Improvements in Electrical Transformers.
Year: 1891

page_text: Date of Application, 25th Mar., 1891
Complete Specification Left, 21st Dec., 1891-Accepted, 23rd Jan., 1892
PROVISIONAL SPECIFICATION.
Improvements in Electrical Transformers.
I, ARCADIUS POLESCHKO of 35 Baskoff Pereulok, St. Petersburg, in the
Empire of Russia, Gentleman, do hereby declare the nature of this invention to be
as follows:-
All existing transformers may be classed in two groups in the one (the Ruhmkorff
coil and the Gaulard and Gibbs transformer) the iron core is in the form of a
cylinder; in the other the iron core is in the form of a closed geometrical figure;
annular (in the Zipernowski, Deri and Blaty) or otherwise (in the Westinghouse,
Ferranti &c.). In transformers of the first group the lines of force generated in the
iron core by the action of the primary helix, are given off as a bundle from the
north pole and proceed to the south pole across the outer space where they form
closed curves of all possible radii ; the secondary coil in this case is in the inter-
mediate space between the iron core and the exterior system of lines of force.
In transformers of the second group all the lines of force generated in the iron
core by the action of the primary coil remain entirely in the core itself without
appearing at the exterior; these lines of force, remaining in the iron core, can only
pass in the interior of the spirals of the secondary coil (in the case of an interior
core) or they will encircle the outer secondary coil (the outer core). In both cases
the lines of force never touch the secondary helix itself.
In transformers of the first group as well as the other, the secondary coil is not
traversed by all the lines of force which circulate in the iron, it is only a small
portion of the lines of force, which detach themselves so to speak from the general
magnetic flow which reach the secondary coil in closing along short elementary
curves. In other words, in both cases the secondary coil is influenced not by the
magnetic flow in the iron core, but directly by the current in the primary coil; in
arrangements of this kind, the iron core, although it augments the inductive
capability of the primary coil absorbs quite unproductively too great a number of
lines of force in itself.
Such is the condition of things when the primary circuit is closed and the
magnetic flux is produced. The nature of the lines of magnetic force and their
mode of formation is not at present well determined. According to Poyting and
other physicists the energy of magnetic force flows from the exterior and when the
current is on, it distributes itself in the iron core by the lateral surface of the
cylinder or ring. But the mode of grouping of these lines at the moment of their
entrance into the iron core, and their distribution on the surface of the core is
unknown. From this point of view and admitting that the most favourable moment
of induction will be precisely that at which the force of the magnetic energy flows
from the exterior into the iron core by its lateral surface, it remains nevertheless
improbable that in transformers of the two groups mentioned, the lines of force can
at the moment of their introduction into the iron, traverse in its totality the
secondary coil; the greater quantity will certainly pass outside the secondary coil.
Still the amount of induction depends upon the intersection of the coil to be
influenced, (the secondary coil in the transformers) by the lines of magnetic force,
and the effect of induction becomes greater as the number of lines of force which
intersect with the coil increases. It follows that a real advantage would be
obtained by an arrangement of the apparatus such that the magnetic flux which
circulates in an iron core shall pass in its totality across the secondary coil.
My arrangement of transformer (Figures 1 and 2) fulfils this condition. In this
apparatus the secondary helix +12+, is influenced in the first place by the current
n the primary helix ±₁₁ and in addition by the whole of the magnetic flux which

page_text: 18 developed in the iron core A A by the action or the primary con upon this core.
In transformers on my system as in dynamo electric machines, the loss of magnetism
in the air is only very small and almost the whole of the lines of force which flow
in the. iron core, encounter the secondary coil in their course and traverse it at
right angles.
ARRANGEMENT OF THE TRANSFORMER.
The core consists of blades or thin plates cut (by means of a stamp) from sheet
ron or soft cast iron. The plates A A the shape of which is shewn in Figure 1
are arranged in the form of a ring and inserted at top and bottom into two insulating
hubs B B.
The primary coil ± is arranged in the vertical cavity ab of the core
(Figure 1), and the secondary coil +2, is arranged outside the first in form
of a flat ring of small height but of great breadth (in the direction of the diameter
of the ring). The secondary coil of this shape is placed in a narrow channel cd in
the core.
The ends of the two coils are led to corresponding terminals on the
insulating hub.
By this arrangement the lines of force meet in their circuit a channel cd and this
channel although containing air, being narrow and long only slightly increases the
resistance of the magnetic circuit. This channel also which cuts the mass of the
core across the direction of the lines of magnetic force, increases very considerably
the rapidity of demagnetisation and weakens the effect known by the term
hysteresis in this way it lessens the loss of energy expended in internal work in
transformers of other systems.
The thin iron plates of the core are insulated one from another by air. This
arrangement of core has the double advantage (a) of completely avoiding Foucault
currents and (b) of increasing the cooling surface. In short in its outer shape my
transformer resembles an air heating stove or a stove with exterior fins; all
the heat developed by the action of the currents in the primary and secondary
coils, is dissipated in the atmosphere radiating from the enormous lateral surface
of the plates of the core and by their fins. The primary and secondary coils are
able to carry a current of very considerable volume without producing injurious
heating of the transformer.
Dated this 25th day of March 1891.
CARPMAEL & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Electrical Transformers.
I, ARCADIUS POLESCHKO of 35 Baskoff Pereoulok, St. Petersburg in the
Empire of Russia, Gentleman, 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 :-
All existing transformers may be classed in two groups in the one (the Ruhmkorff
coil and the Gaulard and Gibbs transformer) the iron core is in the form of a
cylinder; in the other the iron core is in the form of a closed geometrical figure;
annular (in the Zipernowski, Deri and Blaty) or otherwise (in the Westinghouse,
Ferranti &c.). In transformers of the first group the lines of force generated in
the iron core by the action of the primary helix, are given off as a bundle from the
north pole and proceed to the south pole across the outer space where they form
closed curves of all possible radii; the secondary coil in this case is in the
intermediate space between the iron core and the exterior system of lines
of force.
In transformers of the second group all the lines of force generated in the iron
core by the action of the primary coil remain entirely in the core itself without

