Improvements in Electrical Transformers.
Year: 1891

page_text: Date of Application, 25th June, 1891
Complete Specification Left, 25th Mar., 1892-Accepted, 30th Apr., 1892
[Communicated from abroad by ERNEST PRESCHLIN, of Schlabern, Germany,
Electrician.]
Improvements in Electrical Transformers.
WOODHOUSE & RAWSON UNITED LIMITED, of SS Queen Victoria Street,
London E.C. Electrical Engineers and Contractors do hereby declare the nature
of this invention to be as follows:-
The object of this invention is to effect a cheaper and more efficient method for
the manufacture of transformers.
"
To this end we take iron sheets of rectangular shape, in which we form in any
convenient manner two rectangular holes parallel to one another, thus leaving an
intermediate piece, which will form part of the yoke of the transformer. We
next punch or cut out in any convenient manner, these said intermediate yoke
pieces in such a way that each succeeding piece is slightly larger in one direction
than the one before it. We now take these pieces of iron from which the yoke
pieces have been removed, and pile them successively as stamped, one on the top
of the other, with intervening sheets of paper or other suitable material, forming a
prismatic hollow body having a tapering groove at each end of the hollow, then in
the same way we take the yoke pieces, which when piled one on each other, form
a wedge which can be slipped into the above mentioned grooves, or we may stamp
the pieces which together form the yoke of such a form as to allow them to be
tightly wedged into the recess formed by the pieces from which they have been
stamped. Our object being in all cases to obtain a perfect magnetic connection
between the yoke and body of the transformer out of which the yoke has been
formed and to leave recesses in the body of the transformer for the introduction of
the coils which are disposed about. the yoke in such a manner as to allow of their
being easily withdrawn in case of repairs being necessary. A slight withdrawing
of this wedge-shaped yoke can be utilized to vary the electro motive force in the
secondary circuit.
The tapered surfaces of the grooves and wedge may be filed or machined if
necessary. The sheets of the body of the transformer and the yoke are screwed or
rivetted together, the top and bottom plates being made in such a way as to form
a frame work.
On the yoke are slipped the coils forming with it the core of the transformer
and being held in place by two bolts through the top plate of the yoke, thus
securing it to the body of the transformer. The coils may be wound upon a
separate frame of insulating material so shaped as to slip over the outside of the
yoke and be easily removeable. The outside edges of the coil may be protected
by brackets of any non-magnetic metal.
Tffil dar of June 1891

