IMPROVEMENTS IN DYNAMO-ELECTRIC AND MAGNETO-ELECTRIC MACHINES
Year: 1877

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-ELECTRIC AND MAGNETO-ELECTRIC MACHINES." A communication
from abroad by the Firm of Lontin and Company, of Paris, France.
Sealed the 28th May 1878, and dated the 24th December 1877.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 24th December 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN DYNAMO-ELECTRIC AND MAGNETO-ELECTRIC
MACHINES." [A communication from abroad by the Firm of Lontin and Company,
of Paris, France.]
In all existing dynamo-electric machines it is necessary in order to render the
currents uniform in direction to employ commutators or collectors, which require
frequent regulation, as, owing to the constant friction to which they are subjected,
they sooner or later become worn to such an extent that the currents no longer
pass properly.
The object of the present Invention is to produce currents, naturally uniform in
direction, without the use of collectors or commutators.
Dynamo-electric machines require to be variously modified in construction,
according to the work to be performed, and as the improved machine of this Inven-
tion is susceptible of the numerous modifications that may be required, it will be
sufficient here to describe its principle only.
If a magnet or electro-magnet be made to move parallel with a bar of iron upon
which are placed several small coils arranged as for induction, a current will be
produced in each coil, which, although of variable intensity in each coil will yet
have the same direction.
If the ends of the bar be brought together, so as to form a ring, the coils thus
placed will always produce a current of the same direction, during the passage

page_text: parallel thereto of a magnet or electro-magnet. As many magnets or electro-
magnets may be so arranged as the size of the ring will allow, and the magnetic
poles by which the ring is influenced should of course all be similar.
If one or more such rings, either dependent on or independent of each other, be
made to turn in front of a number of similar magnetic poles, each of the coils upon
the ring or rings will produce a current in one duection, so that by connecting the
poles of these small coils with friction rings upon the rotating shaft currents
naturally invariable in direction may be collected and employed, as in other
dynamo-electric machines, wholly or in part for exciting the primary electro-
magnets.
If instead of these permanent magnets be employed, the machine will be magneto-
electric, thus commutators, collectors, or other means of rendering the currents
uniform in direction are entirely dispensed with.
The ring may be of any suitable form, provided that it receives rotary motion;
for example, it may be a tube, a torus, or a polygon. The number of the primary
magnets is entirely optional.
The ring may also be composed of a series of coils, attached end to end in a
circular or polygonal form.
The entire independence of each of the coils and of their core will in certain
cases permit of a simpler construction; for example, a single coil may be made to
cover the entire ring.
The primary magnots may be placed either laterally on the inside or outside of
the ring, or made to enclose it more or less.
In practice it is advantageous to employ both poles of the magnets, and for this
purpose it is only necessary to use two rings, influenced by the opposito polos, all
those for each ring being similar
In order that the working of the machine may be thoroughly understood, it will
be of advantage to explain briefly the laws which govern its action,-
1st. When an induction coil approaches the pole of a magnet a current is
produced in the coil in the opposite direction to that of the inducer (a magnet being
considered as a solenoid according to Ampère's theory)
2nd. When the coil is removed from the polo a current in the inverse direction
to the former one is produced.
3rd. If the coil on being removed be completely reversed, so as to present its
opposite end to the pole, the current will be in the same direction as the former
one.
The above three laws may be supplemented by the three converse laws, without
however affecting the result
As an example of the practical application of these laws, forming the basis of the
present Invention, suppose a coil to be rotated between two similar magnetic poles,
the coil being tangential to its circle of rotation, and let the two ends of the coil be
distinguished by the letters x, y. When the end approaches one of the magnetic
poles an inverse current is produced in the coil, and when the coil recedes from the
said pole a direct current would be produced; but as the opposite end y of the coil
is now presented to the pole the current will still be inverse, as when approaching
the pole. The coil continuing to rotate presents its end to the other magnetic
pole (which is similar to the former one) and the same effect is reproduced, ie., an
inverse current is produced; and on the coil receding from the second pole the
current (which would be direct did the coil not present its opposite end to the
pole) is again inverse. Thus the circular motion of a coil between two similar
poles produces four currents, all in the same direction, and therein lies the funda-
mental principle of the Invention, which obviates the use of any commutators or
of collectors in dynamo-electric and magneto-electric machines.

