Note: Descriptions are shown in the official language in which they were submitted.
1~771~7 Case 2508
This invention relates to windings for electro-
magnetic induction devices and, more particularly, to electrical
sheet windings for use in transformers.
One of the problems encountered in the design of
transformers is how to dissipate the heat generated in the
sheet winding. The sheet winding is normally employed as
the low voltage winding and is located next to the core of
the transformer. The high voltage winding is generally a
wire wound winding surrounding the low voltage winding.
Because of the compactness of the sheet winding,
care must be taken to ensure that it does not overheat. One
method Gf ensuring adequate cooling of the sheet winding
has been to provide insulated spacers between certain turns of
the sheet winding to produce a space for cooling fluid to
- circulate between the turns and aid in dissipating the heat
produced in the winding. One such type of construction is
shown in Canadian Patent 639,271 dated April 3, 1962 to
J. Church, L. Rabins and R.J. Ringlee.
This type of construction has the disadvantage
that it places some of the turns of the winding further away
from the core. To overcome this problem it is ~nown to split
the sheet winding into two equal parts. That is, the sheet
material is made half the width and is then wound into an
upper portion and a lower portion, around the same core, and
the t~o portions are insulated from one another. The two
portions are then interconnected in series such that they
form a composite sheet, winding with the result that more
turns are produced without going too far from the core, and
the cooling of the winding is enhanced.
One of the problems encountered when the sheet
winding is wound in two portions is how to connect the two
portions to form a single, composite, series winding. In
the prior art this connection has been made in the gap
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occurring between the two portions of the winding. This results
in insulation problems at the gap dur to the interconnection and
results also in a winding structure that is weakened mechanically.
` Hithertofore the composite sheet winding has been described as
having two equal portions. It should be noted, however, that the
composite sheet winding can have two or more equal portions.
i
The present invention is directed to an improved
interconnection between the separate portions of a composite
sheet winding. Briefly stated, the present invention comprises
the interconnection of two or more separate sheet winding portions,
spaced apart along a common axis, into a single composite sheet
winding. The sheet winding portions are insulated from one another
with insulation extending continuously from end to end, and the
start of each portion, as well as the finish of each portion, is
brought out to a common end of the composite winding via insulated
conductors. The insulated conductors are then interconnected,
externally of the composite winding, so as to electrically join
the separate winding portions. Such a construction eliminates
"cross-overs" in the gaps between the winding portions and
: 20 results in a mechanically stronger structure.
Stated in another way, the present invention comprises
a composite sheet winding for an electromagnetic induction
apparatus, the composite sheet winding comprising: two or more
~` sheet winding portions spaced apart along a common axis and
insulated from one another; and insulated conductors connecting
the start and the finish of each sheet winding portion to the
; exterior of the composite winding.
Stated yet another way, the present invention comprises
a low voltage composite sheet winding for an electromagnetic
induction apparatus, the composite sheet spaced apart along
a common axis, insualted from one another and having respective
start and finish ends, each of the first and second sheet winding
portions comprising an elongated sheet of electrically conductive
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-- 2 --
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1~77~47
material spirally wound around a common insulated core; the
core having an axis coincident with the common axis; electrically
insulated conductors extending over portions of the radial
peripheries of the composite winding for connecting the start
and finish ends of the first and second winding portions to
the exterior of the composite sheet winding at a common end
therefor; and said first and said second winding portions connected
in series at the exterior by an interconnection of the electrically
insulated conductor connected to the finish end of the first
winding portion with the electrically insulated conductor
connected to the start end of the second winding portion.
A preferred embodiment of the invention will now be
described with reference to the accompanying drawings in
which:
Figure 1 is a simplified schematic of a prior art
construction; and
Figure 2 is a simplified schematic of a transformer
incorporating the present invention.
Figure 1 depicts a simplified prior art construction
used in transformers. A conventional core 10 is shown surrounded
by a low voltage (LV) composite winding 11 comprised of two
sheet winding portions 12 and 13. Each sheet winding portion
12 and 13 is a comprised of a number of turns 14, of a sheet
conductive material (such as sheet aluminum). Five turns 14
are shown in each of the portions 12 and 13. Located between
the turns 14 are insulators 15 to insulate adjacent turns 14
from one another. An insulated conductor 17 connects the two
winding portions 12 and 13 as shown in the Figure. The two
portions 12 and 13 are connected in a series circuit relationship
in order to provide the composite winding 11 with a larger
number of turns and to keep the turns closer to the core 10
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than they would be ~therwise. While only two portions 12 and
13 have been shown in Figure 1, mc,re portions could also be
; employed in a similar fashion.
A high voltage ~V) wincling 16 is positioned surrounding
the LV winding 11. High voltage winding 16 is a conventional
wire wound winding.
With a construction of the type shown in Figure 1
there is a problem providing proper insulation in the space
between the portions 12 and 13 due to the interconnection
provided by conductor 17. Because the insulators 15 are not
continuous in the space between the portions 12 and 13, winding
- 11 does not have the mechanical strength it would otherwise have.
- Figure 2 depicts, in simplified form, a construction
according to the present invention. A core 20 is shown surrounded
by a composite low voltage (LV) winding 21. Composite winding
21 is comprised of sheet winding portions 22, 23, and 24. Each
winding portion 22, 23 and 24 is comprised of a number of turns
25, of a sheet conductive material (such as sheet aluminum).
" Five turns 25 are shown in each of the portions 22, 23 and 24.
Located between the turns 25, and continuous throughout the
axial length of the composite winding 21, are insulators 26.
Insulators 26 serve to electrically insulate the turns 25 from
one another and also provide electrical insulation between the
sheet winding portions 22, 23 and 24. Because the insulators
26 are continuous throughout the axial length of the composite
winding 21, the mechanical strength of the winding 21 is
enhanced O
As can be seen from Fig. 2, insulated conductors 31
to 36 inclusive are used to provide electrical connections to
the exterior of composite winding 21 where they are then
interconnected as shown to produce a series connection of
winding portions 22, 23 and 24. This leaves two remaining
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conductors 36 and 31 which form terminals 28 and 29, being
respectively, the start and the finish of the composite low
voltage winding 21.
e winding 21 is then surrounded by a high voltage
(HV) winding 30. HV winding 30 is any conventional type of
wire wound winding.
The foregoing has been a description of the preferred
embodiment of the present invention, as envisioned by the
inventor. It is to be understood that the device depicted and
described in this specification is for one specific application
of the invention only, and variations can be made therefrom
depending upon the particular application. Accordingly, the
device described herein should not be considered as a limitation
of the invention in any manner whatsoever, but rather, considered
solely as an example for illustrative purposes.
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