IMPROVEMENTS IN THE CONSTRUCTION OF INDUCTION APPARATUS
Year: 1886

page_text: Date of Application, 24th June, 1886.
Complete Left, 23rd Mar., 1887.
Complete Accepted, 17th June, 1887
RESERV
I, LUDWIG GUTMANN, of 1 Berkley Road, Regents Park, in the county of Middlesex
do hereby declare the nature of my invention for IMPROVEMENTS IN THE CONSTRUCTION
OF INDUCTION APPARATUS to be as follows:-
It has been demonstrated, that alternate currents can be economically used for
electric lighting by introduction of induction coils. Most of these coils are constructed
on the same principles. In the construction of my induction coil or apparatus
different principles may be adopted. The form of the coil or apparatus can be very
different. One construction for instance is the following: I take one or more wires
or ribbons of copper, brass or other suitable conductor, which forms the primary wire.
By the side of this cable, which is enveloped in a suitable insulator, are placed
insulated wires or ribbons of the same length as the primary cable. Now I wind
round this stranded cable iron wire or strips of iron in the direction at right
angles to the length of the cable in such a manner, that when I roll up the cable to a
flat spiral I am able to attach its commencement with the end, so that the iron forms
a complete circuit, or one wire without end. Or I place instead of this arrangement
iron spirals one beside the other and each independent of the next, round the cable.
Of spirals or bobbins made in this way I build up my induction coil; one spiral or
bobbin upon or round the other, of which the primary and secondary wires are each
connected in series or parallel depending on the work required.
In conduction coils up to the present, the iron was placed in identical position to
primary and secondary wire. But different parts of the same primary coil (and also
the secondary) are differently related to the core. For some parts of these are, by
the methods of construction adopted, necessarily farther away from the core than
others.
°
I can in my induction coil, as shown above, remedy this, so that each part of.
primary and secondary wire is equally related to the iron throughout the whole coil.
Another construction of the same kind is to wind each layer of primary and secondary
wire round the iron core, allowing the latter to project from each end of the spiral or
coil to a considerable extent..

page_text: The layers thus formed are superposed, one on the top or round the other, but each
layer is separated from the next by a sufficient amount of iron, which forms a closed
magnetic circuit, when its ends are connected.
As said above, my construction permits.me to make coils, which do not follow these
principles, coils in which there is not identity of relation-between the core on the one
hand and the primary and secondary wire on the other. For instance, one form has
a central primary conductor, surrounded by a number of secondary wires and theso
are covered by the iron. Of this cable flat spirals are made and superposed, then
connected into a coil.
Other coils of this kind are those, in which the primary wire in each spiral or
bobbin surrounds the secondary or vice versa and each layer is separated from the
next by iron; or 1 separate some or all convolutions or layers of the primary only or
the secondery by iron.
And lastly, I am able to arrange these superposed spirals or bobbins to have various
cross-sections; and in any given coil there may be spirals or bobbins of similar cross-
section throughout or bobbins which differ in cross-section from one another according
to special circumstances..
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I can construct this form of coil without any loss; and I am able to increase at will
the power of some spirals or bobbins or the whole apparatus by "separately exciting'
them by independent wires placed in some or all spirals or bobbins of the induction
coil or apparatus, the connections of which are made with the primary or secondary
wires, depending on special circumstances.
Dated thi 0411 J
L T 1000
COMPLETE SPECIFICATION.
Improvements in the Construction of Induction Apparatus.
I, LUDWIG GUTMANN of 1 Berkley Road Regents Park, in the County of Middlesex,
Instrument Maker, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and by the
following statement:
-
My invention for improvements in the construction of induction apparatus bas for
its principal object to obviate as nearly as possible the induction of the primary wires
and of the secondary wires of induction coils on themselves. In carrying my
invention into practical effect, I so arrange the different parts of the primary wire,
and also the different parts of the secondary wire, that their positions shall be as
nearly as possible the same with respect to the iron throughout the whole apparatus.

