IMPROVEMENTS IN DYNAMO AND MAGNETO ELECTRIC MACHINES
Year: 1875

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN DYNAMO AND MAGNETO ELECTRIC MACHINES."—A com-.
munication from abroad by Emile Bertin, of Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 11th December 1875.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN DYNAMO AND MAGNETO ELECTRIC
MACHINES," to be as follows:-
This Invention relates to improvements in dynamo. and magneto
electric machines; and it consists in placing upon the shaft of the
machine as many collectors or pairs of contact rings as there are
induction coils in the machine. Thus each commutator or contact ring

page_text: having its own special rubber a portion only of the machine current
may be used. All the units of the machine (coils or helices) may be
coupled either for tension or quantity, so that the machine may be
adapted to the purpose required, the grouping of the coils being variable.
The unit may in small machines be composed of simple units; take, for
example, a machine composed of 24 coils. If the machine be small I
compose the unit of, say, 2, 3, 4, or 6 coils, and I place upon the shaft,
say, 12, 8, 6, or 4 commutators or pairs of contact friction rings, and I
am thus enabled to group the coils in any manner desired. On the
other hand for a powerful machine each simple unit may have several
commutators or pairs of friction rings, for which purpose each simple
unit (induction coils) should be formed of several wires, thus enabling
a machine with twelve coils, for example, to have, say, 24, 36, or 48,
commutators or contact rings.
The unit may also be variable in the same machine and be composed
of simple variable units; for example, a machine of 28 coils may have
7 commutators or pairs of contact rings, the first of which receives the
current from a single coil, the second from two coils, the third from
three coils, and so on.
It will be readily seen how by the above means I am enabled to
obtain with the same machine any number of combinations both for
quantity or for tension.
I may also adapt both commutators and contact rings in the same
machine in order to produce alternate or continuous currents at will.
The following relates to an improved arrangement of dynamo-electric
machine whereby considerable results are obtainable :-I take a dynamo-
electric machine of any kind having a'continuous current and completely
close the circuit upon itself, but instead of interposing the work to be
done in a break made in the circuit I interpose it in a derived 'current
from the poles of the machine which furnish the current to the electro-
magnets. In this manner I obtain what I term a lateral derived
current, which considerably augments the power when employed in
electro-metallurgy for magnetizing light producing apparatus and other
purposes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 8th June 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of December, in the year
of our Lord One thousand eight hundred and seventy-five, in the thirty-
ninth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Alexander Melville Clark, Her special
license that I, the said Alexander Melville Clark, my executors, admini-
strators, and assigns, or such others as I, the said Alexander Melville
Clark, my executors, administrators, and 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 DYNAMO AND MAGNETO ELECTRIC MACHINES," a communi-
cation to me from abroad by Emile Bertin, of Paris, France, upon the
condition (amongst others) that I, the said Alexander Melville Clark,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, 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 imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Alexander Melville Clark, 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
Sheet of Drawings, and to the letters and figures marked thereon, that
is to say:

