IMPROVEMENTS IN THE METHOD OF AND IN MACHINES FOR PRODUCING ELECTRIC CURRENTS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents on the 27th December 1883. Commu-
nicated to him from abroad by Henry Monroe Paine, of Newark in the County
of Essex and State of New Jersey United States of America, Electrician.
ALEXANDER MELVILLE CLARK, of the firm of A. M. and W. Clark, of 53 Chancery
Lane in the County of Middlesex, Fellow of the Institute of Patent Agents,
IMPROVEMENTS IN THE METHOD OF AND IN MACHINES FOR PRODUCING ELECTRIC
CURRENTS" [communicated to him from abroad by Henry Monroe Paine, of Newark
in the County of Essex and State of New Jersey United States of America,
Electrician]
The object of this Invention is the construction of a magneto electric machine
possessing the dual property of accumulating electrical energy and discharging the
same under conditions of impact.
The usual and common action of magneto electric machines produces continuous
disturbance or flow of electric energy during the passage of the armature through
the magnetic field, and consequently when working under a closed circuit a
constant force equal to the duty to be performed is required to maintain its motion.
It has been found however by experiments that a series of impacts in a given time
develope greater results than that of a continuous disturbance for the same period
under like conditions of applied force.
When the armatures or helices of a magneto-electric apparatus, approach or
recede from the centre of the magnetic field, an electric current is induced in the
wire surrounding them, and in the ordinary dynamo apparatus this induced current
is constantly conveyed by the commutator to its point of duty.
In the apparatus of this Invention this induced current becomes stored in the
coils during their traverse of the maguetic field, and is released only, when the axis
of the armature and the neutral centre of the magnetic field are coincident, and as
the armature is in motion under the conditions of an open circuit, till the incidence
of neutral centre and axis occurs, it follows, that the force required to rotate the
armature is only one sufficient to overcome the inertia of the armature and its
accompanying details, together with the friction of its bearings, a condition of
things the reverse of magneto-electric action heretofore known,

page_text: The invention consists essentially first in a dynamo-electric machine, the
combination of stationary field magnets, revolving armatures and a commutator
mechanism combined therewith in such a manner, that when the armatures are
passing through the field of force during open circuit, they are charged with static
electricity, and when the neutral axes of the field magnets and armatures are
coincident or about so, the circuit is closed and dynamic electricity is discharged
through the commutator in the form of pulsating currents.
Second, In the method of producing pulsating electric currents consisting in
storing up static electricity, in a dynamo-electric machine during open circuit, and
discharging dynamic electricity through a commutator at or about the period when
the neutral axis of the field magnets and armatures are coincident, and the circuit
is closed.
In order to illustrate the structure of my invention, I will proceed to describe an
apparatus which comprises generally the result of experiments made during the
last thirty years.
The machine frame consists of two end frames of fine grey iron each having cast
on one side of its periphery cores in sections with intervening spaces, and on its
centre a hub. These plates are tied together. There is also an intermediate frame
of fine grey iron, having cast on both sides of its periphery cores equal in all their
dimensions and spacings with the cores on the end frames, and the centre of this
frame is supplemented with a hub.
A shaft traverses the centreings of the several frames, the centre one being
secured to the shaft and the hubs of the end frames acting as bearings therefor.
The faces of the cores on end frames must be true with the axis of the shaft,
and the faces of the central frame cores, together with their inner and outer
circumference, and also the body of the frame itself must be turned true with the
axis of the shaft in order that the central frame may rotate freely between the end
ones, with just spacings enough between their several cores to prevent contact, and
without shake or end motion.
One end of the shaft should be bored out to near the hub of the middle frame,
and a mortise made to connect with the bore.
The projections on the end frames are cores of the field magnets, and the
projections on the middle frame, are the armature cores.
The current wheel should be cast of fine copper, and consists of two plates one
secured to the shaft and the other separated by a non-conducting disc from the
first plate. Each plate carries on its periphery projections equal in number with
the cores on the end frames; these projections engage the spacings between their
opposite plate under conditions that maintain a space equal to one sixth of their
face measurement between or around their engagements. Copper discs rotate in
contact with the periphery of the current wheel at opposite sides thereof. Each
turns on an axis through mortised limbs jointed to a horizontal beam. The one
limb must be as much shorter than the other limb, as the width of the projections
on the current wheel.
The beam is centred on a stud that is screwed into one end frame, an insulated
block being interposed between its hub and the frame
The commutator consists of this beam the two limbs jointed thereto and the
copper discs which are kept in close contact with the current wheel by a spiral
spring. The one limb is insulated from the beam. The current spacings of the
current wheel should coincide with the grouping of the field magnets and the
intermediate insulated spacings should never exceed one-sixth in measurement
the current spacings. The axis of the one contact disc is in line with that of the
current wheel, but that of the other disc when the beam is horizontal is below the
axial line of the current wheel so that when the one disc is in contact with an
insulated space the other disc should engage a current space about one third of its
width. The arrangement of the cores of the field-magnet and the mode of winding
the wire upon them is such that the current in moving from one terminal around
the several cores to the other terminal must acquire an accelerated intensity equal

