IMPROVEMENTS IN MEANS OR APPARATUS FOR PRODUCING ELECTRIC CURRENTS
Year: 1881

page_text: LETTERS PATENT to Adam Millar, of Glasgow, in the County of Lanark,
North Britain, for an Invention of "IMPROVEMENTS IN MEANS OR APPARATUS
FOR PRODUCING ELECTRIC CURRENTS."
Void by reason of the Patentee having neglected to file a Specification in
pursuance of the conditions of the Letters Patent.)
PROVISIONAL SPECIFICATION left by the said Adam Millar at the Office of
the Commissioners of Patents on the 20th December 1881.
"
ADAM MILLAR of Glasgow in the County of Lanark North Britain
MENTS IN MEANS OR APPARATUS FOR PRODUCING ELECTRIC CURRENTS."
IMPROVE-
This Invention relates to improvements in apparatus for producing electric
currents.
My improvements in apparatus for producing electric currents consist in
arrangements for utilising the inductive action which a magnet has upon a
conductor forming part of a closed circuit and placed in one part of the magnetic
field of the magnet, whenever the magnetism of the magnet is made to vary in
intensity by the action in another part of the magnetic field, of an armature, or
another magnet, or of a conductor carrying a current or of any other body which
increases or diminishes the magnetism of the magnet.
The following examples show various arrangements by which the principle of
the Invention may be carried out.
First. Let a permanent steel magnet of horse shoe form have an insulated
copper wire coiled round the north pole limb of the magnet, and the ends of the
wire joined together so as to form a closed circuit and a second wire coiled round
the south pole forming a second closed circuit. If an armature of soft iron be
brought into contact with the poles of the magnet, the magnetism of the magnet
will be rendered non-active or passive, and currents of electricity of momentary
duration will be produced in each of the two closed circuits that surround the
[Price 9d1

page_text: limbs of the magnet. If the armature be then withdrawn from contact with the
poles, currents will also be produced in each of the two closed circuits, but the
direction of the currents will be in a contrary direction to those first produced.
This arrangement is suitable in cases where it is desirable to have a maximum
of quantity along with a maximum of intensity. The quantity being the result of
the great difference in the intensity of the magnetism of the magnet before and
after the armature has been brought into contact with the poles; and the intensity
being the result of the very short space of time in which the change is made.
Second. Let a permanent horse shoe magnet with a closed circuit surrounding
each limb, as in the first example, have an armature of a horse shoe form, each
limb surrounded by a coil forming a closed circuits of insulated copper wire, and
made to rotate in front of the poles of the magnet, so that the two ends of the
limbs of the armature shall pass in close proximity to the two poles of the magnets
currents of electricity of momentary duration will be produced in the closed
circuits of the armature, and at the same time currents of electricity will be
produced in the closed circuits surrounding the limbs of the magnet.
These two sets of currents may be used (by means of suitable commutators)
either separately, or in combination with each other.
Third. In place of permanent steel magnets as in the first and second examples
electro-magnets may be used, the coil of wire for obtaining the momentary induced
currents being placed outside of the coil which carries the current from the
_battery_or_other-source-of-electricity and maintains the magnetism of the electro
magnets.
Fourth. In the preceding examples the magnets have been assumed to be
stationary and the variations in the magnetism to be caused by the movement of
armatures but the same inductive actions take place when the magnet is made to
move and the armature is fixed. The same inductive actions will be produced if
both armatures and magnets move in directions contrary to each other and also if
they both move in the same direction, but at different rates of speed.
Fifth. In the preceding examples all armatures have been described as the
ordinary soft iron armatures, but similar inductive actions will be produced if a
magnet be used in the place of a soft iron armature.
Electro-magnets may also be employed in place of soft iron armatures and
conductors carrying currents may be used likewise.
Sixth. In all the preceding examples the variations of the magnetism of the
magnets have been produced by the movement of the armature, or of the magnet,
or of both together, but the same inductive actions may be produced by a stationary
magnet and certain equivalents of an armature also stationary, such as an electro-
magnet, in which the current is made to increase or diminish, and so becoming
weaker or stronger in its action upon the magnet.
I am aware that the principle on which my Invention depends is employed as
one part of the apparatus or instrument known as the telephone, but the currents
of electricity produced in that application are of an extraordinary degree of
feebleness and quite inapplicable to the usual applications of electricity. Now by
my Invention currents may be produced of such a character as are suitable for the
production of light, heat, motive power, chemical decomposition, and the working
of telegraphic instruments.