AN IMPROVED DYNAMO-ELECTRIC MACHINE FOR PRODUCING ELECTRIC CURRENTS
Year: 1878

page_text: LETTERS PATENT to Isac Louis Pulvermacher, of 194, Regent Street, in the
County of Middlesex, Electrician, for the Invention of "AN IMPROVED
DYNAMO-ELECTRIC MACHINE FOR PRODUCING ELECTRIC CURRENTS."
PROVISIONAL SPECIFICATION left by the said Isac Louis Pulvermacher at
the Office of the Commissioners of Patents on the 28th November 1878.
<
ISAC LOUIS PULVERMACHER, of 194, Regent Street, in the County of Middlesex,
Electrician. AN IMPROVED DYNAMO-ELECTRIC MACHINE FOR PRODUCING ELECTRIC
CURRENTS."
I form grooved cylinders or rings of soft iron capable of revolving one in the
other concentrically, one set of rings being fixed and the other movable, so that
the projections forming the groove should pass very close to each other without
producing injurious friction. In the grooves are lodged isolated conducting wires
either by winding them in a zigzag manner, or I surround the ring with the
isolated conducting wires in a coil like manner, so that the. wires are thereby
always lodged in the grooves and are flush with the projections. I wind the wires
according to the first case when currents of alternate directions are intended
to be produced; in the second, when the current is intended to be continuous.
Instead of winding wires by bending them for lodgment in the grooves I apply
also isolated conducting rods of the length of the cylinder and connect their ends
by small plates, each with two holes, which are mounted on the ends of the
conducting rods in accordance with the direction the current has to flow. These
rotatory rings I bring under the influence of either permanent, temporary, or
residuary magnetism while rotating, and thus produce currents of electricity pro-
portionate to the mechanical power used, and in a direction in accordance with the
Dmine G21

page_text: movement of the movable cylinder or set of cylinders, one set of poles or projections
on one ring or cylinder acting opposite to the other set of poles or projections on
the opposite ring or cylinder which surrounds the above.
The soft iron cylinders may be malleable, cast, or composed by compiling notched
rings made of iron plate tinned or not, and fastened together either between end
plates, or by soldering, so that the notches represent the grooves before mentioned.
If these kinds of rings are to receive the induction influence of permanent
magnetism for the production of continuous currents I place strong permanent or
temporary magnets inside as well as outside of one of this kind of revolving rings,
the poles of the magnets being so placed as to act on the wires as well as on the
soft iron rings in close proximity in such a manner that no neutralization of
induced currents can take place and the maximum of inductive power be
realized.
The conducting wires are suitably connected and their ends set in communication
with the electrodes for establishing the circuit; the mechanical movement of the
rings will thereby produce the intended work to be done by the electrodes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Isac Louis Pulvermacher in the Great Seal Patent Office on the 28th
May 1879.
ISAC LOUIS PULVERMACHER, of 194, Regent Street, in the County of Middlesex,
Electrician. "AN IMPROVED DYNAMO-ELECTRIC MACHINE FOR PRODUCING ELECTRIC
CURRENTS."
Hitherto the multiplication of induced currents from a permanent or a temporary
magnet has been obtained by an insulated conducting wire wound spirally and in
successive layers around a core which could be magnetized, from which it resulted
that only the spirals of conducting wire or the layer of spirals wound next or
nearest to the magnetised core were in immediate proximity with the said
imagnetised core, the whole forming an electro-magnet. The consequence of this
plan was that the inductive force of the other layers of the conducting wire was
considerably weakened by reason of the large extent of surface of the number
of superposed layers of wire and the distance separating such wires from
the temporary magnetic core, thus increasing the length of the conducting wire
and consequently its resistance without proportionately increasing its inductive
force.
Now I have found by practical experience that to increase or multiply the
inductive force requires likewise an increase in the number of magnets whose
surfaces should be brought very close to a large part of the conducting wire along
its whole length.
The advantages therefore of a multi-polar dynamo-electric machine constructed
according to the principles I have just set forth becomes evident when one considers
the large amount of resistance which can be eliminated from the conducting wire,
and how much the coercive force of the temporary magnet may be diminished.
My dynamo-electric machine constructed according to the foregoing principles is
represented in several views in the annexed Drawings. Figure 1 shows a longi-
tudinal section; Figure 2, an exterior end view; and Figure 3, an exterior view of
the opposite end. It is principally composed of two cylinders placed concentrically
one in the other, the outer cylinder a is fixed, and the inner cylinder b is movable
with the axis c by which its carried, the latter being rapidly revolved by a pulley d
or other means set in motion by any description of motor.
The axis c turns in supports f, f', provided with adjustable split bushes or
bearings e formed of several parts which may be tightened up by the regulating
screws g, the object being to obtain a perfect centreing for the cylinders a, b, one in
the other, these cylinders being allowed only just sufficient play between each other
that they do not touch.
The two cylinders a, b, constituting the principal parts of my machine are
constructed in the following manner :-
The fixed cylinder a is formed by placing a number of soft iron rings or discs h
together side by side. A face view of one of these rings is shown in Figure 4, being
represented twice the size of the preceding Figures for the purpose of showing how
these rings or discs are cut or formed and for what purpose.
These rings or discs h present a certain number of teeth i and also a certain
number of holes j corresponding to as many iron rods or bolts k, these bolts
passing through the holes of a certain number of rings, the latter being separated from
each other by means of a number of small washers also traversed by the bolts k,
thus constituting an open sided cylinder which is kept rigid and adherent by
means of the said bolts k on a fixed wooden support forming, so to speak, the
bottom of the cylinder a. The other end of this cylinder is supported and kept
fixed by a wooden annular support m.

