Improvements in the Construction of Transformers.
Year: 1887

page_text: Date of Application, 7th Feb., 1887
Complete Left, 7th Nov., 1887
Complete Accepted, 13th Jan., 1888
PROVISIONAL SPECIFICATION.
Improvements in the Construction of Transformers.
We GISBERT KAPP, of 22 Wellington Street, Strand, London in the county of
Middlesex, WILLIAM HENRY SNELL, of "Lamorna" Oxford Road, Putney, in the
county of Surrey, and JULIAN MONEY VERNON KENT, of Connaught Mansions,
Westminster in the county of Middlesex, Electrical Engineers do hereby declare the
nature of this invention to be as follows:-
This invention relates to certain improvements in the construction of transformers
and has for its object to produce a simple and inexpensive type of apparatus having
a high electrical efficiency and adapted for self regulation when used in parallel
circuit or with certain slight modifications hereinafter set forth when used in series.
The apparatus may be constructed according to various modified forms.
According to one arrangement the core is formed of a number of plates of
a U or shape and of suitable size, which may be economically stamped out of thin
hoop or sheet iron so that when any number are placed face to face a trough is
formed. The plates are insulated and upon their upright sides or horizontal base the
coils of insulated wire are placed. Two such troughs may advantageously be placed
side by side separated is desired by distance pieces to provide for efficient ventilation,
thus forming a double trough and the coils would then be placed over the adjacent
sides of the troughs. These coils in which the primary and secondary currents
circulate may be separately wound and placed side by side so as to be readily
detachable. A cover for the trough is also provided formed of separate rectangular
plates adapted to fit upon the top of the trough, and these plates are insulated from
each other and may be wound or provided in the direction of the length of the trough
with a coil which may be detachable as described.
To facilitate self regulation when placed in series the self induction of the secondary
circuit may be reduced by dividing the iron core into sections and providing each
one of such sections with a separate secondary coil each connected to its own separate
working circuit, or these coils may be joined electrically in parallel. To increase the
surfaces of contact between the cover and the trough, the upper extremities of the
vertical sides of the trough may be obliquely bevelled off internally and the cover
made of a trapezoidal shape to fit.

page_text: In some cases we make the sides of the trough longer than the space occupied by
the coils and construct the cover so as to pass freely down into the trough. We may
also taper the sides of the trough towards the top and by these means we can vary the
magnetic effect of our apparatus by varying the depth to which the cover is
inserted.
We may thus regulate the efficiency or effect of the apparatus either by hand or
automatically, or we may utilize the movement of the cover to actuate any suitable
regulating device.
In the latter case the apparatus may be used either with
alternating or with continuous currents.
The apparatus may be provided with a bed plate, terminals, and movable cover.
Dated this Seventh day of February 1887.
J. C. CHAPMAN,
70, Chancery Lane, W.C.,
Agent for Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in the Construction of Transformers.
We GISBERT KAPP of 22 Wellington Street Strand, London in the county or
Middlesex, WILLIAM HENRY SNELL of "Lamorna" Oxford Road, Putney, in the
county of Surrey, and JULIAN MONEY VERNON 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 :-
This invention relates to certain improvements in the construction of transformers
and has for its object to produce a simple and inexpensive type of apparatus having a
high electrical efficiency and adapted for self regulation when used in parallel circuit,
or with certain slight modifications hereinafter set forth when used in series. The
apparatus may be constructed according to various modified forms.
The accompanying drawings clearly illustrate our improved construction. Sheet 1
shows diagrammatically the various methods of construction we prefer, and sheet 2
illustrates a transformer constructed in accordance with our invention.
Similar letters of reference refer to similar parts in all of these figures.
According to one arrangement the core is formed of a number of plates a a of the
shape illustrated in figures 1 and 1". The plates are of suitable size and may be
economically stamped out of thin hoop or sheet iron so that when any number are
placed face to face a trough is formed. The plates a a are insulated from each other
by stamped pieces of paper of same shape, or other di-electric placed between them,
the plates are then well and firmly bound round with tape in order that there may be
no chance of their sharp edges cutting the insulation of the copper coils p. s which
are placed upon the upright sides or horizontal base. Two such troughs t t formed
of plates a as specified may advantageously be placed side by side as in figure 2,
separated if desired by distance pieces d d to provide for efficient ventilation thus
forming a double trough and the coils p. s may then be placed over the adjacent sides
of the troughs. If the ventilation space is dispensed with the pair of plates as shown
in figure 2 may be united or stamped out of one piece of metal. These coils p. s in
which the primary and secondary currents circulate may be separately wound on
suitable mandrils and then placed upon the cores side by side or the one over the
other as in figure 3, which is a plan of a trough with its coils, and figure 3 which is
a cross section on line 1-2 of figure 3, so as to be readily detachable.
This arrangement is of considerable advantage in saving trouble where a coil has to
be repaired or renewed. A cover c or armature for the completion of the magnetic
circuit (see figure 5) for the trough or troughs t is also provided formed of separate
rectangular plates placed on edge in the direction of their length so as to fit upon the
top of the trough and these plates are insulated from each other and taped (as
described for the plates a a) and may be wound or provided in the direction of the
length of the trough with a coil p. s which may also lie detachable as described. The

