U.S. patent number 3,697,912 [Application Number 05/870,364] was granted by the patent office on 1972-10-10 for welding transformers.
Invention is credited to Arne Solli.
United States Patent |
3,697,912 |
Solli |
October 10, 1972 |
WELDING TRANSFORMERS
Abstract
The present invention relates to a welding transformer, of the
kind in which each of the coils of the primary and secondary
circuits is divided into two parts extending parallel to a magnetic
shunt member and so arranged on the two transformer legs that the
two coil parts of the primary coil are located on the one side of
the shunt member and the two coil parts of the secondary coil on
the other side, and wherein the amperage is controlled by means of
the substantially M-shaped shunt member, which is displaceably
arranged between the primary circuit and the secondary circuit.
Inventors: |
Solli; Arne (Porsgrunn,
NO) |
Family
ID: |
27181691 |
Appl.
No.: |
05/870,364 |
Filed: |
September 12, 1969 |
Current U.S.
Class: |
336/133 |
Current CPC
Class: |
H01F
27/263 (20130101); H01F 29/10 (20130101) |
Current International
Class: |
H01F
27/26 (20060101); H01F 29/10 (20060101); H01F
29/00 (20060101); H01f 021/06 () |
Field of
Search: |
;336/130,132,133 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kozma; Thomas J.
Claims
What is claimed is:
1. Welding transformer, in which the coils (2,3) of the primary and
the secondary circuits each is divided into two parts extending
parallel to a magnetic shunt member (4) and so arranged on the two
transformer legs that the two coil parts (2,2) of the primary coil
are located on the one side of the shunt member (4) and the two
coil parts (3,3) of the secondary coil on the other side, and
wherein the amperage is controlled by means of the substantially
M-shaped shunt member (4), which is displaceably arranged between
the primary circuit and the secondary circuit, characterized in
that the ratio of the width of the center leg of the magnetic shunt
member (4) to that of the outer leg of the same is approximately as
2 to 1, and that the ratio of the widths of the outer legs is
approximately as 1 to 1, and that the ratio of the length of the
window of the transformer core (1) in the longitudinal direction of
the shunt member to width of the legs of the core is approximately
as 2 to 1, so that the center leg of the magnetic shunt member,
together with the primary and secondary coil parts (2,2; 3,3) fill
out the window of the core (1), while the outer leg and the yoke of
the shunt member (4) fill out the remaining outer space between the
primary and secondary coil parts when the shunt member (4) is in
its inserted position.
2. Welding transformer according to claim 1, characterized in that
the legs of the M-shaped shunt member (4) at their end portions are
so shaped in relation to the circumference of the primary and
secondary coils (2,3) that substantially all points of the end
surfaces (18, 19,20) of said legs, when the shunt member is moved
out of or into the intermediate space of said coils, approximately
simultaneously pass the outer limits of said intermediate
space.
3. Welding transformer according to claim 1 characterized in that
grooves (5) are formed in the side surfaces of the center leg of
the magnetic shunt member (4), said grooves (5) being formed by
selecting a smaller width of some of the shunt member plates than
for the remaining plates, and that these grooves (5) correspond to
or cooperate with guide members (6) provided on the inner side
surfaces of the transformer legs, and that the plates forming the
side walls (7) of the groove (5) are bent inwards towards each
other, in order to rest resiliently against the guide members
(6).
4. Welding transformer according to claim 1 characterized in that a
guide device for the shunt member (4) comprises guide grooves
provided on the shunt member (4) and guide arms (13) provided on
the core (1), said guide arms (13) forming a part of a clamp device
for compression of the core plates.
5. Welding transformer according to claim 4, characterized in that
said clamp device comprises a first clamping piece (25) having
holes for insertion of bolts (8,9) fixedly or detachably mounted on
a second clamping piece (26), one (9) of said bolts (8,9) being
extended beyond said second clamping piece (26), said bolt
extension forming said guide arm (13).
6. Welding transformer according to claim 5, characterized in that
the clamping pieces (25,26) have outwardly projecting flanges,
acting as distance pieces for the coils (2,3).
7. Welding transformer according to claim 6, characterized in that
the extended bolt (9) has a projection or gradation provided with a
pin (11) for engaging one end of said second clamping piece (26),
said extended bolt (9) and said other bolt (8) being inserted into
the holes of the first clamping piece (25), in order to compress
the core plates and simultaneously providing a fastening for the
guide arm (13).
8. Welding transformer according to claim 7, characterized in that
said guide arms (13) at their free ends are supported relative to
each other by means of a yoke (15), on which a rotatable spindle
(16) is provided, said spindle cooperating with a nut (17), mounted
on the side surface of said shunt member (4) and being adapted to
move said shunt member out of or into the intermediate space of the
primary and secondary coils, when said spindle is rotated.
Description
In connection with welding transformers it has been previously
known to control the welding current by means of an additional
dissipation (dispersion) field.
In connection with such welding transformers it is most convenient
when the welding current can be controlled (regulated) over a large
range (area); that the transformers are small in size and
light-weighted for transport, etc.
These objects are obtained according to the invention by provision
of a welding transformer of the kind described being characterized
in that the ratio of the width of the center leg of the magnetic
shunt member to that of the outer legs of the same is approximately
as 1 to 1, and that the length of the window of the transformer
core in the longitudinal direction of the shunt member to the width
of the legs of the core is approximately as 2 to 1, so that the
center leg of the magnetic shunt member, together with the primary
and secondary coil parts fill out the window of the core, while the
outer leg and yoke of the shunt member fill out the remaining outer
space between the primary and secondary coil parts when the shunt
member is in its inserted position.
