Year: 1887

page_text: Date of Application, 12th July, 1887.
Specification Accepted, 19th Aug., 1887,
I, WILLIAM PHILLIPS THOMPSON, F.C.S. M.I.M.E. of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn, in the County of Middlesex, Civil
Engineer, 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 :-
The invention relates to apparatus employed for transforming alternating, pulsatory
or intermittent primary electric currents into alternating secondary or induced
currents. Devices for this purpose are technically termed inductoriums, transformers
or converters.
When an alternating, intermittent or pulsatory current is made to traverse an
electric conductor, a magnetic field is produced in its vicinity, the intensity and
polarity of which depends upon the character of the originating current, and any mass
of magnetizable material, for instance, iron, situated within this field becomes
magnetic. The alternate magnetization and de-magnetization of such a mass of iron,
or the reversal of its magnetic polarity in its turn tends to produce corresponding
electro motive forces in neighbouring conductors, which give rise to electric currents
when these conductors form a closed circuit; hence the mass of iron reacts
inductively both on the conductor traversed by the originating or primary current as
well as upon any other conductor within its influence. An independent conductor
thus placed within the inductive field is called a secondary conductor.
In the accompanying drawings, figure 1 is an end view (the coil being in section)
of one form of a converter, and figure 2 is a side view of the same; Figure 3 is a
detached view (drawn to a reduced scale) showing two of the plates of which the core
is composed. Figures 4, 5 and 6 illustrate a modified form; Figures 7, 8 and 9
illustrate a containing box,

page_text: Referring to the figures 1, 2 and 3, PS represent the conducting wire or wires
which constitute the coil of the converter. Two similar coils P and S are shown in
the section (figure 2) as separated from each other by an intervening insulating
space but a single coil only may be employed, which may serve for both the
inducing and the induced currents. In such case, the space occupied by the primary
and secondary coils, P and S (figure 2) is filled with the primary coil alone. The
core A is composed of a number of plates a a of soft iron, which may with advantage
be made very thin. These plates are electrically and magnetically separated from
each other by intervening sheets bb of non-conducting and non-magnetic material,
thin linen paper of good quality being found to serve an excellent purpose. The
sheets of paper may be secured by paste or other convenient means to one or both
sides of each plate, before it is placed in the converter. Each individual plate is
formed with three lateral tongues projecting in the same direction (figures 1 and 3)
so that the configuration of the finished plate resembles that of the letter E. The
electric conductor or conductors, having first been wound in an oval- or flattened coil
preferably of rectangular cross section, the plates a a are inserted so that the middle
tongue occupies the space within the coil, while the exterior tongues together
with the body of the plate, surround the exterior of the coil on three sides. In
assembling the plates to form the core, each alternate plate is inserted from the
opposite side, and in this way, with an even number of plates, the total mass of iron
necessarily becomes symetrically distributed on every side of the mean axis of the
transverse section of the coiled conductor or conductors.
The plates are securely bound together into a mass to form the core by end frames
or heads H and H2, connected together by longitudinal bolts h h.
In some instances it may be found desirable to extend the ends of the outer arms
on the soft iron plates toward each other or toward the central tongues, as will be
described with reference to figures 4, 5 and 6. Referring to these figures, the core
is composed in this instance of thin iron sheets or plates a a alternate ones of which
are magnetically separated from each other by the thin sheets bb of non-conducting
material.
In preparing the plates a a, rectangular sheets are stamped with two holes e¹ e²,
which are themselves preferably rectangular in form, and they are of such size as to
receive the primary and secondary coils P and S.
Each opening e¹ and e² is cut open as shown at fl and f respectively, the cuts
being preferably in a line with the inner edges of the corresponding openings. It
may not always be found necessary to have the cuts exactly in line with these edges,
but one or both of them may be in a diagonal direction as indicated by the dotted
lines (figure 6). This has the advantage of sharpening the tongue f and making it
more easy to insert it in the coils.
The central tongue f is designed to extend through the interior of the coils. The
separate plates are then applied to the coils by springing the portions f³ and f
backward, in the manner shown in figure 6, then thrusting the tongue f' through the
coils and allowing the plate to return to its normal position. The iron, which it is
found preferable to use, is so thin that the operation may be very readily performed
by hand, without the use of machinery.
For the purpose of breaking joints, the alternate plates a a are preferably inserted
from opposite sides, so that the slits flf of one plate are against the solid portions
of the two adjacent plates. It is preferred to place plates so that the bare metallic
surfaces of two plates rest against each other, and the opposite insulated surfaces of
these plates rest against corresponding insulated surfaces of their contiguous plates.
The insulated surfaces may, however, all lie in one direction.
In building the converter the plates are temporarily pressed together as may be
found necessary by clamps or in any convenient manner.
The plates, when as many as practicable have been inserted, should be tightly
pressed against each other, and to accomplish this two plates H¹ and H2 are placed at
the respective ends of the converter and bound against the same by four bolts h¹, h², h³
and The plates Hand H³ are preferably of cast brass or iron;. surrounding the

