IMPROVEMENTS IN ELECTRC-MAGNETIC AND MAGNETO-ELECTRIC MACHINES
Year: 1868

page_text: LETTERS PATENT to Frederic Hale Holmes, of Gravesend, in the
County of Kent, Engineer, for the Invention of "IMPROVEMENTS IN
ELECTRC-MAGNETIC AND MAGNETO-ELECTRIC MACHINES."
Sealed the 15th December 1868, and dated the 26th June 1868.
PROVISIONAL SPECIFICATION left by the said Frederic Hale Holmes
at the Office of the Commissioners of Patents, with his Petition, on
the 26th June 1868.
I, FREDERIC HALE HOLMES, of Gravesend, in the County of Kent,
Engineer, do hereby declare the nature of my said Invention for
"IMPROVEMENTS IN ELECTRO-MAGNETIC AND MAGNETO-ELECTRIC MACHINES," to be
as follows:-
My Invention consists, firstly, of a new form of permanent or electro-
magnet which is formed of two hollow discs, that is, hollowed on onc
side and rounded on the other; from the edges of these circular discs
project radial arms at such distances apart that when the two discs are
brought near to one another the arms shall not be too near each other.
These arms are bent on leaving the disc, so that when the two discs are
Γ

page_text: fixed on a shaft at a certain distance apart the arms form a ring of poles
alternately north and south and are in one plane. These magnets may
be made of steel, or cast or wrought iron, or of any combination or
mixture of metals capable of being converted into magnets.
A permanent magnet formed as above described is to be magnetised by
making the centre of the disc one pole and all the arms the other pole,
then two discs so magnetised (only with the arms in each disc of an
opposite polarity and mounted on a shaft), will form but one compound
magnet with all the radial arms alternately north and south.
For making an electro-magnet of the above form the discs are made of
soft iron, cast iron, or other metal capable of becoming magnetised of the
same form as above, and when mounted on their shaft the hollow space
formed between the discs is filled with or partly filled with insulated
copper or other wire wound around the axis or shaft and parallel with
the sides of the discs; but when more powerful effects are required the
wire is wound also on the outside of the discs as well as between any
two sets of them. These coils of wire whatever may be their number
are all to be connected with one another in such a manner that the
current of electricity passing through the whole will produce the
polarity of the magnets as desired, and are finally connected with a
commutator.
Secondly. In new forms of helices or bobbins I make the cores in one
form of two pieces of half-round iron, or two pieces of iron having a
flat side; each of these pieces is attached at both extremities to two
iron plates of such a form that when the two pieces forming the cores
are placed together with an insulating substance between them the two
plates shall not touch at each side or end of the cores, but shall show a
clear split from end to end and radial to the centre. The plates are of
such a size as to cover the ends of the coils of wire to be wound on the
cores and project on the outer part from the centre sufficiently to be
screwed on a brass or gun metal ring. These cores with their plates
may be made either of wrought or cast iron.
Another form of helix may be made with the split cores with the
plates only attached to one end, the other ends of the cores being fixed
in an iron ring or plate.
When great intensity is required I construct another form of helix as
follows: I make the cores of bundles of straight iron wires, the ends
of these cores being fastened into iron plates, but not split as above