page_text: covers c are not shown in the plans figures 3 and 4. It is obvious that by the use of
these covers the iron is disposed symmetrically with respect to the coils.
To facilitate self regulation when placed in series the self induction of the secondary
circuit may be reduced by dividing the iron core into sections and providing each one
with a separate secondary coil s. This arrangement is illustrated in figure 4
wherein represent three such sections each wound with its coils the primary
coils p being wound over all the coils sss. The coils ss may be each connected with
its own separate working circuit, or may be joined electrically in parallel.
To increase the surfaces of contact between the covers c and the trought the upper
extremities of the vertical sides of the trough may be obliquely bevelled off internally
as indicated in figures 1 1ª and 3ª by dotted lines and the cover made of a trapezoidal
shape to fit. The joining surfaces of the cover and trough should in every case be
planed or trued so as to secure as good a contact as possible.
In some cases we make the upright sides of the trough longer than the space
occupied by the coils p. s and construct the covers so as to pass freely down into the
trough. This modification is shown in figure 6. We may also taper the sides
towards the top and by these means we can vary the magnetic effect of our apparatus
by varying the depth to which the cover is inserted.
In sheet 2 we have illustrated a transformer constructed in accordance with our
invention.
In figure 7 the part marked A is a plan of bed plate. B is a plan of top with
terminal plate removed and C is a horizontal section on line 3-4 of figure 9.
Figure 8 is an end elevation partly in section with coils and bolts removed and
figure 9 is on the left hand side a half front elevation with coils removed, and on the
right hand side a section on line 5-6 of figure 7. The parts above described are
marked with similar reference letters. e is the bed plate and a top plate with
lugs e respectively for holding the troughs t in position, the two parts e and f
being firmly bolted together by the bolts g. h is a base plate of slate or suitable
material for the terminals etc.
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 cores composed of a number of thin metal
pieces combined together substantially as described, and arranged in combination
with the surrounding primary and secondary coils substantially as described.
2.) An electric transformer having the cores for the coils composed of a number of
thin metal pieces, combined substantially as described and shaped and arranged so
that the core forms a trough of double section as indicated in figure 2, but with or
without a ventilation space.
3.) A core for an electrical transformer composed of a number of U shaped plates
stamped out of sheet metal and placed face to face with paper or other insulating
medium between the plates, the whole being bound or secured together and the
magnetic circuit being completed by an armature of similar construction as indicated
in figure 5 substantially as described, and also the specific modifications thereof
indicated by figures 1, 1ª and 6.
4.) The improved electrical transformer herein-before described and illustrated.
Dated this Saranth love of Nabo 1007
J. C. CHAPMAN,
70, Chancery Lane, W.C.,
Agent for Applicants.