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 14th June
1878.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent.
"IMPROVEMENTS IN DYNAMO-ELECTRIC AND MAGNETO-ELECTRIC
MACHINES "
A communication from abroad by the Firm of Lontin and Company,
of Paris, France.
In all existing dynamo-electric machines it is necessary in order to render the
currents uniform in direction to employ commutators or collectors, which require
frequent regulation, as, owing to the constant friction to which they are subjected,
they sooner or later become worn to such an extent that the currents no longer
pass properly.
The object of the present Invention is to produce currents, naturally uniform in
direction, and thereby to dispense with the use of collectors or commutators.
The theory of uniform currents induced by magnetization is not new, but no
attempt has been yet made to apply it practically to the production of dynamo.
electricity. What was therefore required was to find a combination of parts
applicable in the construction of dynamo-electric machines, susceptible of being
usefully employed for all the purposes for which electricity is available.
This new system of machine, like all the Lontin machines, may be arranged for
tension or quantity, according to requirements.
Dynamo-electric machines, requiring to be variously modified in construction,
according to the work to be performed, and the improved machine of this Inven-
tion being susceptible of the numerous modifications that may be required, it will
be sufficient here to describe its principle only.
If a permanent or an electro-magnet be made to move parallel to a bar of iron,
upon which are placed several small coils arranged as for induction, a current will
be produced in each coil, which, although of variable intensity in each coil will yet
have the same direction.
If the ends of the bar be brought together, so as to form a ring, the coils thus
placed will always produce a current of the same direction, during the passage,
parallel thereto, of a magnet or electro-magnet. This being established, it follows
that as many magnets or electro-magnets may be so arranged as the size of the
ring will allow, the magnetic poles by which the ring is influenced being of course
similar.
If now one or more such rings, either dependent on or independent of each other,
according to circumstances, be made to turn in front of a number of similar magnetic
poles, each of the coils upon the ring or rings will produce a current always in the
same direction, so that by connecting the poles of these small coils with friction
rings upon the rotating shaft currents naturally invariable in direction may be
collected and employed, as in other dynamo-electric machines, wholly or in part,
for exciting the primary electro-magnets.
If permanent instead of electro-magnets be employed for primary magnets, the
machine will be magneto-electric; thus commutators, collectors, or other means of
rendering the currents uniform in direction are entirely dispensed with.
The ring may be of any suitable form, provided that it can receive regular rotary
motion; for example, it may be a tube, a torus, or a polygon. The number of the
primary magnets is entirely optional.
The ring may also be composed of a series of coils, attached one after the other
in a circular or polygonal form.
The entire independence of each of the coils and of their core will in certain
cases permit of a simpler construction, for example, a single coil may be made to
cover the entire ring
The primary magnets may be placed either laterally inside or outside of the ring,
or be made to envelop the surface of the ring more or less.

page_text: As in practice it is advantageous to employ both poles of the magnets, it is only
necessary for this purpose to use two rings influenced by opposite poles, all those
for each ring being similar.
In order that the working of the machine may be thoroughly understood, it will
be of advantage to explain briefly the laws which govern its action,―
1st. When a coil approaches the pole of a magnet a current is induced in the coil
in the opposite direction to that of the magnet (a magnet being considered as a
solenoid according to Ampère's theory)
2nd When the coil is removed from the same pole, a current is induced in the
inverse direction to the former onc.
3rd. If the coil on being removed be completely turned end for end, so as to
present its opposite end to the pole, the current will be in the same direction as the
former one.
The above three laws may be supplemented by the three converse laws, without
however affecting the result.
As an example of the practical application of these laws, forming the basis of the
present Invention, suppose a coil to be rotated between two similar magnetic poles,
the coil being tangential to its circle of rotation, and let the two ends of the coil bo
distinguished by the letters x, y. When the end approaches one of the magnetic
poles an inverse current is induced in the coil, and when the coil recedes from the
said pole a direct current would be produced; but as the opposite ond y of the coil
is now presented to the pole the current will still be inverse, as when approaching
the pole. The coil continuing to rotate presents its end x to the other magnetic
pole (which is similar to the former one) and the same effect is produced, .e, an
inverse current is produced; and on the coil receding from the second pole the
current (which would be direct, did the coil not present its opposite end to the
pole), is again inverse. Thus the circular motion of a coil between two similar poles
produces four currents, all in the same direction, and therein lies the fundamental
principle of the Invention, which obviates the use of any commutators or collectors
in dynamo-electric and magneto-electric machines.
Having described the nature of the said Invention, and the manner of per-
forming the same, I declare that what I claim as the Invention to be protected by
the herein-before in part recited Letters Patent is, any dynamo or magneto electric
machine based on the principle herein specified, whereby currrents, naturally
invariable in direction are produced, thereby dispensing entirely with any means
for rendering them uniform in direction.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Thirteenth day of June, in the year of our Lord
One thousand eight hundred and seventy-eight.