page_text: In the accompanying sheet of drawings
Fig. 1 is a plan of a layer or spiral for an induction coil constructed according to
this invention.
Fig. 2 is an elevation of induction apparatus constructed with the said layers or
spirals; and
Fig. 3 shows different forms of the section of a cable suitable for forming layers
or spirals constructed according to this invention.
Each layer or spiral C is formed from a cable consisting of two or more insulated
wires or ribbons of copper or other suitable electrical conductor laid parallel to one
another and surrounded by iron wire or ribbon wound in a direction at right angles
to the axis of the cable. This cable may have any suitable form in cross section,
several of such forms being shown in figs. 3, in all of which p represents the primary
wire or wires, s the secondary wire or wires, and d the iron core. It will readily be
seen from this construction that each unit of length of the primary wire, and also each
unit of length of the secondary wire, has practically a similar position with respect to
the iron core so that each unit of length of the cable gives the same efficiency. The
cable is wound into a flat spiral as shown in fig. 1 to form a layer on spiral C and the
ends of the iron wire of ribbon surrounding the primary and secondary wires are
joined so as to form a continuous magnetic circuit or this continuous circuit may be
replaced by independent helices of iron surrounding the primary and secondary wires
in a similar manner to the continuous wire. The induction apparatus is composed of
a number of superposed layers or spirals separated by any suitable insulating
material e so as to leave spaces for the circulation of air. The primary and secondary
wires of the layers or spirals C may each be connected together in any suitable way
according to the purpose for which the apparatus is required. Instead of the layers
or spirals being superposed, they may be arranged in one plane, one round the other,
they being suitably wound for this purpose.
Figs. 4 and 5 are similar views respectively to figs. 1 and 2.
In this modification, each layer or Bobbin C is formed with a single layer of primary
wire p and another layer of secondary wires arranged in any suitable manner with
a central space for the iron wire or strips which are passed through the central space.
and have their ends doubled back over the sides of the layer or bobbin and connected so
as to close the magnetic circuit or the strips f may be so connected as to form a helix.
A sufficient space, is, however left-as shown in the end view fig. 6, which is an
exaggerated end view of fig. 4-for the circulation of air. The secondary wire s is
shown wound on the central portion of the helix of primary wire.
Fig. 7 is a similar view to fig. 4 showing the secondary wires wound on the two
end portions of the helix of primary wire p.
Figs. 8, 9 and 10 are end views of layers or bobbins for induction apparatus con-
structed in a similar manner to the layers or bobbins shown in figs. 4, 5 and 6. In
these figures p is the primary wire, s the secondary wire and the iron.
Figs. 11 and 12 are similar views respectively to figs. 1 and 2 showing another
modification of induction apparatus constructed according to this invention.
In this modification each layer C comprises the parallel and insulated primary and
secondary wires wound so as to form an elongated spiral as clearly shown and the ironf
constructed in the form of coils of iron wire wound into a bobbin or of iron ribbon
wound into a helical form or of flat strips of iron formed into rings, the different
convolutions or rings being in all cases insulated from one another. In constructing
these layers, the primary and secondary wires are passed through the iron coils/
during the construction of the layers or the iron is wound or placed on the elongated
spirals. The induction apparatus is formed of the superposed layers C, the iron
coils being separated by any suitable insulating material e. It will be seen that in
this construction as in the construction shown in figs. 4 and 7 each layer C is provided
with iron both interiorly and exteriorly and that therefore each layer or convolution
or unit of length of the primary and secondary wires will give the same efficiency
throughout the whole apparatus.

page_text: Fig. 13 is a similar view to fig. 11 showing a slightly modified construction of
layer C. In this figure the iron cores are constructed out of cross shaped strips of
iron shown in fig. 14-consisting of two arms g, h rivetted together at their centres
to form a cross. The arms g are bent over as shown in fig. 15 to surround the two
sides of the elongated spiral and have their ends put into metallic connection with one
another. The arins are then bent up as shown in figs. 16 and 17 to pass through
the hollow space in the centre of the elongated Spiral and have their ends put into
metallic contact with the arms g. These pieces are superposed one on another until
there is a sufficient mass of iron, the different pieces being suitably insulated from
one another. The construction shown in figs. 11 and 13 are also suitable in cases
where the primary and secondary wires are wound independently of one another.
Each induction apparatus may be built up of one modification of layer, spiral or
bobbin or there may be one or more modified constructions of layers spirals or bobbins
in the same apparatus.
.
If it is desirable in any case to increase the power of the induction apparatus or of
any layer, spiral or bobbin of the apparatus, the action of the apparatus of layer,
spiral or hobbin may be supplemented by independent wires arranged in the layers,
spirals or bobbins at any convenient part which independent wires are connected with
the primary or secondary wires, or are supplied with a separate current according to
special circumstances.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed, I declare that what I claim is :-
1. The construction of layers or spirals for induction apparatus from a cable con-
sisting of the insulated and parallel primary and secondary wires surrounded by iron
wire or ribbon wound in a direction at right angles to the axis of the cable so that
each unit of length of the cable gives practically the same efficiency substantially as
described.
2. The construction of layers or bobbins for induction apparatus, each said layer or
bobbin consisting of one layer of primary wire and one layer of secondary wire and
being provided exteriorly and interiorly with iron substantially as described.
3. The construction of layers or spirals for induction apparatus consisting in
surrounding each layer or spiral of primary and secondary wires-whether the said
primary and secondary wires are in one cable or are wound separately-by iron coils
formed of bobbins of iron wire or of iron ribbon in the form of a helix or of concentric
iron rings or constructed out of cross shaped pieces of iron substantially as
described.
4. The construction of induction apparatus in which the iron cores are so arranged
as to separate the different layers formed either from a cable containing both the
primary and secondary wires or of separate primary and secondary wires substantially
as described.
5. The construction of induction apparatus substantially as described with reference
to the drawings.
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