page_text: described. Around the cores I wind stout insulated copper wires which
are all connected and pass to a commutator fixed on the shaft of the
machine; outside of these stout wires, which form a primary coil or series
of primary coils, I wind a secondary coil or series of secondary coils of
insulated fine wire; or I use two sets of bobbins or helices in the same
machine, one set being constructed of stout wires and the split cores as
above described for the purpose of magnetizing the electro-magnets
when electro-magnets are employed, or if permanent magnets are used
in the machine I do not require these stout wire helices, but in that case
only one set of helices, which I call "intensity coils," made of fine
insulated copper wire wound directly on the iron wire cores above
described. Coils more or less intense have been previously employed in
the construction of magneto machines, but my "intensity coil" differs
from these in this, that the intensity in mine is sufficient to flash
through space between the terminals.
In making magneto-electric or electro-magnetic machines with the
magnets and helices of the forms herein-described I prefer to fix the
helices to fixed rings and the magnets to the shaft; but I do not intend
to confine myself to this form of machine as the same improved forms
may be applied in either case, neither do I intend to confine myself to
any number of magnets on the shaft, or size of the magnets, or number
of rings of helices.
Thirdly. In a new form of commutator to suit the helices made with
the secondary coils. This new commutator is of the same form as that
for which Letters Patent were granted to me on the 14th day of October
1857, No. 2628, only that half of each tooth is cut away parallel with
the shaft and the space filled with vulcanite or other insulating substance,
and the rollers which pass over the teeth and spaces are so arranged that
the primary current shall be completely broken at the time when the
greatest quantity of electricity is developed in the helices, thus causing
it to pass through the secondary coils.
Fourthly. In having a current changer fixed in the course of the
wires between the commutator and the coils round the electro-magnets.
by means of which the whole of the electricity in these coils can be
discharged to any given point, and may be used for blasting in mines and
other similar purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederic Hale Holmes in the Great Seal Patent
Office on the 23rd December 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
HALE HOLMES, of Gravesend, in the County of Kent, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-sixth day of June, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-second
year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Frederic Hale Holmes, Her special license
that I, the said Frederic Hale Holmes, my executors, administrators,
and assigns, or such others as I, the said Frederic 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
ELECTRC-MAGNETIC AND MAGNETC-ELECTRIC MACHINES,'
upon the condition
(amongst others) that I, the said Frederic Hale Holmes, my 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 manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
IN
NOW KNOW YE, that I, the said Frederic Hale Holmes, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
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, of a new form of electro-magnet
composed of two discs, both of which are hollowed on one side and
rounded or made convex on the other; from the edges of these discs
project arms which are placed at such distances apart that when the
two discs are brought with their concave sides facing and near to each

page_text: other, the arms will not be too close. These arms are curved or so applied
to the discs that when the latter are fixed on a shaft and at a certain
distance they form a ring with poles alternately north and south and
are in the same plane. These electro-magnets may be manufactured
of steel, or wrought or cast-iron, or of any mixtures or combinations of
metals susceptible of being converted into magnets.
The permanent magnets formed in the manner herein-before described
are magnetized by rendering the centre of the disc one pole and the
several arms the other pole, but so as to give the arms in each disc an
opposite polarity, the combined magnetized discs forming a compound
magnet of which the several radial arms are alternately north and
south.
In order to produce an electro-magnet composed of discs of the form
above-described it should be made of wrought iron, cast iron, or any
other metal susceptible of being magnetized, and when it is mounted
on its shaft the void space between the hollow faces of the disces is
fitted either wholly or partially with an insulated copper or other wire
which is wound on the axis or shaft parallel to the sides of the disc.
When it is required to obtain the most powerful effects the wire is wound
also on the exterior or against the convex faces of the discs. The coils of
wire, whatever their number may be, are all arranged in such a manner
that an electric current passing through the whole may produce the
desired polarity of the magnets, the two terminals being finally connected
to a commutator.
My Invention consists, secondly, of certain new forms of helices or
coils, the cores of which I make of two pieces of half round iron, or
of two pieces of iron having a flat side. Each of these pieces is attached
at both ends to two iron plates of such a form that when the two
pieces which constitute the cores are placed together, but with an
insulating substance between them, there will be a clear radial slot from
end to end of the two plates at each end of the cores. The plates are of
sufficient size to cover the extremities of the wire coils which are to be
wound on the cores and project at the external part of the centre
sufficiently to be screwed on to a ring of gun metal or other suitable
metal. The cores and their plates may be made either of wrought or
cast-iron.
Another form of helix may be made with cores split two-thirds of
their length and a plate attached simply at one end, the other end

