consists of a peculiar manner of fixing the electro-magnets. Five soft
iron alectro-magnets of the horse-shoe form are bolted on each side of
a hollow brass boss which is firmly keyed on to the shaft of the machine
by brass bolts passing through from side to side, and the magnets are
secured in their places by nuts on the ends of these bolts. The poles
of all the magnets are so arranged that the ten on each side are exactly
facing one another and are equidistant in each ring. The distance
between the inner surfaces of the two rings of magnets is about one-
eighth of an inch greater than the length of the helice cores, giving
about one-sixteenth of an inch clearance on each side of the helix

page_text: ring; but as the enormous force of the electro-magnets would bend in
the poles and bring them in contact with the helices I insert between
the two rings of electro-magnets a broad brass hoop about one-eighth
of an inch thick. This hoop is let into a groove turned in each ring
of electro-magnets and serves the double purpose of preventing the poles
being bent inwards by the attractive force and of preventing the coils
on the electro-magnets from flying off by centrifugal force. Further,
to secure more effectually these two ends on which the stability of the
machine greatly depends, I fix to the outside of each ring of electro-
magnets a brass disc of such a form that it serves as the brass hoop
does to maintain the coils on the electro-magnets in their places and
by being extended to the extremities of the poles and screwed to each
pole near to the outer ends, assists also in preventing the poles from
being drawn inwards.
The fourth part of this Invention consists in fixing against the core
plates on each side of the helix ring a ring of copper or other suitable
metal made flat on the side next to the helix plates so as to be in
good contact therewith. This ring is hollow and whilst the machine
is in use cold water is made to circulate constantly through it for the
purpose of carrying off the heat which is produced or generated in
the cores and plates by their violent successive changes of magnetic
state.
The fifth part of this Invention consists in making a commutator of
such a form as regards the shape of the teeth that each of the two
rollers in passing over the teeth shall be in contact with two teeth at
the same time so as to make short circuit for one-fourth or thereabouts
of the time of passing one tooth, or I make the commutator of the
usual form and make short circuit by means of a metallic rubber kept
constantly in contact with the surface of the commutator by means
of a spring. This rubber is placed in such a position that when the
rollers pass over a division in the commutator, this rubber may pass at
the same time, and by its breadth make short circuit for about one-
fourth the time the rollers take to pass over a tooth. When I use
rubbers on an ordinary commutator in lieu of rollers I prefer to wind
'the helices which serve to magnetise the electro-magnets with six or
more fine wires insulated throughout the series and terminating in a
corresponding number of insulated rubbers. By this means I preserve
the commutator from the destructive effect produced by so powerful

page_text: a current when undivided. When using this arrangement of wires the
"Wheatstone's bridge" herein-before referred to must be so arranged
that each wire of the number used shall have a distinct pair of terminals
on the box so that each pin when inserted shall pass the current of
each wire to its corresponding rubber without destroying the insulation.
The sixth part of this Invention consists in having holes in the hollow
boss close to the shaft by which air is allowed to enter when the machine
is at work, and other holes in the cylindrical part of the boss and in the
brass hoop to allow the air to circulate freely amongst all the coils for
the purpose of keeping them cool.
The seventh part of this Invention relates to a novel arrangement
of electro-magnets and helices for large machines when low speed is
required or when more than one light is required from the same
machines. According to this part of the Invention I arrange the
helices for a machine of, say, two lights, thus the helix ring is of a
size capable of holding 44 helices, 43 only of which are mounted
in it leaving on each side of a series, say, of thirteen helices a
space equal to half that occupied by a single helix, so that when
thirty of the poles of the electro-magnets are exactly over the cores
of thirty helices twelve will be exactly midway between the centres
of these thirteen helices. The thirty helices are divided into two series
of fifteen helices each and are coupled up not as in the small machines
before described, but each helix to the next in succession throughout
the fifteen, the terminals being fastened to binding screws. Each fifteen
helices will give a very powerful light. The thirteen are used for
magnetizing the electro-magnets and may be coupled up as one series,
or, if desired to vary the power of the light and consequently the power
required to drive the machine, they may be coupled up in two or more
series, as, for example, in a series of eight, three, and two, or ten and
three, the terminals being arranged as before described.
And in order that my said Invention may be fully understood I shall
now proceed more particularly to describe the same and for that purpose
shall refer to the several Figures on the annexed Sheet of Drawings,
the same letters of reference indicating corresponding parts in all the
Figures.
Figure 1 of my Drawings represents a side view and Figure 2 a front
view of my improved helix core for electro-magnetic machines in which
the helices are fixed and the magnets revolve, but in the case of the

