IMPROVEMENTS IN MAGNETO-ELECTRIC AND DYNAMO-ELECTRIC MACHINES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents on the 16th March 1880. A communication
from abroad by Auguste de Méritens, of Paris, in the Republic of France.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. " IMPROVEMENTS IN MAGNETO-ELECTRIC AND DYNAMO-ELECTRIC
MACHINES." A communication from abroad by Auguste de Méritens, of Paris, in
the Republic of France.
This Invention relates to magneto electric and dynamo-electric machines with
alternate currents, and it consists in enabling these machines to furnish an alternate
current without the employment of an exciting machine for producing a continuous
current for magnetizing the inductors. According to this Invention the latter are
magnetized by the alternate current itself without the necessity for changing its
direction by means of a commutator or collector.
In order that the nature of the Invention may be understood I shall describe, as
an example, its application to the magneto-electric machine known as De Méritens'.
In machines of this construction all the coils of the ring are wound in such a
manner that the exit wire from one coil is soldered to the exit wire of the next coil,
and the extremity of the entering wire of one coil is soldered to the entering wire
of the next coil. Hence it results that there are two entering wires or two exit
wires leading to the binding screws where the current from the machine is
collected. It also results that all the coils of the ring are traversed by one current,
which changes its direction during each revolution as many times as there are coils
in the ring.
Taking one of the coils as an example of the operation of the whole, each time
that the coil passes before the north pole the said coil is traversed by a current of
induction, which preserves the same direction during the whole time that the core
is passing the north. pole. When the first end of the core arrives opposite the
south pole the coil will be traversed by a current of induction in the opposite
direction to that by which it was traversed when passing the north pole, and this
current will preserve the same direction (opposite to the induced current produced
by the north pole) during the whole time that the core is passing the south pole.
Consequently each time that one extremity of a coil arrives opposite a fresh pole
the direction of the current by which it is traversed becomes reversed. The same
effect is produced in all magnets or dynamo electric machines working with
alternate currents.

page_text: The result of this action is that two currents of opposite denominations are
obtained in succession, the direction of the current being reversed each time that
the coil changes its pole.
It is well known moreover that when one only of the two coils of a horse shoe
electro magnet is traversed by a current the electro magnet is affected by this
current, and that its two poles are almost of the same power as when both the coils
in lieu of one only are traversed by the current.
Now let it be assumed that in a magneto-electric machine, constructed upon
the system known as De Méritens', the two legs of each permanent magnet are
provided with a coil composed of an insulated conducting wire. The two coils of
the magnet are wound in the same manner as when they constitute an ordinary
electro magnet with its two poles, excepting that the coils are provided with separate
entering and exit wires and are independent of each other. In order that the two
poles may be of opposite denominations it is necessary for the current to enter and
leave at opposite ends in the two respective coils. The entering wire of one coil is
in metallic connection with one of the rubbers of the machine, and the entering
wire of the other coil is similarly connected with the other rubber of the same
machine. The other extremities of the wires of the coils are connected to binding
screws by which the current from the machine is collected, and are also in metallic
connection with two cylinders next hereinafter described.
These cylinders are constructed of metal, and are made of the same diameter as
the collectors of the machine which work against the rubbers. The periphery of
the cylinders is divided longitudinally into as many divisions as there are coils on
the ring of the machine; these divisions are formed by a series of alternate recesses
and projections on the periphery of the cylinder, so that there is a series of pro-
jections corresponding to one half of the number of coils, and a series of recesses
corresponding to the other half. The recesses are filled up with insulating material,
Buch, for example, as wood, glass, ebonite, and the like, and the cylinder is turned
so as to present a smooth cylindrical surface.
The two cylinders are similar and are keyed upon the shaft of the machine, being
provided with a central socket of hard wood or ebonite for the purpose of insulating
them from the said shaft. The said cylinders, which are so arranged that the
alternate insulated parts on the periphery of the one correspond exactly with the
metallic parts on the periphery of the other, are in metallic connection with the
collectors working against the rubbers.
Two rubbers similar to the rubbers before referred to are pressed by the action
of a spring against the cylinders. The rubbers secondly mentioned are respectively
metallically connected with one extremity of the wire of one coil, and with the
opposite extremity of the wire of the other coil, which are also connected with
the binding screws by means of which the current from the machine is collected.
The machine operates in the following manner, vist. :—
It is well known that each time a fresh coil passes before a pole the current
changes its denomination. Let it be assumed that one of the rubbers secondly
mentioned is upon an insulated part of the one cylinder when the current is passing
in a given direction, the other of the two rubbers secondly mentioned will then be
upon a metal or insulated part of the other cylinder. The current will traverse all
the convolutions of the one coil in order to pass to a lamp, for example, and as the
entering wire and the exit wire of the other coil are connected together at the last
mentioned cylinder, and the corresponding collector which are in metallic connection
with each other, the convolutions of this coil will not be traversed by this current.
The poles of the magnet will nevertheless be powerful poles of contrary denomi
When the
nations, and the machine will be working with a magnet with one coil.
one of the said two rubbers passes from an insulated part of the one cylinder to a
inetallic part of the same cylinder, the other rubber passes from a metallic part of
the other cylinder to an insulated part of this cylinder. At the same time the
denomination of the current changes and the current passes in the opposite
direction. The current then passes along the convolutions of the other coil, thus

page_text: following the direction necessary in order to cause both the poles to remain of the
same denomination as before. The machine will still be working with a magnet with
a single coil, but the actuating coil is situate on a different leg or branch of the
magnet.
What has been described with reference to one of the magnets is evidently
applicable to all the other magnets in the machine; a machine is thus produced
giving an alternate current and magnetizing its own inductors automatically
without altering the current and without the possibility of a spark. One circuit
is formed with all the coils on the south poles and another circuit is formed with
all the coils on the north poles. The current from all the coils of a ring may be
taken and employed for the magnetization before being allowed to pass to the lamp
if required, or the current from a few of the coils only may be employed for this
purpose. In the latter case two or more circuits will be available for the
burners.
According to another arrangement two coils are arranged on each of the legs of
the magnets, and the current of one denomination is then caused to pass in the coil
of one leg and in the coil of the other leg opposite to the other coil of the first
mentioned leg, and the current of the opposite denomination is caused to pass in
the other coils by connecting the wires in such a. manner that each pole always
remains of the same denomination, whilst the two poles are of opposite
denominations relatively to one another.
The De Méritens' magneto-electric machine has been selected for the purpose of
illustrating the application of the Invention, but the same system is capable of
being applied to the machines known as the Alliance, Holmes, and other machines.
By this means these machines are enabled to work with electro-magnets which are
substituted for the permanent magnets heretofore employed.
A new system of magneto-electric machine is thus produced, which may if
preferred act simply as a dynamo electric machine.
The force employed exclusively for the magnetization of the inductors is
converted into a current employed in the production of the light absolutely in
the same manner as the current of a Gramme machine supplying a regulator.
The same machine may be employed as required with a regulator, or with
Jablochkoff, Jamin, or other candles.