page_text: of the cores being fixed in a ring of gun metal with thin iron plates
connecting each pair.
When great intensity is required I construct another form of helix
in the following manner:-The cores are made with bundles of thick
iron wire and their extremities are maintained in iron plates, but such
plates are not split like those herein-before described. I wind round
the cores thick insulated copper wires which proceed to a commutator
fixed on the shaft on the machine; outside these thick wires, which form
a primary series of helical coils, I wind spirals in a volute form of fine
insulated wire. Two classes of coils or helices may be employed in the
same machine, the one formed of very stout wire and the cores as
herein-before described with a view to magnetize the electro-magnets
when the latter are employed; but when permanent magnets are used
I do not employ helices formed of stout copper wires; in this case 1
simply employ a set of helices, which I call intensity helices, formed of
a fine insulated copper wire wound in a spiral or volute form directly
on the cores of iron wires herein-before described. Helices of greater
or less intensity have been previously employed in the construction of
magnetic machines, but my intensity helices differ from the former in
this, that the intensity in my helices is sufficient to cause a spark or
flash to pass through the space between the extremities of the coils.
In constructing magneto-electric or electro-magnetic machines with
magnets and helices made in the manner herein-before described I
prefer to fix the helices to the fixed rings and the magnets to the shaft;
but I wish it to be understood that I do not confine myself to this
method of construction, as the same improved arrangements may be
applied in other conditions. I also reserve to myself to apply any
number of magnets on the shaft, and to make the magnets of any
dimensions and to vary the number of rings of the helices.
The third part of my Invention relates to an arrangement of commu-
tator which is used with the primary and secondary coils or the simple
intensity coils and ordinary coils herein-before described; this commutator
has half of each tooth cut away in a direction parallel to the axis, and
the space is filled with hard india-rubber or any other good insulating
material, and the rollers or rubbers which pass over the teeth and
the insulating spaces are so arranged that the primary current will be
interrupted at the moment when the greatest quantity of electricity is

page_text: developed in the helices, forcing it thus to pass through the secondary
helices or coils.
The fourth part of my said Invention consists in having a current.
changer fixed in the circuit of the wires between the commutator and
the coils around the electro-magnets, by means of which all the electricity
of the coils round the electro-magnets may be discharged at any given
point and be employed to produce an explosion in mines for example
and for other similar purposes.
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
corresponding Figures.
Figure 1 of the Drawings is an end elevation of my improved machine
mounted, and Figure 2 is a corresponding longitudinal section of the
same. The new form of the magnets is shewn at C₁, C³, C³, C'.
Figure 3 shows a slight modification of the same, which when employed
as a permanent magnet consists of arms N1, N2, of steel welded to a
disc of soft iron; the same arrangement produces a more powerful electro-
magnet of the said arms are of wrought iron and the helices wound
round the bosses, as shewn at D, Figure 2. In either case all the poles
of the arms of one disc are of the same denomination, and all those of the
other disc are of an opposite denomination, and they form when
combined a complete magnet, so that when they are in their place
the poles are alternately north and south; these discs are fixed on the
main shaft by the bosses o. The helices of one of the improved com-
binations are shewn at F (Figure 1) and also in enlarged detail at
Figure 4, where P and Q represent respectively a front and side elevation
of the core, which consists of two pieces of half-round iron secured at
their extremities to the two parts of an iron plate; an insulating material
is placed between the two parts so as to separate them throughout their
length as shewn.
Figures 1 and 2 show a machine capable of producing a very
powerful electric light, but by the aid of an arrangement which I am
about to describe the quantity of light and the degree of corresponding
force to cause the magnets to turn may be modified without stopping the
machine. The coils of the helices G are brought together, as shewn in
Figure 6. The ends of the wires of each series of helices are united on