page_text: to the number of cores traversed, the action in fact hearing a strong analogy to
that of the combined elements of the galvanic order, the quantity being determined.
by the area and length of wire on one core, and the intensity by the number of
cores in circuit. The cores should be always of even number in order that they
may be grouped in polar couplets, the example here described having six of these
groups composed of twelve cores and we have the quantity of one couplet anl the
intensity of six. The two sets of field magnets are bro ight into one series by
insulated rods connecting corresponding terminals of which one is connected with
the limb which carries one of the contact wheels.
The armature cores are wound and grouped in similar couplets to those of the
field magnets, one end of each series being secured to the frame and their terminals
pass down to the shaft, the two series making a common circuit and terminating
in an insulated rod within the hollow of the shaft and to which the front plate of
the current wheel is attached. The currents generated are compelled to traverse
the coils around the magnet cores under condition of mutual acceleration and the
quantity condition will be as the number grouped and the intensity as the number
of groups. If for instance we start from one terminal and continue through to the
other, then we will have the quantity of one and intensity of twelve, the number
of cores, but if we divide the coils into two groups of six each, then we have the
quantity of two and intensity of six and so on until we reverse it and have the
quantity of twelve and intensity of one.
This description of the armature magnets is applicable to the field magnets with
the exception that I have obtained better results when the field magnets were
grouped for high intensity and those of the armature for a lower grade. The
construction of the current wheel does not differ in itself materially from the usual
current wheels of magneto electric machines, but the peculiar arrangements of the
rotating discs making contact with it, give entirely different results. Were the axis
of the two contact discs and the current wheel to be coincident, then the electric
currents generated by the motion of the armature would flow continuously from
their source to their duty and a continuous resistance be the result, but by
arranging one disc below (or above) the axial line as herein set forth, the generated
currents are working in an open circuit within or upon themselves, because the
arrangements of the discs are such that both discs are for a certain period on the
same plate (front or back) of the current wheel, and while this condition of things
exists the electric energy is accumulating without sensible resistance to the force
applied to rotate the armature, but there are periods when the discs for an instant
of time engage the separate plates and then the accumulated energy discharges or
passes off to its duty. Now at the moment of discharge there will be the same
resistance to the applied force by the act of discharge that is met with in any and
every other magneto-electric machine, but if the current wheel is so adjusted on the
shaft with relation to the neutral axes of the cores of field magnets and armature
magnets that when the different magnets neutral axes are coincident, the two discs
engage the separate plates, then the discharge will occur without any resistance to
the applied force for the reason that all resistant properties of the machine are at
that moment in equilibrium. The exact position of the discs with reference to the
current wheel, when the best results are obtained, is ascertained by adjusting the
same while the machine is in motion, care being taken that the range be not too
great, in which instance deflagration of the current spacings will occur.
I have, in giving this description of this Invention, confined myself to its
structure when specially designed for decomposing fluid bodies. Experiments now
covering 30 years have determined the fact that impulse or impact of the electric
energy is an essential element in disintegrating or otherwise resolving fluid bodies,
or bodies possessing in themselves the property of diffusing the electric currents.
Therefore the apparatus thus described is not designed for purposes of light when
the voltaic arc or incandescent lamp are concerned. When the machine is designed
for the latter purpose, the axes of both discs should be in line with the axis of the
current wheel and the insulating spaces around its periphery be adjusted so that

page_text: the discs will simultaneously engage the insulating space at the moment that the
neutral axes of the cores of the field and armature magnets are coincident. The
grouping for intensity or quantity may be the same as when the machine is
designed for decomposing purposes.
A critical examination of the commutator discs adjusted as just described will
show that the discs engage at all times the different current spaces and that their
action results like the usual commutator in a constant flow of the electric current.