page_text: magnets being fixed and the helices revolving the projecting part of
the plates would be radially inwards instead of outwards, as shewn.
Figure 3 represents the method of coupling the helices in machines,
say of 20 helices. Ten alternate helices are joined in series, as shewn,
and the terminals end at L', L, (Figures 3, 4, 7, and 8,) six of the
remaining ten are joined and their terminals end in their studs 1
and 6 (Figures 3, 4, and 7), two others terminate in the studs 2 and 3
(Figures 3, 4, 7), and the remaining two terminate in the studs 4 and 5
(Figures 3, 4, 7). When only six of these helices are required to
magnetize the electro-magnets a connecting pin is inserted between the
studs 1 and D and another between 6 and A (Figure 4), when eight
are required a pin is inserted between 5 and 6 and another pin
between 4 and B (Figure 4), and the pin that was between 6 and A
is then removed. When ten are required to be used a pin is inserted
between 4 and 3 and another pin between 2 and C and then the pin
between 4 and B (Figure 4) is to be removed. The studs A, B, C, are
in .contact with the roller of the commutator O, and the studs D, E, F,
with the roller O¹ (Figures 4, 7, and 8).
Figures 5 and 6 shew the manner in which the electro-magnets are
fixed to the boss. In each of these Figures one brass disc is removed
in order that the arrangement of the electro-magnets may be better
seen; Figure 5 is a front view and Figure 6 is a section through 1-2,
(Figure 5); G, G, are the electro-magnets surrounded with their coils
H, H, they are maintained in their places, first, by strong brass bolts j,j,
which pass through the boss and serve to hold the two rings of
magnets K; (Figures 5 and 6) is a brass hoop let into the electro-
magnets about one-eighth of an inch. This hoop serves to maintain the
distance between the poles and also serves to prevent the coils flying
off the brass disc. The plate M also serves the same purposes. This
disc is screwed to the magnets at N, N. The coils on the electro-
magnets are all connected in series and the terminals pass through a
hole bored in the shaft to the commutator one terminal being fixed to
each of the two rings of the commutator.
Figure 7 is a front elevation of a complete machine of twenty helices,
and Figure 8 is a side elevation of the same. The means employed to
carry off the heat generated in the cores of the helices is shown at P,
Figures 7 and 8, it consists of a circular ring of copper, flat on the
side next the helix plate; on the outer side another piece is soldered

page_text: to this flat ring so as to form with it a half round tube. A union is
soldered into this half round tube at its lower part 9 (Figure 7) by
which cold water is made to enter; another union » (Figures 7 and 8) at
the top of the tube enables the heated water to pass off. There are two
of these rings to each machine one on each side, as shown in Figure 8
at P, P.
Figures 9 and 10 shew the new form of commutator for an electro-
magnetic machine of twenty helices. The teeth in each ring are of
the same form, that is of the form shewn at R (Figure 9) and as the
rollers are the full width of the part from x to y they will be in contact
with the two rings at one time and thus make short circuit while
passing over the parts overlapping as at from u to z; Figure 10 is a
front view of the same commutator on its vulcanite insulator. In the
boss to which the electro-magnets are bolted holes are bored both in
the sides as shewn at S (Figure 5) and in the cylindrical part also
at S (Figure 6). Again in the brass hoop K (Figures 5 and 6) there
are holes bored at intervals all round so that a free current of air passes
amongst all the coils, both those on the electro-magnets and those
forming the helices, to keep them cool.
The Figures 1, 2, 9, and 10 are drawn half size, the remaining Figures
are drawn one-eighth the full size.
Having now described and particularly ascertained the nature of my
said Invention, and the manner in which the same is or may be
used or carried into effect, I would observe in conclusion that what I
consider to be novel and original, and therefore claim as the Invention
secured to me by the herein-before in part recited Letters Patent is,―
First. The combination of split tubes with soft iron end plates
arranged substantially as and for the purpose herein-before described
under the first head of my Invention.
Second. The peculiar mode of coupling up the helices, substantially
as herein-before described under the second head of my Invention.
Third. The combination with the electro-magnets of the hollow brass
boss the brass hoop for adjusting the distance between the poles of the
magnets and for maintaining the coils in their places together with
the outer brass disc, the whole being arranged substantially as and for
the purpose herein-before described under the third head of my Invention
and illustrated by my Drawings.

page_text: Fourth. The application of a hollow copper ring to each side of the
helix ring for the circulation therethrough of cold water during the
working of the machine, substantially as herein-before described.
Fifth. The peculiar form and arrangement of the teeth of the com-
mutator when used in combination with rollers, substantially as and
for the purpose herein-before described under the fifth head of my
Invention.
Sixth. The peculiar arrangement and mode of coupling up the helices
of large machines intended to work at low speeds as herein-before
described under the sixth head of my Invention.
In witness whereof, I, the said Frederick Hale Holmes, have to
this my Specification set my hand and seal, this First day of
December One thousand eight hundred and sixty-nine.