Improvements in Electrical Transformers.
Year: 1894

page_text: Date of Application. 29th May, 1894
Complete Specification Left. 28th Feb. 1895-Accepted, 6th Apr., 1895
Improvements in Electrical Transformers.
I, JOHN AUGUSTINE KINGDON of 29 Marlborough Hill, St. John's Wood in the
County of London, Electrical Engineer do hereby declare the nature of this
invention to be as follows:-
I construct the cores of a transformer for alternating currents of thin iron or
steel plates of a rectangular shape, having a rectangular opening stamped near their
centres so as to resemble to some extent the letter O. I employ two piles of these
plates placed side by side. The windings of the primary and secondary coils pass
up through the opening in one pile of plates, and down through the opening in the
other pile of plates. The coils are wound separately and one of the ends of each
plate is cut across so that the plate may be slipped into its position. The width of
the opening of the coils is slightly greater than double the width of the sides of the
plates which form the core, and which are placed within the coils. The distance of
the cut in the plates from the outer edge of the core side, is slightly less than the
width of the opening in the coils. The plates are placed in position with the cuts
alternately at the one end of the pile and the other. The width of the ends of the
plates may be greater than the width of those sides which are within the coils.
This arrangement reduces the magnetic reluctance at the cut to a small quantity.
The plates are clamped between suitable frames, and the coils are insulated from
them in any suitable manner. The sectional area of the shell may be greater than
An air space may
the sectional area of the core, so as to reduce the hysteresis loss.
be left between the two piles of plates.
1001
Improvements in Electrical
I, JOHN AUGUSTINE KINGDON of 29 Marlborough Hill, St. John's Wood in the
County of London, Electrical 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 :-
I construct the cores of a transformer for alternating currents of thin iron or steel
plates of a rectangular shape, having a rectangular opening stamped near their
centres so as to resemble to some extent the letter O. I employ two piles of these
plates placed side by side. The windings of the primary and secondary coils pass
up through the opening in one pile of plates and down through the opening in the
other pile of plates. The coils are wound separately, and one of the ends of each
plate is cut across so that the plate may be slipped into its position. The width of
the opening in the coils is slightly greater than double the width of the sides of the
plates which form the core, and which are placed within the coils. The distance
of the cut in the plates from the outer edge of the core side, is slightly less than the
width of the opening in the coils. The plates are placed in position with the cuts
alternately at the one end of the pile aud the other. The width of the ends of the

page_text: plates may be greater than the width, of those sides which are within the coils.
This arrangement reduces the magnetic. reluctance at the cut to a small quantity.
The plates are clamped between suitable frames and the coils are insulated from
them in any suitable manner. The sectional area of the shell may be greater than
the sectional area of the core, so as to reduce the hysteresis loss. An air space may
be left between the two piles of plates.
:
Fig. 1. of the accompanying drawings is a plan of a single plate, C being the cut
across the end and E, E two slots for the insertion of insulating material.
Fig. 2. is a sectional plan of a transformer. A is a plate in one pile of plates and
B a plate in the other pile. P is one of the windings and S is the other winding. In
order to insulate the winding S from the winding P, an insulating plate F placed
between them extending into the slots E E. In order to insulate the. winding. P
from the core plates A and B, insulating plates G G are bent round the outsides of
the winding P so as to extend into the slots E E.
Fig. 3. is an elevation of a transformer showing the piles of plates A and B and
the windings P and S.
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 :-
A transformer, whose.core.consists of two piles of plates, constructed substantially
as herein before described and illustrated in the accompanying drawings.
Dated this 27th day of February 1895
J. A. KINGDON.