Improvements in Electrical Transformers.
Year: 1890

page_text: Date of Application, 16th May, 1890
Complete Specification Left, 11th Feb., 1891-Accepted, 14th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Electrical Transformers.
I, JOHN AUGUSTINE KINGDON, of 29, Marlborough Hill, St. John's Wood,
London, in the County of Middlesex, Electrical Engineer, do hereby declare the
nature of this invention to be as follows:-
:-
I construct the cores of my improved transformers of a number of thin plates of
soft iron piled one above another. These are of the same width, but at intervals
one or two are longer than the rest.
Insulating material is wrapt round the pile of plates, and primary and secondary
coils of insulated conducting wire are then wound outside the insulating material.
The primary & secondary coils are preferably split up into a number of sections
placed alternately and separated by insulating material.
Outside the wire coils and separated from them by insulating material or an air
space. are wound a number of coils of thin iron strip or ribbon. These coils are in
contact with and wound round the projecting ends of the iron cores and are at right
angles to the wire coils. They are separated from one another by the longer
plates of the cores. Bolts, pass through these plates, outside the ribbon coils and
clamp the whole together.
Metal covers are bolted over the projecting wire coils or the transformer is
placed in a metal box, in which case I sometimes fill the space between the iron
ribbon coils and the box with cement, which serves to conduct heat away from the
transformer to the metal of the box.
The iron coils may be of wire instead of ribbon.
COMPLETE SPECIFICATION.
Improvements in Electrical Transformers.
I, JOHN AUGUSTINE KINGDON, of 29, Marlborough Hill, St. John's Wood,
London, in the County of Middlesex, Electrical Engineer, do hereby declare the
nature of this invention, and in what manner the saine is to be performed, to be
particularly described and ascertained in and by the following statement:
Fig. 1. of the accompanying drawings is an elevation, Fig 2 is a plan and Fig. 3.
is a sectional elevation of my improved transformer.
Figs. 4 and 5 are plans of parts of the transformer.
Figs. 1. 2. 3. 4 and 5 of Sheet 1 are all to the same scale and the same parts in
each figure are indicated by the same letters.
·
In Sheet 2 Fig 6 is a plan and Fig. 7 is a sectional elevation of my transformer
cemented into an iron box according to the second part of my invention.
I construct the cores of my improved transformers of a number of soft iron plates.
The majority of these plates A, are of the shape and proportions shown in Fig. 4.
but some of the plates B, say 10 to 15 per cent. are longer than the rest of the
plates A. and punched with holes as shown in Fig. 5. The core is built up by
taking one of the plates B, then say 8 of the plates A and piling them over the
first plate in the position shown in dotted lines in Fig. 5. The plates may be
[Price 8d1

page_text: varnished or separated by thin paper. A second plate B is then added, then eight
more A plates and so on. The pile of plates is clamped together and ebonite or
other insulating material I is wrapt round the pile. The primary coils P & secon-
dary coils S which may be of any convenient number are of insulated copper wire
and are wound alternately outside the insulating material I. The coils P & S are
separated by insulating shields R. The coils are connected up in series or parallel
as may be desired. To make a complete magnetic circuit I wind round the pile of
plates forming the core and the primary & secondary coils, thin iron tape or
ribbon T, preferably varnished, and of such a width as to fit in between the long
plates B. The iron tape forms a number of coils T separated from one another by
the long plates B. The short plates A are of such a length as just to fit inside the
coils of iron tape T.
In some cases instead of winding the coils of iron tape T outside the core and the
copper wire coils, I prepare them separately & build up the transformer by placing
one plate B in its place at the bottom of the copper coils, then the right number of
short plates A. then place an iron tape coil outside the copper coils, and then
put another long plate B and so on until the space inside the copper coils is filled
up with iron plates. The bolts C passing through the holes stamped in the plates B
and outside the coils of iron tape T clamp the transformer together.
In some cases I bolt metal covers over the projecting ends of the primary &
secondary coils P and S, provided with holes bushed with insulating material to
enable the ends of the coils to be brought through or provided with terminals.
I prefer however to place the transformer in a metal box D, Figs. 6. and 7. of
Sheet 2 of the drawings. The box D is provided with a ledge L, the shape of
which is shown by the broken line in Fig. 6. which is a plan of the arrangement
with the cover. E removed. The lowest iron tape coil T rests on this ledge L and
pockets are provided for the bolt ends C C C C. The spaces between the tape
coils T are stopped with red lead or putty so as to be watertight and thin Portland
or other cement is poured into the space between the tape coils T and the shell of
the box D. The cement fills the space between the transformer and the box D, as
shown at F in Fig. 7. but care is taken that it does not reach the coils of copper
wire which are in the air spaces G at the top and bottom of the box. In order to
allow for the circulation of air round the copper coils I sometimes provide tubes H.
Figs. 6 & 7. cast in or fitted to the box, such tubes not being filled with the cement.
The cement serves to secure the transformer in the box and to conduct heat away
from the iron tape through the iron box to the surrounding air.
A cover E is fitted watertight on the top of the box and air holes and holes for
the wires are also provided as desired.
Iron wire may be wound outside the coils instead of tape.
I do not confine myself to the exact proportions or numbers of coils or plates
shown in the drawings as these may be varied, nor to the type of box shown in
Sheet 2 as this may be modified to suit other transformers.
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. An electrical transformer having its core constructed of iron plates some of
which are longer than & project beyond the rest, and having its magnetic circuit
completed by winding iron tape or wire outside the primary & secondary coils
between the projecting iron plates substantially as hereinbefore described & illus-
trated in the accompanying drawings.
2. The combination in a transformer of short iron plates with primary &
secondary coils, long iron plates and coils of iron tape or wire.
3. The combination in a transformer of short iron plates separated at intervals
by long iron plates with coils of iron tape or wire and coils of copper tape
or wire..

page_text: 4. Constructing the core of a transformer of a number of iron plates some of
which project beyond the rest substantially as described.
5. Cementing a transformer into a metal box substantially as described.
6. The combination of an electrical transformer with a metal box into which it is
cemented.
.