page_text: It is to be understood that all the teeth i of the discs or rings h next to each
other are in the same line, that is to say, they form a series of longitudinal grooves
in the interior of the cylinder a. These grooves are intended to receive an insulated
copper conducting wire o of sufficient thickness to fill up the said grooves, the wire
being laid in them one by one in zig-zag form one end to the other alternately and
in all the grooves on the interior surface of the cylinder. The two ends of this
wire o are fastened to two little terminals p, p, fixed on the wooden support land
shown in detail view Figure 5, to which reference is made hereafter when indicating
the course of the electric current.
The movable cylinder b is formed like the preceding, of rings or discs r, a face
view of one of these rings being shown in Figure 4 in a position concentric to the
two cylinders. These discs or rings are also separated or kept apart by washers s
and have bolts t passed through them, the bolts also passing through the bottoms
or ends u, u¹, of wood or other insulating material fixed against shoulder plates c¹,
forming part of the axis c.
It will be seen by reference to Figure 4 that the teeth v of the rings r are on the
outer edge or circumference of the cylinder b, so that during the action of the
machine these teeth pass rapidly in front of those on the cylinder a.
The teeth of the rings being in a line with each other form longitudinal
grooves on the outer circumference of the cylinder b. These grooves are likewise
intended to receive a conducting wire x similar to the before mentioned wire o, the
wire being laid in the grooves one by one from one end to the other alternately in
a zig-zag manner progressively in all the grooves of the cylinder.
The two ends of this wire x are brought outside and fastened to two metal rings
or wheels y, y¹, mounted and insulated from each other by an insulating medium z
affixed to and turning with the axis c of the movable cylinder b.
In Figure 5 may be seen the position of the terminals p, p, to which the ends of
the conducting eo from the cylinder a are attached; the rings or wheels y, y',
to which the ds of the conducting wire x from the movable cylinder b are
fastened, may also be seen in this Figure. 1 and 2 are metallic brushes fixed in the
terminals p, p, each brush resting in the groove or channell of one of the wheels
or rings y, y, serving as conductible connections and allowing free passage to the
current through the whole length of the wires o and x, passing from thence to the
electrodes.
I may place the conducting wires o and x in various ways, thus, for example,
instead of placing them in the grooves of the cylinders in zig-zag manner I may
wind them in longitudinal spirals around the body of the cylinder and laid in the
grooves from one end to the other, passing from one tooth to the neighbouring
one.
In the first case, that is to say, with the wires in zig-zag form, I produce currents
in alternate directions, and in the second case, that is, with the wires wound
spirally, I produce currents in continuous direction.
The movable cylinder 6 is put in motion by a motor of any description, and
whilst in motion initial magnetism is imparted to the soft iron teeth on the
movable cylinder b either by a temporary or secondary current from a battery or by
temporary magnetization. These teeth represent the poles of a number of small
magnets which induce a current in the fixed conducting wire o laid between the
teeth, which form the grooves of the fixed cylinder a in consequence of the
revolving of the movable cylinder in front of the said grooves.
The same action occurs with the fixed cylinder carrying the conducting wire o,
which induces electric currents in the conducting wire x, carried by the movable
cylinder, from which it results that the magnets of the movable cylinder act on the
wire on the fixed cylinder and reciprocally or vice versa, thus producing a double
effect and consequently a great increase in the intensity of the current. Thus the
mutual action of the movable magnetic system and of the fixed system may produce
two effects, that is to say, it may create either a continuous current through the aid

