IMPROVEMENTS IN DYNAMO AND MAGNETO-ELECTRIC MACHINES
Year: 1880

page_text: LETTERS PATENT to Arthur William Lovell Reddie, of 66, Chancery Lane, in
the County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS
IN DYNAMO AND MAGNETO-ELECTRIC MACHINES." A communication from
abroad by Messieurs A. Biloret and C. Mora, of Paris, in the Republic of
France.
PROVISIONAL SPECIFICATION left by the said Arthur William Lovell
Reddie at the Office of the Commissioners of Patents on the 5th October
1880.
ARTHUR WILLIAM LOVELL REDDIE, of 66, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN DYNAMO AND MAGNETO ELECTRIC
MACHINES." [A communication from abroad by Messieurs A. Biloret and C. Mora,
of Paris, in the Republic of France.]
The objects of the present Invention are, first, to divide the currents of dynamo
electric machines, so as to obtain two or more circuits in one machine; and,
secondly, to obtain greater strength and efficiency in the armatures of dynamo and
magneto electric machines.
In dynamo electric macbines as usually constructed, the current of electricity
induced in the rotating armature is passed around all the poles of the field magnets
in succession. This construction of machine under ordinary conditions provides only
for a single circuit, and will operate but a single regulator or lamp.
According to the present Invention the wires which surround the field magnets
of any type of machine are connected at one end in a group to one of the brushes
of the commutator, the other ends being connected with separate circuits and led
back to the other commutator brush. By this means as many lamps may be main-
tained as there are magnetic poles in the machine. Thus in machines of the Gramme
or Siemens type, which have four poles, there would be four circuits, which in
machinery of the Lontin type, which have two poles only, there would be but two
circuits.

page_text: The second part of the Invention relates to an improved form of armature,
whereby greater strength of construction and increased efficiency are obtained.
Heretofore armatures have been formed by placing the induction coils upon bobbins
which are arranged around a disc or core of wood or brass, and they have also been
constructed by securing the bobbins by one end to an iron disc.
According to this Invention the bobbins forming the armature are placed between
two discs of iron and connected thereto by their ends. By this mode of construction
not only is greater strength and solidity secured, but the magnetisation of the
arinature cores is more complete, and a less speed of rotation is requisite to
obtain the induced current desired.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Arthur William Lovell Reddie in the Great Seal Patent Office on
the 5th April 1881.
ARTHUR WILLIAM LOVELL REDDIE, of 66, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN DYNAMO AND MAGNETO ELECTRIC
MACHINES." A communication from abroad by Messieurs A. Biloret and C. Mora,
of Paris, in the Republic of France.
The object of the present Invention does not apply alone to one class of machines,
but is applicable to the greater number of magneto or dynamo electric machines.
In considering, for example, the application of this Invention to three types of
machines, if we take the "Gramme," the "Lontin," or the "Siemens" machine
having direct currents, a single lamp only can, under ordinary conditions, be
operated by one machine, but by the present Invention the induced current is
passed round all the poles of the field magnets at once, and a current from each
pole where the wire of that pole comes out can be utilized. The result of this
arrangement is that there will be four distinct currents with the Gramme or
Siemens machines, which have four poles, and two currents with the Lontin
machine, which has but two poles.
This number of currents can be multiplied indefinitely, inasmuch as many wires
of various lengths or gauge can be wound on each pole of the field magnets according
to the "tension or quantity" required, which thus permits as many currents of the
same or of different value as may be required to be obtained with a single direct
current machine.
The second part of this Invention relates to an improvement by which greater
solidity is imparted to the armatures of dynamo or magneto electric machines,
electricity is induced with more facility, and reverse currents are much diminished.
In many machines, such, for instance, as those of the Alliance Company, Breguet,
Holmes, Wallace-Farmer, Wilde, and others, the induction bobbins are assembled
round a disc or cylinder of wood or brass, or are held fast by one end to a disc of iron.
This mode of mounting not being very strong it is now proposed to mount the
bobbins between two cheeks of iron.
The advantages of this mode of construction are that it is strong and cheap and
can be easily repaired in any part, whilst the magnetisation of the cores of the
bobbins being more complete the machine may be run at a lower speed than has
been necessary hitherto.
In order to more fully explain the nature of these improvements, a Drawing is
annexed of a dynamo-electric machine, constructed according to this Invention.
Fig. 1 represents a front view partly in section of a dynamo electric machine;
Fig. 2 is a plan view of the same, also partly in section.
b, b, are the induction bobbins, the cores of which are mounted between the two
cheeks or rings of iron J, J', thus forming tie pieces which give great strength to
the armature D, which armature is keyed to the axle A of the machine.
B, B', B, B³, are four bobbins constituting the field magnets, which are magnetised
by means of the commutator C also keyed upon the axle A. The inner ends of the
wires coiled around these bobbins are grouped together at X, the outer ends being
severally connected to the binding screws 1, 2, 3, 4, fixed on insulated copper blocks.
These copper blocks can be coupled together in pairs or otherwise by means of
copper plugs y, of which only one is shewn in the Drawing as coupling the binding
crews 2 and 3. Thus the current will pass through two of the field magnets, and
stronger current is obtained than can be obtained from the binding screws 1 and 4,
ach current in this latter case passing through one field magnet only.

page_text: Many currents of different degrees of intensity can thus be obtained from a
single commutator by varying the number and position of the copper plugs.
This kind of machine can be employed in all cases where electricity is required,
either as an electric generator or as an electro-motor.
Instead of using one commutator and collecting from it several currents, several
commutators may be used in the same manner as is above indicated.
The collecting brushes shewn in the Drawing as bearing upon the commutator C
may be advantageously replaced by the rotary metallic wire brushes shewn in
Figures 3 and 4, which will not only cause less friction, but will offer a much larger
wearing surface than brushes of the form ordinarily employed.
Having now set forth the nature of the said Invention of "Improvements in
Dynamo and Magneto Electric Machines," as communicated to me by my foreign
correspondents, and explained the manner of carrying the same into effect, I wish
it to be understood that under the above in part recited Letters Patent I claim,-
First. The construction and arrangement of an electric generator, substantially
as herein shewn and described, whereby many currents of different degrees of
intensity can be obtained from a single commutator or commutators.
Secondly. In an electric generator, constructing the rotating armature with two
cheeks of iron, substantially as and for the purpose herein shewn and described.
In witness whereof, I, the said Arthur William Lovell Reddie, have hereunto
set my hand and seal, this Second day of April, in the year of our Lord
One thousand eight hundred and eighty one.
ARTHUR W. L. REDDIE. (L.S.)