page_text: projecting ends of the coils and resting against the edges of the end plates. To render
the complete converter as compact as possible, the corners of the plates a a are cut off
to allow room for the bolts h¹, h², h² and h¹.
The iron thus removed is of little or no importance as regards the operation of the
converter.
The primary and secondary coils are separately wound and wrapped with suitable
insulating material, and they may be usually with advantage separated from each
other a slight distance by suitable insulating material, such for instance, as leatheroid
or white fibre. Narrow strips of the same material may also be placed between the
remaining sides of the coils and the surrounding metal."
In the figures, bands a³ of cotton cloth or canvas are shown as wound upon the
coils and coated with shellac or other non-conducting material. The coils are then
placed side by side, in some instances separated by strips or plates of leatheroid or
white fibre or other suitable non-conducting substance as shown at a². Narrow strips
of the same material may be bound against the sides of the coils, as shown at a¹ a¹.
The core of soft iron is then applied.
By means of these separate coverings, the insulation between the two circuits is
rendered more perfect, and a great reduction of the static capacity of the core is
secured, since only the small external surfaces are presented to each other, and these
are some distance from each other; and also the converter is much more easily
constructed and different standard coils may be placed in different converters, where
different ratios of conversion are desired.
The box is illustrated in figures 7, 8 and 9. The main portion of the box is formed
in two parts, one of which is designed to be secured at the top and bottom to suitable
portions, such for instance as the cross-arms placed upon poles in the manner adopted
in constructing telegraph lines; while the other section of the box is secured to the
first named section and carries two compartments, the one designed to receive the
terminals of the primary and the other the terminals of the secondary coils of
the converter. These compartments respectively contain circuit controlling devices
upon plates of non-conducting material, and are closed by transparent plates which
permit them to be inspected. Metallic discs preferably cover the plates and protect
them from injury. A represents the back section and A' the front section of the
box, and B the converter placed within the box. The section A¹ is constructed with
lateral lugs c¹, c², c³ and c³, for convenience in securing the same to cross arms c
and c or other convenient supports. A lateral flange or lug c rests upon the arm or
support c. The arms and may form suitable supports for conveying the
primary and secondary conductors, being properly distanced for that purpose.
The front section A³ is bolted or otherwise securely fastened to the section A¹,.as
indicated at c c. This section A² carries two compartments D' and D' formed by
annular webs or lugs being thrown out from the casting. The terminals of the
primary coil B of the converter are led through suitable openings P' in the casting,
into the compartment D'. The terminals of the secondary coil S are led in like
manner through openings S¹ into the compartment D. These compartments are
preferably constructed with inwardly projecting lugs d d, against which there are
fastened non-conducting plates e¹ and e. These are of fibre, hard rubber or other
suitable material. The primary conductors are fastened to bolts or coupling screws f¹
(only one of which is shown), this being fastened to and extending through the
plate e¹. The terminals of the secondary coil are in like manner connected upon the
under side of the plate e with coupling screws f. The connections are continued
from these screws, through fusible switch plugs or strips g³ to switch plates h³ and
respectively. These plates are connected, at will, by corresponding switch plugs j
and k with other contact or switch plates m³ and n². The conductors o' o' lead from
the plates m² and n³ respectively through suitable openings w³ ³, in the lower side of
the plate or web forming the compartment D³, such openings being lined with fibre
or other suitable non-conducting tubes or thimbles as shown at r, r. For the purpose
of completely insulating the fusible strips and their connected conductors from each
other, insulating material is placed across the compartment D³, thus preventing an

