Improvements in the construction of transformers
Year: 1888

page_text: We GISBERT KAPP, of Stanley Villa, Stanley Road, Wimbledon in the county of
Surrey, WILLIAM HENRY SNELL of "Lamorna," Oxford Road, Putney in the
county of Surrey, and JULIAN MONEY VERNON MONEY-KENT, of Connaught Mansions,
Westminster in the county of Middlesex, Electrical Engineers, do hereby declare the
nature of this invention to be as follows:-
Letters Patent No. 1904 of 1887 were granted to us for certain "Improvements
in the construction of transformers" which improvements comprise inter alia
composing the cores of transformers of a number of thin metal plates insulated
and placed face to face and formed of U or shape and sometimes shape,
or where ventilation may be dispensed with of shaped plates, the coils being
placed over the vertical sides so as to be readily detachable, and the magnetic
circuit being completed by a cover or armature (also composed of thin iron plates)
of suitable form placed upon the top of the said vertical sides and making good
magnetic contacts therewith.
It has been found that while important advantages accrue from this construction,
yet when transformers of large size are required there is expense and difficulty in
stamping plates of the required size of the sections specified and also a considerable
waste of material.
The object of the present improvements is to remedy these defects, and the inven-
tion consists in so forming and disposing the metal cores that the plates may be more
readily and economically made while the advantage of readily detaching the cores is
retained. To this end we form the cores as before of groups of thin iron plates
insulated and placed face to face, but instead of the shapes specified in our said
prior patent we use rectangular plates which may be cut without any waste
whatever in suitable lengths from strips. hoops, tapes, or ribbons or iron of the
required widths. We dispose these lengths on edge in horizontal groups of suitable
dimensions, above, below, and passing through the centre of the coil or coils at right
angles to the direction of the winding thereof, suitable spaces for ventilation being

page_text: provided longitudinally in each such horizontal group if required. We .complete
the magnetic circuit between such horizontal groups by transverse or vertical
groups of suitable dimensions similarly constructed and interposed at either ends of
the said longitudinal groups outside the coils: suitable means may in some cases be
provided for decreasing noise and heating at the joints, such as interposed sheets
of asbestos or other insulating material. The quantity of metal employed in the
different members is so proportioned and disposed as to obtain approximately the
same induction. (number of lines of magnetic force per square centimetre of cross
sectional area) througbout the magnetic circuit, except at the abutting faces which
may be made of rather larger area than corresponds to this rule with the object of
reducing as far as possible the magnetic resistance of the joints. The plates forming
the members may be held together by bolts, clamps, insulated wrapping or in other
usual manner; where bolts are used the ends of the horizontal members are carried
beyond the transverse members and the said bolts inserted outside the magnetic
circuit.
The whole is placed in a frame capable of being securely bolted together and the
usual connections for the leads are provided.

page_text: Improvements in the Construction of Transformers.
We GISBERT KAPP, of Stanley Villa, Stanley Road, Wimbledon, in the county of
Surrey, WILLIAM HENRY SNELL, of "Lamorna," Oxford Road, Putney in the county
of Surrey, and JULIAN MONEY VERNON MONEY-KENT, of Connaught Mansions,
Westminster, in the county of Middlesex, Electrical Engineers, 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 :-
Letters Patent No. 1904 of 1887 were granted to us for certain "Improvements in
the construction of transformers" which improvements comprise inter alia composing
the cores of transformers of a number of tin metal plates insulated and placed face
to face and formed of U or shape and sometimes ☐☐ shape, or where ventilation
may be dispensed with of shaped plates, the coils being placed over the vertical
sides so as to be readily detachable and the magnetic circuit being completed by a
cover or armature also composed of thin iron plates of suitable form placed upon
the top of the said vertical sides and making good magnetic contacts therewith.
It has been found that while important advantages accrue from this construction,
yet when transformers of large size are required there is expense and difficulty in
stamping plates of the required size of the sections specified and also a considerable
waste of material.
The object of the present improvements is to remedy these defects and the inven-
tion consists in so forming and disposing the metal cores, that is to say, the active
iron parts of the magnetic circuit, that the plates may be more readily and
economically made while the advantage of readily detaching the coils is retained.
To this end we form the cores as before of groups of thin iron plates insulated and
placed face to face, but instead of the shapes specified in our said prior patent we
use rectangular plates which may be cut without any waste whatever in suitable"
lengths from sheets, strips, hoops, tapes, or ribbons of iron of the required widths:
We dispose these lengths on edge in horizontal groups of suitable dimensions above,
below, and passing through the centre of the coil or coils at right angles to the
direction of the winding thereof, suitable spaces for ventilation being provided
longitudinally in each such horizontal group if required. We complete the magnetic
circuit between such horizontal groups by transverse or vertical groups of suitable
dimensions similarly constructed and interposed at either ends of the said longitudinal
groups outside the coils. Suitable means may in some cases be provided for
decreasing noise and heating at the joints such as interposed sheets of asbestos or
other insulating material as illustrated drawings annexed hereto.
.7
The quantity of metal employed in the different members going together to form
the magnetic circuit is so proportioned and disposed as to obtain approximately the
same induction (number of lines of magnetic force per square centimetre of cross
sectional area) throughout the magnetic circuit, except at the abutting faces between