page_text: the metal blocks u (shown also in Figure 1), and further indicated by the
numerals 1, 2, 3, 4, 5, and 6 (in Figure 6), and all the blocks marked x
(Figure 6) are in communication with one of the rubbers m (Figure 1)
of the commutator L, and those marked a¹, with the other rubber m', as
shown clearly in Figure 6; then if a plug or stopper be placed between
1 and (Figure 6), and another between 2 and x, the currents from
four of the helices G will pass into the coils around the electro-magnets,
but if these plugs are removed and replaced in the holes between 1 and 1¹
and the others between 2 and 2₁, after having put two other plugs
between 3 and x' and 4 and x, then the currents from the eight helices G
will pass to the magnetic coils and as will be well understood on
examining the diagram the currents of the four, six, eight, ten, or twelve
helices may be employed to augment the required power, and from 2 to
12 horse-power will then be required to actuate the machine; the light
will then be obtained in proportion to the power expended. Instead of
employing in the machine the helices G for magnetizing the electro-
magnets any required number of the helices F may be similarly employed
for that purpose. The helices F (Figures 1, 2, and 4), are all in series,
that is to say, the wires of each helix are so connected that the current
from each helix may pass in the same direction; the extremities are
united to the two binding screws T and T' (Figures 1, 2, and 6), from
which the current can be conducted by wires to any required point. The
machine shown in end elevation and section in Figures 1 and 2, as well
as the form of magnet, Figure 3, are drawn to a scale of th; all the
other Figures are drawn size. When currents are required of great
intensity, such as for the production of ozone, I substitute for the helices
F, F, Figures 1 and 2, and shown also at P, Q, (Figure 4), others
wherein a series of spirals or volutes of fine insulated wire are wound
directly upon the core, all the spirals of each helix and all the helices
being united in series and terminating at the two extremities in the
binding screws T, T¹. The total length of these spirals may vary from
7 to 12 miles according to the fineness of the wire employed for their
manufacture. When helices of this construction are employed I retain
the helices G or a certain number of the helices F for the purpose of
magnetizing the electro-magnets. The cores of these helices, as well as
the cores of those herein-after more particularly described, are formed of
bundles of fine iron wires secured at their extremities to two iron plates
smaller than those of the helices F', as shown at V (Figure 7), such plates
being simply split radially from the circumference to the centre and not

page_text: This
throughout. The spirals or volutes are enclosed in thick cases of
vulcanite or any other material of great electric resistance:
vulcanite disc is shewn at z (Figure 7).
I also construct helices in order to obtain great intensity on cores
formed of a bundle of wires, as herein-before described. I wind thereon
a thick insulated copper wire as a primary helice; I then pass a tube of
vulcanized india-rubber over this primary helice, and on this tube I wind
spirally or in a volute form a second helix of fine wire. The primary
helices are all united in series and pass through a commutator to proceed
to the magnetic helices in order to magnetize the magnets; the secondary
helices are also united in a single series. When helices constructed in
this manner are employed for the production of ozone a portion (nearly
one-half of each tooth of the commutator) is removed and replaced by
a piece of vulcanite or hardened india-rubber. The object of this is that
it is necessary in order to obtain a spark from the secondary helices that
there should be a perfect break or stop in the original current at each
change in the direction of the current, hence the necessity for large
divisions between the teeth of the commutator. At each passage of the
rubber from one tooth to another there will be an instant during which the
current will be broken, and at this instant the spark passes through the
secondary helices. When the helices of this construction are employed
in the machine the helices G (Figures 1 and 2) are not required. I fix
between the helices G (Figures 1 and 2) and the magnetic helices a
lever by means of which I am enabled to raise one of the rubbers m, m',
of the commutator and thus break the connection which exists between
the helices G and the magnetic helices, and at the same instant by
establishing a contact with a pin fixed for this purpose I am enabled to
discharge the whole current of the magnetic helices in any required
direction in order to effect explosions in mines for example, or for any
other similar purpose. Figure 5 shews the form of the cores of the
helices G; R is a back view and S is a side view thereof. Motion is
transmitted to the machine by the pullies Y, Y', from any convenient
prime mover.
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,-

page_text: First. The peculiar construction of magnets, substantially as herein-
before described and illustrated by Figures 1, 2, and 3 of my Drawings.
Second. The peculiar forms of the cores and end plates of helices,
substantially as here-before described and illustrated by my Drawings.
Third. The construction and use of helices formed with wholly or
partially split or divided cores.
Fourth. The introduction into electro-magnetic and magneto-electric
machines of helices of sufficient intensity to produce ozone without the
intervention of a Rhumkoff coil or coils of a similar combination, sub-
stantially as herein-before described.
Fifth. The peculiar construction and arrangement of commutator
whereby it is enabled to break the circuit of the primary helices, sub-
stantially as herein-before described.
Sixth. The application of a current changer in the course of the wires
proceeding from the magnetizing helices to the magnet helices for the
purpose of instantaneously discharging all the currents in the magnetic
helices in any given direction, substantially as herein-before described.
In witness whereof, I, the said Frederic Hale Holmes, have to
this my Specification set my hand and seal, the Twenty-third
day of December, One thousand eight hundred and sixty-
eight.
F. H. HOLMES. (L.S.)