IMPROVEMENTS IN DYNAMO AND MAGNETO-ELECTRIC MACHINES
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lanc, in the
County of Middlesex,. Patent Agent, for an Invention of "IMPROVEMENTS IN
DYNAMO AND MAGNETO-ELECTRIC MACHINES." A communication from abroad
by William Laing, of Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 20th July 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN DYNAMO AND MAGNETO-ELECTRIC
MACHINES." [A communication from abroad by William Laing, of Paris,
France.]
In the various systems of magneto electric machines collectors or commutators
are used to rectify or render the currents continuous or uniform in direction.
Being always attached to the machine these organs are entirely dependent upon its
working.
This Invention has for its object to render independent of the machine the means
which rectify or make the currents uniform in direction, whereby certain advan-
tages in working accrue.
It is generally admitted that alternate current machines are the best generators
for the electric light, and the attention of inventors has been especially directed to
this class of machines, and has resulted in the production of the Alliance, Holmes,
and De Meritens magneto electric machines, which work without commutators, and
require no attention; but the small amount of work produced by these machines
has caused attention to be directed to dynamo-electricity, the result being the
dynamo-electric machines of Lontin (1868 model), Wilde, Holmes, and others.
These macbines, which are furnished with commutators to render continuous one
portion of the current to excite the field magnets, were incapable of working any
great length of time in consequence of the heating and the rapid wear of the com-
mutator. To obviate this important defect Lontin devised a method which enabled
the commutators to be dispensed with, which method consisted in the employment

page_text: of two machines, the one producing a direct continuous current, and serving to
excite the other, which was thus rendered magneto electric. An electric generator
was thus produced having no commutators, and the result was deemed so satis-
factory that the new machines of Gramme, Siemens, Jablochkoff, and Dubois were
constructed on the same principle. This method of solving the difficulty involves
the employment of two machines, which would be unnecessary were the use of
commutators rendered practically available. To accomplish this is the object of the
present Invention. If a commutator works in water or in any other liquid of little
or no conducting power, the electric sparks are not produced, and the commutator
does not become heated. This method of employing a commutator furnishes an
apparatus producing alternate currents, and comprising but a single machine.
-
In carrying this Invention into effect I may adopt the following arrangement :-
In constructing the dynamo-electric machine the induced or armature magnets may
be made to revolve in front of the inducing or field electro magnets, or vice versa.
The whole or a part only of the current is collected by one or more pairs of contact
rings, and thus placed at the disposal of the operator. As it is necessary to rectify
or render uniform in direction at least a portion of the electric current produced to
magnetise the field or inducing magnets, the current is passed through a commu-
tator arranged in a box filled with water. This box may be arranged at any
convenient part of the machine, or may be quite apart therefrom. From the
commutator-the current passes to and excites the field magnets. The commutator
is driven from the machine shaft, or by any other suitable means.
If the machine is constructed with stationary armature magnets the contact rings
are dispensed with, only a single pair being required to convey the current to the
field magnets.
It is unnecessary to describe any particular kind of commutator, as the ordinary
forms may be used, or one resembling Masson's.
The commutator above described may also be applied to rectify the currents of
magneto electric machines. The advantages of this Invention are economy and
facility for regulation during working.
The Invention is applicable in all cases in which electricity is employed, whether
for producing light or in electro-chemistry, as either alternate or continuous currents
-may be obtained at will. By using a number of insulated commutators several
,independent continuous currents may be furnished.

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
20th January 1882.
rr
J
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. IMPROVEMENTS IN DYNAMO AND MAGNETO ELECTRIC
MACHINES." A communication from abroad by William Laing, of Paris;
France.
In the various known systems of magneto electric machines the alternate currents
produced are rectified or rendered uniform in direction by means of collectors or
commutators which, being always attached to the machine, are entirely dependent
upon its working. This Invention has for its object to render independent of
the machine the means of rectifying the currents or making them uniform in
direction, whereby certain advantages in working accrue.
It is generally admitted that alternate current machines are the best generators
for the electric light, and the attention of inventors has been especially directed to
this class of machines, and has resulted in the production of the Alliance, Holmes,
and De Meritens magneto electric machines, which work without commutators, and
require no attention; but the small amount of work produced by these machines
has caused attention to be directed to dynamo electricity, the result being the
dynamo electric machines of Lontin (1868 machine), Wilde, Holmes, and others.
These machines, which are furnished with commutators that rectify one portion of
the current for the purpose of exciting the field magnets, were incapable of working
any great length of time in consequence of the heating and the rapid wear of the
commutator. To obviate this important defect Lontin devised a method whereby
the commutators could be dispensed with, which method consisted in the employ-
ment of two machines, the one producing a direct continuous current, and serving
to excite the other. An electric generator was thus produced having no commu-
tators, and the result was deemed so satisfactory that the new machines of Gramme,
Siemens, Jablochkoff, and Dubois were constructed on the same principle. This
method of solving the difficulty involves the employment of two machines, which
would be unnecessary were the use of commutators rendered practically available.
To accomplish this is the object of the present Invention. If a commutator works
in water or in liquid of little or no conducting power, the electric sparks are not
produced, and the commutator does not become heated. By this method of
employing a commutator one is enabled to have an apparatus producing alternate
currents, and comprising but a single machine.
In carrying this Invention into effect I may adopt the following arrangement :-
In constructing the dynamo-electric machine the induced or armature magnets may
be made to revolve in front of the inducing or field electro magnets, or vice versa.
The whole or a part only of the current is collected by one or more pairs of collecting
rings, and thus placed at the disposal of the operator. As it is necessary to rectify
or render uniform in direction at least a portion of the electric current produced, in
order to magnetise the field or inducing electro magnets, the current is passed
through a commutator arranged in a box filled with water. This box may be
Jocated at any convenient part of the machine, or may be quite apart therefrom.
From the commutator the current passes to and excites the field magnets. The
commutator is driven from the machine shaft, or by any other suitable means.
If the machine is so constructed that the induced magnets are stationary, the
collecting rings are dispensed with, only a single pair being required to convey the
current to the field magnets.
It is unnecessary to describe any particular kind of commutator, as the ordinary
forms may be used; or it may be constructed like Masson's circuit breaker.

page_text: The commutator above described, whether distinct from the machine or mounted
upon it, may also be applied to rectify the currents of magneto electric machines.
The advantages of this Invention are economy and facility for regulation during
working. The Invention is applicable in all cases in which electricity is employed,
whether for producing light or for electro-chemical operations, as either alternate
or continuous currents may be obtained at will. By using a number of insulated
commutators several independent continuous currents may be furnished.
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
hereinbefore in part recited Letters Patent is,-
The employment in combination with a magneto or dynamo electric machine of
a commutator (including any collector or circuit breaker) working in water or
other fluid of little or no conductivity, for the purpose of rectifying the whole or
a part of the machine current, and dependent or independent of the machine
at will
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twentieth day of January, A.D. 1882.