page_text: the longitudinal and transverse groups of plates, which may be made of rather larger
area than corresponds to this rule with the object of reducing as far as possible the
magnetic resistance of the joints.
The plates forming the members may be held together by bolts, clamps, insulated
wrapping or in other usual manner; where bolts are used the ends of the horizontal
members are carried beyond the tranverse members and the said bolts inserted outside
the magnetic circuit.
The whole of the iron forming the magnetic circuit and the coils also are placed in
a frame capable of being securely bolted together and the usual connections for the
leads are provided.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation of a transformer the frame being partly removed at
right hand end and the casing and other parts being shown in section. Figure 2 is a
cross section on line ab figure 1. Figure 3 is an end elevation with coils removed.
Figure 4 is a side elevation partly in section of an alternative form. Figure 5 is a
plan (on the left) of the casing, on the right of same and end of bed in section.
Figure 6 is a cross section on line c d of figure 5. In all those figures similar letters
are used to indicate similar parts. A A, B B are the groups of iron plates forming
the magnetic circuit arranged as described above and disposed in longitudinal and
transverse directions respectively. P and S are the primary and secondary coils
respectively. These may be arranged as illustrated or their positions may be varied
as desired. The coils are bound with tape and separated where required by
ebonite e or other suitable substance. CC figures 2 and 3 are ventilation spaces
between the neighbouring groups of iron plates.
In the arrangement illustrated in figures 1, 2 and 3 the plates composing
the transverse groups B are held together by clamps K and screws k k and the
longitudinal groups A by the bolts L L. The plates A are extended beyond the
members B and the said bolts L L passed through the ends so that they are outside
the magnetic circuit and do not interfere therewith. The coils P and S are illustrated
as wound one over the other. The iron arranged as above described and the coils are
mounted bodily in the frame F, they rest upon its lower surface and are held firm
thereon by the set screws f¹¹. The frame F is bolted to the bed plate G through
which the leads are passed in the usual way to the terminals TP Ts and the whole is
enclosed by the cover H.
Figures 4, 5 and illustrate another convenient way of mounting the active iron
and coils disposed as specified. In this case the bed plate G is made hollow and has
its two ends g g extended vertically upwards and provided with short side flanges g' g¹
thus forming a rectangular receptacle for holding together the ends of the horizontal
groups A with the vertical groups B between them.
A bolt is passed through the hollow bed plate G at either end upon which the
lower member A rests, or a flange or rib may be substituted therefor, and the upper
member A is held in position by screwed clamps f¹.
The primary and secondary coils are illustrated as bound with tape t, arranged
alternately, and separated by insulation I, and the whole is enclosed as before by the
cover H which is bolted to a flange on the bed plate G.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, we declare that what we
claim is :-
1. An electric transformer having the active iron parts of the magnetic circuit
composed of a number of thin plates combined together substantially as described and
arranged in combination with the primary and secondary coils substantially as set
forth.
2. An electric transformer having the active iron parts of the magnetic circuit
composed of a number of thin rectangular iron plates placed face to face with paper

page_text: or other insulation between them the whole being. bound or secured together and
combined substantially as described, and arranged longitudinally and transversely so
as to pass through and surround the primary and secondary coils but with or without
ventilation spaces, substantially as set forth.
3. Mounting the active iron parts of the magnetic circuit and the coils of electric
transformers arranged and combined as hereinabove specified and claimed either in
a frame secured to a bed plate as described in reference to figures 1, 2 and 3, or in a
hollow hed plate adapted to form a receptacle as described in reference to figures.4,
5 and 6, and all arranged substantially as and for the purposes described and
illustrated.