page_text: COMPLETE SPECIFICATION.
Improvements in Electrical Transformers.
We, WOODHOUSE AND RAWSON UNITED LIMITED of 88 Queen Victoria
Street, London, E.C. Electrical Engineers and Contractors, 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 object of this invention is to effect a cheaper and more efficient method for
the manufacture of transformers.
To this end we take iron sheets of rectangular shape as in ACDB Fig. I in
which we form in any convenient manner two rectangular holes E F H G and I J L K
parallel to one another, we next cut or punch out in any convenient manner the
intermediate yoke pieces M N PO Fig. I in such a way that each succeeding piece
is slightly larger in one direction than the one before it, the last one for instance
may be of the shape FKH the intermediate layers being of intermediate lengths
as shown dotted in Fig. 1.
We now take these pieces of iron from which the yoke pieces have been removed
and pile them in order of stamping, with intervening sheets of paper or other
suitable material, and bolt them one on the top of the other, thus forming a
prismatic or hollow body having tapering grooves at OP KH and M NIF at cach
end of the hollow or interior portion. Then in the same way we take the yoke
pieces which when piled one on each other in order of stamping, form a stepped
wedge which can be slipped into the above mentioned grooves.
In the case of Figs. TI and V with their respective end elevations Figs. VI
and VII, we punch the holes EF HG and I J L K, the holes in Fig. III being
rectangular but in Fig. V the angles at F1 and H K are slightly obtuse and acute
respectively, we then cut out the pieces M N PO Figs. II and V thus dividing
the plate ACD B into three pieces, the piece M N PO in Fig. III is T-shaped as
shown, we again, as described in Fig. I, take the pieces of iron and pile and bolt
them together, but not necessarily in the order of stamping, only in this case the
outside pieces A MOB and NCDP are bolted to two castings or thick sheets of
the size A C D B but having no holes in them, which keep. them the necessary
distance apart to allow of the yoke picce fitting tightly, when slipped into the
recess thus formed. Our object being in all cases to obtain a perfect magnetic
connection between the yoke and the body of the transformer out of which the
yoke has been formed, and to leave recesses in the body of the transformer for the
introduction of the coils which are disposed about the yoke in such a manner as
to allow of their being easily withdrawn in case of repairs being necessary.
is obvious from Fig. VII which is a section (with coils in position) of the
construction explained in reference to Fig. I the coils occupying three divisions,
marked SC for secondary circuit, and PC for primary circuit. The bolts or
rivets are shown in section and by detaching or lifting out the yoke with the
bobbins thereon, they can be readily withdrawn from the yoke when clear of the
main body of the transformer. In Fig. VII is given a view looking down on
the bobbins, and from this it may be readily seen that if the yoke and bobbins
are drawn out, say in the direction of the arrow the bobbins can be readily
removed from the yoke. Q in Figs. VII and VII is a casting to form a
framework.
This
Similar letters on Figs. VII and VIII refer to similar parts to those on Fig. I.
In Fig. IX is shown a half elevation half section of a transformer made in
accordance with the construction explained in reference to Figs. III and V, similar
letters here refer to similar parts explained in regard to the first described type.
Fig. X is an end elevation and Fig. XI a plan of the same instrument, and it
will be readily understood that by lifting the yoke by its handle Zit can be
withdrawn from the taper bed when the bolts X and Y are withdrawn, which bind

page_text: t to the outside frame. This handle Z, may be formed out of a thick plate or of
several plates of a suitable shape. The coils or bobbins in this case are not
lifted with the yoke, but the yoke forms as it were a key to hold them in position,
but are drawn out separately after the withdrawal of the yoke.
A slight withdrawing of the wedge shaped yoke can be utilized to vary the
electro-motive-force in the secondary circuit.
The tapered surfaces of the grooves and yoke may be filed or machined if
The sheets of the body of the transformer
necessary to obtain a better contact.
and the yoke are screwed or rivetted together the top and bottom plates being made
in such a way as to form a frame work, or two separate castings R and T Figs. X
and X1 may be used as illustrated. On the yoke are slipped the coils, forming
with it the core of the transformer, and are held in place by bolts X and Y
through the top plate of the yoke, thus securing it to the body of the transformer..
The coils may be wound upon a separate frame of insulating material so shaped as
to slip over the outside of the yoke and be easily removable, the outside edges of
the coil may be protected by brackets of any non-magnetic metal or other suitable
material.
The ends of the coils may be led up to switches disposed in any suitable
manner, and the whole apparatus may be enclosed in a case suitably designed to
comply with the regulations regarding these instruments.
Having now particularly described and ascertained the nature of my said.
invention and in what manner the same is to be performed, I declare that what [
claim is
-
I. In an electrical transformer the manufacture of the sheets which form
respectively the body and yoke of the transformer from single sheets by any
manner and of such a form that when joined
suitable method, but in such a
together they may respectively present hollow wedge and wedge shaped surfaces
having identical angles, substantially as described and for the purposes set forth.
11. In an electrical transformer the combination of a laminated body and yoke
presenting respectively hollow wedge and wedge shaped surfaces having identical
angles with primary and secondary coils suitably disposed about the latter and
within suitably arranged interstices in the former, substantially as described and
for the purposes set forth.
111. The construction of an electrical transformer substantially as described and
5 illustrated in the accompanying drawings.
azıl dave of March 1892.
WOODHOUSE & RAWSON UNITED, LIMITED,
A. L. Foley, Secretary.