page_text: of contact rings; and in some cases the revolving shaft of such machines
has had a commutator or pair of contact rings placed on it on either
side. These arrangements present however certain disadvantages, and
the present Invention which is designed to obviate these objections
consists in placing upon the shaft of the machine as many collectors or
pairs of contact rings as there are induction coils in the machine. Thus
each commutator or contact ring having its own special rubber a portion
only of the machine current may be used if desired, and all the units of
the machine [(coils or helices) may be coupled either for tension or
quantity, so that the machine may be adapted to the purpose required,
the grouping of the coils being variable. The unit may be composed of
simple units; for instance, in a machine composed of 24 coils if the
machine be small I compose the unit of, say, 2, 3, 4, or 6 coils, and I
place upon the shaft, say, 12, 8, 6, or 4 commutators or pairs of contact
rings, and I am thus enabled to group the coils in any manner desired.
On the other hand for a powerful machine each simple unit might have
several commutators or pairs of friction rings, for which purpose each of
the simple units (induction coils) should be formed of several wires,
thus enabling a machine with twelve coils, for example, to have, say,
24, 36, or 48 commutators or contact rings.
The unit may be variable in the same machine, and be composed of
simple units also variable. For example, a machine of 28 coils may
have 7 commutators or pairs of contact rings, tlie first of which receives
the current from a single coil, the second from two coils, the third from
three coils, and so on.
It will be readily seen how with the above means I am enabled to
'obtain with the same machine any number of combinations both for
quantity or for tension.
I may also adapt both commutators and contact rings in the same
machine in order to produce alternate or continuous currents at will.
(I term alternate currents the currents produced by machines known by
the name of the "Alliance." .
The following relates to an arrangement of dynamo-electric machines
whereby considerably improved results are obtainable-I take a
dynamo-electric machine of any kind having a continuous current and
completely close the circuit upon itself, but instead of interposing the
work to be done in a break made in the circuit I interpose it in a derived

page_text: current taken from the poles of the machine which furnish the currents
to the electro-magnets. In this arrangement, which I term a lateral
derived current, if the work to be performed is constant as in electro-
metallurgy and other operations the result is very much improved.
4
"
The following is an example of the application of the principle of this
Invention Figures 1 and 2 of the accompanying Drawing represent
the improved dynamo-electric machine. A, A, are the inducing electro-
magnets; and B, B, the coils in which are produced the induction
currents to be utilized separately. For this purpose I dispose on the
machine shaft on either side the collectors or contact rings a, a, b, b,
as the case may be. The two ends of the wire of each of the coils B, B,
are attached, each of those on the right corresponding to one of the poles
to the two collectors 6, 6, and those on the left corresponding to the
opposite pole to collectors a, a, each collector thus having but one wire
connection. In this manner I am enabled by means of rubbers making
contact with the collectors to utilize separately the current produced in
each of the corresponding coils.
It is evident that several coils may be coupled with the same collector
when the current from a single coil is too weak to be utilized. I have
shown the arrangement as adapted to two inclined coils only, but it will
be understood that the other coils are similarly disposed. The number
of collectors would be in all cases proportionate to the power of the
machine and the number of currents it is desired to obtain. It will
also be evident that the currents may be combined two and two or
in other manner by connecting the studs on the rubbers by means of a
wire. The multiple collectors or contact rings are employed in the
same manner whatever may be the form of the inducing electro-
magnets or the arrangement of the induced part.
In applying the improvements to a machine on the Lontin system it
will be evident that it is only necessary to attach one by one to a
multiple collector disposed at each end of the shaft the two ends of the
wires of each coil or tooth of the wheel to obtain the same result.
Figure 3 shows a Lontin machine adapted for obtaining lateral
derived currents according to the 2nd part of the present Invention.
The ends b, b, of the wires of electro-magnets A, A, are connected
together, while the two other ends are separately attached to rubbers
disposed along the collector C, and this according to the situation of the

page_text: poles corresponding to the signs and -i, In this manner the circuit
of the machine is completely closed. The current may then be taken
from each of the rubbers without it being necessary to interrupt the
circuit: Thus, as indicated in Figure 3, each of the wires F + and F -
is attached to one of the rubbers corresponding to poles + and
-
Having described the nature of the said Invention, and the manner
of performing the same, I declare that what I claim as the Invention to
be protected by the herein-before in part recited Letters Patent is,--
1st. The employment of lateral derived currents obtained by all kinds
of dynamo electric machines having continuous currents for all purposes
in which a constant current is required, such as in electro-metallurgical
and other operations.
2nd. The employment of commutators or contact rings in any suitable
number connected with either simple or compound units of induction,
whereby any combination whether for quantity or for tension may be
obtained, or continuous or alternate currents as desired.
•
.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Seventh day of June,
in the year of our Lord One thousand eight hundred and seventy-
six.