page_text: appearing at the exterior; these lines of force, remaining in the iron core, can only
pass in the interior of the spirals of the secondary coil (in the case of an interior
core) or they will encircle the outer secondary coil (the outer core). In both cases
the lines of force never touch the secondary helix itself.
In transformers of the first group as well as the other, the secondary coil is not
traversed by all the lines of force which circulate in the iron, it is only a small
portion of the lines of force, which detach themselves so to speak from the general
magnetic flow which reach the secondary coil in closing along short elementary
curves. In other words, in both cases the secondary coil is influenced not by the
magnetic flow in the iron core, but directly by the current in the primary coil; in
arrangements of this kind, the iron core, although it augments the inductive
capacity of the primary coil absorbs quite unproductively too great a number of
lines of force in itself.
Such is the condition of things when the primary circuit is closed and the
magnetic flux is produced. The nature of the lines of magnetic force and their
mode of formation is not at present well determined. According to Poyting and
other physicists the energy of magnetic force flows from the exterior and when the
current is on, it distributes itself in the iron core by the lateral surface of the
cylinder or ring: But the mode of grouping of these lines at the moment of their
entrance into the iron core, and their distribution on the surface of the core is
unknown. From this point of view and admitting that the most favorable moment
of induction would be precisely that at which the force of the magnetic energy
flows from the exterior into the iron core by its lateral surface, it remains never-
theless improbable that in transformers of the two groups mentioned, the lines of
force can at the moment of their introduction into the iron, traverse in their totality
the secondary coil; the greater quantity will certainly pass outside the secondary
coil. Still the amount of induction depends upon the intersection of the coil to be
influenced, (the secondary coil in the transformers) by the lines of magnetic force,
and the effect of induction becomes greater as the number of lines of force which
intersect with the coil increases. It follows that a real advantage would be obtained
by an arrangement of the apparatus such that the magnetic flux which circulates in
an iron core shall pass in its totality across the secondary coil.
My arrangement of transformer (see Figures 1 and 2 of the drawings left with
my Provisional Specification) fulfils this condition. In this apparatus the secondary
helix, is influenced in the first place by the current in the primary
helix, and in addition by the whole of the magnetic flux which is developed
in the iron core A A by the action of the primary coil upon this core. In trans-
formers on my system as in dynamo electric machines, the loss of magnetism in the
air is only very small and almost the whole of the lines of force which flow in the
iron core, encounter the secondary coil in their course and traverse it at right
angles.
ARRANGEMENT OF THE TRANSFORMER.
The core consists of blades or thin plates cut (by means of a stamp) from sheet
iron or soft cast iron. The plates A A the shape of which is shewn in Figure 1
are arranged in the form of a ring and inserted at top and bottom into two insulating
hubs B B.
The primary coil +4₁₁ is arranged in the vertical cavity ab of the core
(Figure 1), and the secondary coil +2, is arranged outside the first in form
of a flat ring of small height but of great breadth (in the direction of the diameter
of the ring). The secondary coil of this shape is placed in a narrow channel cd in
the core.
The ends of the two coils are led to corresponding terminals on the
insulating hub.
By this arrangement the lines of force meet in their circuit a channel cd and this
channel although containing air, being narrow and long only slightly increases the
resistance of the magnetic circuit. This channel also which cuts the mass of the
core across the direction of the lines of magnetic force, increases very considerably

page_text: the rapidity of demagnetisation and weakens the effect known by the term
hysteresis; in this way it lessens the loss of energy expended in internal work in
transformers of other systems.
The thin iron plates of the core are insulated one from another by air. This
arrangement of core has the double advantage (a) of completely avoiding Foucault
currents and (b) of increasing the cooling surface. In short in its outer shape my
transformer resembles an air heating stove or a stove with exterior fins; all the
heat developed by the action of the currents in the primary and secondary coils, is
dissipated in the atmosphere radiating from the enormous lateral surface of the
plates of the core and by their edges. The primary and secondary coils are able
to carry a current of very considerable volume without producing injurious heating
of the transformer.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A transformer such that the induction in the secondary coil is caused not only
by the current in the primary coil but principally by the magnetic flux which is
developed in the iron core under the influence of the primary coil; this magnetic
flux both in its increase and decrease constantly in its passage encountering the
secondary coil at right angles with the whole of the lines of force which compose
it, with the exception of a certain loss in the air such as takes place in dynamo
electric machines.
2. A transformer characterised by the arrangement of the core, consisting of
plates of iron assembled into the form of a ring and isolated the one from the other
by air, these plates each having a vertical cleft and another which is horizontal to
receive the primary and secondary coils which are arranged in such manner that
the magnetic flux set up in the core traverses in its totality and at right angles the
convolutions of the secondary coil, substantially as is described above.
3. A transformer substantially as is represented by the annexed drawings.
Dated this 1st day of December 1891.
ARCADIUS POLESCHKO.