A maximum welding current is then more rapidly obtained in the
adjustment range for the shunt in which the shunt is moved out of
the intermediate space and passes the outer limit of the coils.
According to the invention the legs of the M-shaped shunt member
are so shaped at their end portions that substantially all points
of said end surfaces simultaneously pass the outer limits of said
intermediate space.
The end surfaces of the shunt member legs are shaped to correspond
to the outer circumference of the coils. This is achieved by
removing the inner corners of the outer legs of the M-shaped shunt
member and also both corners of the center leg, whereby the shunt
member obtains concave surfaces substantially corresponding to the
outer circumference of the coils.
The large area of the shunt member allows a correspondingly lesser
width (approximately one-third of that of conventional welding
transformers) so that the primary and secondary coils approach each
other to a very high degree, and a substantially higher maximum
welding current is obtained.
In order to obtain a simple and vibrationless guiding of the shunt
member some of the shunt member plates are narrower than the other
plates, thus forming grooves in the center leg of the shunt member,
said grooves engaging guide members provided on the inner sides of
the transformer core. Those plates forming the side walls of said
grooves are bent inwards towards each other, so that they rest
resiliently against said guide members. Movement of the shunt
member is obtained by means of a spindle cooperating with a nut
mounted on the side surface of the shunt member. This method of
guiding the shunt member requires very little space and it is
therefore not necessary to remove too much of the plate material of
the shunt member in order to procure space for the guide arms. Said
guide arms are fastened to the transformer core and engage grooves
provided in the shunt member. Said guide arms are fastened to the
core by means of a clamp device, which simultaneously serves to
compress the plates of the transformer core. The guide arm is
formed with a step with a pin cooperating with one end of a
clamping piece, to the other end of which a bolt is fixedly or
detachably mounted, said bolt being inserted into another clamping
piece on the other side of the transformer core. These clamping
pieces are compressed around the transformer core by means of nuts
on said bolt's end portions. The outer ends of the guide arms are
supported relative to each other by means of a yoke, on which a
rotatable spindle is provided, said spindle cooperating with a nut
member on the shunt member. By rotation of the spindle the shunt is
moved out of or into the intermediate space of the primary and
secondary coils.
Other objects, features and details of the welding transformer
according to the invention will become apparent from the following
description taken in conjunction with an embodiment.
In the drawings:
FIG. 1 shows the transformer in side elevation, illustrating the
magnetic shunt member, the coils and guiding devices.
FIG. 2 shows the transformer in plan view.
FIG. 3 is a perspective view of a guiding provided in the
transformer core cooperating with a groove provided in the magnetic
shunt member.
FIG. 4 is an exploded perspective view of the clamping device.
The welding transformer comprises a rectangular core 1 having
divided primary and secondary coils 2 and 3, an intermediate
M-shaped magnetic shunt member 4, the center leg of which, together
with the coils 2 and 3, fill out the transformer core window. When
the magnetic shunt member occupies its inner (lower) position, its
outer leg and yoke will fill out a substantial part of the air
space between the coils 2,3 of the primary and secondary
circuits.
By correct measurement of the coil parts, the core 1 and the
magnetic shunt member 4, in order to obtain an optimally compacted
(concentrated) construction of the transformer, the coils 2,2 and
3,3 will be wound in such a manner that approximately full (total)
utilization of the available area of the window of the transformer
is achieved (excepting the space occupied by the shunt member).
Thereby, a certain ratio is established between the width of the
center leg and that of the outer leg, said ratio being
approximately 2:1. The end surfaces 18, 19,20 of the M-shaped shunt
member 4 are shaped in accordance with FIG. 1, so that when the
shunt member 4 is moved out of the intermediate space of the
primary and secondary coils 2 and 3, substantially all points of
said end surfaces will pass the outer limit of said coils
simultaneously. The shunt member 4 will thereby leave the magnetic
fields of the coils, whereby a maximum amperage is more rapidly
obtained.
In order to provide a simple and vibrationless guiding between the
transformer core 1 and the magnetic shunt member 4, the center
plates of the center leg of the latter may be narrower than the
other (see FIG. 3), so that grooves 5 are formed, such grooves 5
engaging guide members 6, provided on the inner portion of the
core. Those plates forming the side walls 7 of the groove 5, are
bent somewhat inwards towards each other, so that a resilient
connection between the guide member 6 and the groove 5 is obtained.
FIGS. 1 and 4 illustrate a guiding device between the core 1 and
the magnetic shunt member 4, said device comprising clamping means
compressing the plates of the core. The clamp device comprises a
first clamping piece 25 and a second clamping piece 26,both having
a U-shaped section and adapted to compress the plates of the core 1
by means of bolts 8 and 9. One (8) of said bolts 8,9 is fixedly
(rigidly) connected with the clamping piece 26 and the other
detachably connected with the clamping piece 26 by means of a pin
11 projecting from a step 10 adapted to engage a hole 12 in the
clamping piece 26. A guide arm 13 is at its free end supported
relative to another guide arm 13 by means of a yoke 15. On said
yoke 15 a rotatable spindle 16 is provided, said spindle engaging a
nut member 17 provided on the side surface of the shunt member 4.
By turning the spindle 16 the shunt member 4 is moved into or out
of the intermediate space between the primary and secondary
coils.
The flanges of the clamping pieces 25, 26 serve as distance pieces
for the coil parts 2,3.
According to the invention, transformers of the kind described
become smaller in size and weight than ordinary welding
transformers possessing the same maximum amperage. According to the
invention a lower amperage is obtainable as compared with
conventional transformers of this kind.
* * * * *