page_text: of a commutator placed concentrically on the axis c, which currents are gathered up
by the brushes or springs rubbing or pressing on the commutator whilst they are in
connection with the electrodes, or it may produce alternate currents.
My machine consisting therefore of cylinders presenting a number of small
magnets formed by the teeth of the soft iron rings or dises, has the great advantage
of producing a large number of inductive effects in a space relatively small and
with a less number of revolutions than has been hitherto necessary with other
machines.
In constructing my machines I may employ cylinders formed of one single piece,
provided with longitudinal grooves in the interior or on the exterior circumference
of the cylinders, in substitution for the union of a considerable number of the rings
or discs above described, and shown in the Drawing. I may also increase indefinitely
the number of cylinders as shown in Figure 6, that is to say, I may employ a fixed
exterior or outer cylinder a', an interior or inner fixed cylinder b', much smaller
than the first, and an intermediate movable cylinder 3 revolving concentrically
between the two others; in this case the movable cylinder 3 is provided with
teeth and grooves both on its inner and on its outer circumferences.
The cylinders are mounted in the following manner: Two discs x, x', form the
two ends of the inner fixed cylinder b¹, the mounting rods or long bolts, which are
screwed at their ends, passing through and being secured to the said discs by nuts.
The centre shaft a' also passes through these discs and is held tight by the
bearings b on the outside of the uprights d, d. The outer fixed cylinder a¹ finds a
lodgment on its lower side in the solid bearings f united to or forming part of the
base or bed plate g on which the machine or apparatus rests. This outer cylinder
is encircled or embraced by one or more metal bands which are bent at an angle at
their lower ends so as to be secured to the solid bearing f.
The intermediate movable cylinder 3 is also mounted on discs x2, x³, in a similar
manner to the inner fixed cylinder, that is to say, by means of screwed bolts and
nuts. These discs have a concentrically fastened hollow axis h capable of rotating
in the bearings i on the inner side of the uprights d, d, motion being com-
municated to the hollow axis by a pulley j. The cylinders are furnished with
inductive conductor wires as hereinbefore described.
For the purpose of establishing connection with these wires and their clamps
the wires from each cylinder are arranged as follows: Those from the inner
fixed cylinder are connected at their terminals by a copper band with two wires
laid in grooves made in one end of the shaft, and thence with the clamps h, k, as
shown. Those from the intermediate movable cylinder 3 are connected at their
terminals by a copper conducting wire k¹ with the pulleys fixed on the hollow
axis h, and thence by the brushes held by the clamps n, while those from the outer
fixed cylinder are connected at their terminals with the two clamps P, P.
The three pairs of clamps may be connected together either in series or parallel
to the inductive conductors in the three cylinders, as required, for intensity or
tension and then to the electrodes. On the hollow axis a commutator may also be
fixed for changing the direction of the current from alternate to continuous, or if
the machine be used as a motive power machine for changing a continuous into an
alternate current.
A modified method of mounting the cylinder consists in employing the con-
ducting wires to hold together the plates or discs forming the cylinder, thereby
dispensing with the iron rods or bolts. In this case the ends of the conducting
wires are screwed, the nuts pressing on oval washers furnished each with two holes
embracing the ends of the wires, holes being provided in the discs for the ends of
the conducting wires to pass through.
The washers at both ends of the wire are placed in opposite alternate order so
that the currents may flow to and fro throughout the whole length of all the con-
ducting wires.

page_text: And having now described the nature of my said Invention, and in what manner
the same is to be performed, I declare that I claim,-
First. The several arrangements of dynamo-electric machines as herein before
respectively described, and as shown in the annexed Drawings.
Secondly. I claim the special method hereinbefore described for producing a
multitude of small-magnetic poles in union in the form of an annular ring, and the
method of mounting them into a cylinder, whereby open passages are secured
for air to circulate in when the machine is in motion.
Thirdly. The method of multiplying electro inductive effects by winding the
conducting wires in a zig-zag manner, so that the flow of the current is in a
to and fro direction in front of the multitude of small magnets, whereby mutual
induction between the magnetic poles of the fixed cylinder or cylinders and the
wires of the movable cylinder or cylinders is established, and thereby the maximum
inductive power obtained.
In witness whereof, I, the said Isac Louis Pulvermacher, have hereunto set
my hand and seal, this Twenty seventh day of May, One thousand eight
hundred and seventy nine.
1. L. PULVERMACHER. (L.S.)