page_text: accidental short-circuit being formed. The openings P¹ and S¹ are also preferably
constructed with non-conducting thimbles p¹ and s¹,serving to prevent contact between
the iron of the case and the conductors leading through the openings.
The box or compartment D' is in like manner equipped with circuit controlling
and safety devices as indicated at g₁, i¹, j¹ and n', connected with the respective
terminals of the primary coil, and the primary conductors lead through suitable
openings to at the bottom of the compartment.
The outer ends of the compartments D' and D' are closed securely by glass plates T¹
and T respectively, and these are preferably held in position by annular clamps t¹
and 2 and rubber washers 3 and 4. The plates of glass allow the circuit connections
to be inspected without opening the box. For their better preservation, however,
discs u¹ and u² are preferably fastened in front of the plates in such manner that they
may be easily removed or swung aside when desired.
The converter, as shown in the present instance, consists of the two coils P and S
surrounded by plates of iron a, the plates being secured together by bolts h³, h³. The
converter box is constructed to conform in general shape to the converter, and when
placed in position the ends of the rods holding the plates, rest upon the shoulders 6³
and 64.
For the purpose of preventing the wires of the coil from coming into contact with
the iron of the case, suitable shields y and y may be made to project over the ends of
the coils, such shields constituting hoods formed upon plates vv fastened to the ends
of the core formed by the plates a.
Having now particularly described and ascertained the nature of the said Invention,
and in what manner the same is to be performed, as communicated by my foreign
correspondent, I declare that what I claim is:
1. A core composed of E-shaped plates, electrically and magnetically separated
from each other, and symmetrically disposed about a coiled conductor, as set forth.
2. The combination with a coiled conductor, of a mass of soft-iron composed of
detached plates, each plate being provided with three projecting tongues, one situated
within and the other without the coil, as set forth.
3. The combination of the primary and secondary coils of a converter, and a core
composed of thin flexible plates of soft iron, each formed with two holes, the metal
about each hole being cut open for receiving the coils, substantially as described.
4. Metal plates for forming cores for electric converters constructed with two
openings, the metal around each opening being cut apart.
5. An electric converter consisting of the primary and secondary coils and a series
of soft iron plates having holes for receiving the respective sides of the coils, the
metal surrounding the holes being cut apart upon opposite sides in the alternate
plates.
6. An electrical converter consisting of primary and secondary coils, having a core
composed of thin plates of soft iron, each plate having two holes, the metal about
each hole being cut open for receiving the coils, and non-magnetic material between
alternate plates.
7. A core for electric converters consisting of thin plates of soft iron each having
two openings, and each two plates being magnetically separated from the adjacent
plates but in magnetic contact with each other.
8. An electric converter consisting of primary and secondary coils and a core of
soft iron plates, each constructed with two openings for receiving the coils, the metal
about each opening being cut through and the central tongues thus formed inserted
within said coils from opposite sides, and sheets of non-magnetic material between
the alternate plates.
9. The combination with the primary and secondary coils of a converter, separately
wound and covered with insulating material, of plates of non-conducting material
between said coils, strips of non-conducting material extending along the sides of the
coils, and a core of soft iron surrounding the coils, leaving air-spaces between said
strips.

page_text: 10. In an electric converter, the combination with the primary and secondary coils
separately wound, of plates of insulating material between the coils and strips of
insulating material extending along the sides of the coils and separating the same
from the surrounding core, substantially as described.
11. The combination, in an electric converter, of a core built up of plates or sheets
of soft iron magnetically insulated from each other and having rectangular openings,
primary and secondary coils within said openings, and strips of insulating substance
separating the coils from the core, substantially as described.
12. The combination with the core of an electric converter, of primary and
secondary coils therefor, separately wound and covered with separate insulation,
substantially as described.
13. In an electric converter, primary and secondary coils separately wound, and
a covering of insulating material applied to each coil independently of the other,
substantially as described.
14. The combination of the primary and secondary coils, of an electric converter,
said coils being separately wound and separately insulated and placed side by side,
and a core of soft iron to which the coils are applied.
15. A converter box constructed in two sections, the one provided with means for
securing it to supports, and the other having two separate compartments, for
receiving the primary and secondary circuit-controlling devices.
16. A converter box constructed in two parts, the one being provided with
separate compartments formed by lateral webs, non-conducting plates within said
compartments, and circuit-controlling devices carried upon said plates.
17. The combination with a box for containing an electric converter, of two
independent compartments integral therewith for receiving the primary and secondary
terminals respectively, non-conducting plates within said compartments, independent
circuit-controlling devices for the respective primary and the respective secondary
conductors carried by said plates, and non-conducting plates between the respective
circuit-controlling devices in each compartment.
18. The combination with a box for containing an electric converter, of inde-
pendent compartments integral therewith, for containing the primary and secondary
circuit-controlling devices, transparent plates closing said compartments and protecting
discs outside said plates.
19. The combination with an electric converter, of supports for the primary and
secondary conductors respectively, and a box containing the converter secured at one
end to the support of the primary conductors and at the other end to the support of
the secondary conductors.
20. The combination with an electric converter of supports for the primary and
secondary conductors respectively, a box containing the converter secured at one end
to the support of the primary conductors and at the other end to the support of the
secondary conductors, a compartiment for receiving the terminals of the primary coils
of the converter, a second compartment for receiving the terminals of the secondary
coils of the converter, and openings at the bottom of the respective compartments for
receiving conductors leading to the primary and secondary coils respectively.
Dated this 11th day of July 1887.
WM. P. THOMPSON & Co.,
Agents for the Applicant.