US2671196A - Welding transformer - Google Patents

Description

March 2, 1954 F. C. OWEN WELDING TRANSFORMER 3 Sheets-Sheet l Filed June 24, 1948 ATTD RN EY March 2, 1954 F. c. OWEN WELDING TRANSFORMER 3 Sheets-Shem 2 Filed June 24, 1948 ATTU R N EY March 2, 1954 F. c. OWEN WELDING TRANSFORMER 3 Sheets-Sheet 3 Filed June 24, 1948 76 mud M w I N \"IIN TOR fiw/erzEW C. 0 We 72 73 Lmww- Patented Mar. 2, 1954 UNITED STAT OFFICE 2,671,196 WELDING TRANSFORMER Frederick C; Owen, Fayetteville, N. C.

Application June 24, 1948, Serial No. 34,911

8 Claims. 1

"The object of the invention is tov provide a welding transformer in which a capacity is incorporated, not only to correct a relatively'poor power factor, but to generate oscillating currents by which the welding arc is materially improved; to provide a transformer of the oscillating and power factor correction type wherein the capacity is instantly rendered inactive automatically when the secondary or work current is opened, thereby avoiding not only the monetary loss that would otherwise result from capacity charging currents during periods of idleness, but also reducing to a minimum the open circuit voltage, so that thehazard of serious shocks to the operator will be eliminated; to provide a mechanism of'the kind indicated in which the unit weight per unit output isin the range of one pound per-ampere for the maximumcutput in amperes; to provide a transiorrner for the purposespeciiied wherein the primary absorption in amperes will not be excessive even when the secondary is subjected'to short-circuit; to provide a welding transformer having a plurality of magnetic circuits whose coupling is variable in infinitesimal increments and decrements; and generally to provide an alternating current are welder which, for the character of work which it may perform, is. comparatively cheap 'to manufacture and which is of such sturdy form that failure under most exacting conditions. is highly improbable.

'With this object inview, the invention consists. in aeonstruction and .combinationof. parts in which preferred embodiments are illustrated in the accompanying drawings, in which:

Figure l is a side elevational view ofthe single unitiorm of the invention'withthe cover or case removed Figure 2 is a tcpjplan view of the structure of with the magnetic inserts in flux shunt-f ing. position;

Figure 3-is a view similar to Figure? but with the magnetic inserts withdrawm.

l igure t is a sectional view on the-plane indicated by the line l l of Figure 5;

Figure 5 is a sectional view on the plane indicated by the line 55 oiliigure 2;

Figure 6 is'a perspective view of the magnetic inse1 s or shunts and their supporting and optransformer used in the dual form of the inven tion, this having the leakage flux shield;

Figure 8 is an elevaticnal View of the power transformer with the leakage flux shieldv attech 'ure'u is a central horizontal sectional view 2 of. the magnetic inserts and their connected crosshead;

Figure 10 is a diagrammatic View of one form of the single unit style of the invention; 7

Figure 11 is a similar view of another form of the single unit style of the invention; and

Figure 12 is a similar view of the dual unit form of the invention.

The invent on is susceptible of embodiment in separate machines to be used conjointly, or in one machine of either single unit or double unit form. Since a single machine is the most compact and since the dual unit and single unit are substantially identical structurally, the latter has been selected for illustration of the structural details.

In this form the core 20 which is of the shelltype, carries the windings W-! and W-Z on the center leg thereof, these windings being axially and maintained in such spaced relation the spacer plates 2! which span the core transversely (at right angles to the center leg) on epposite'faoes thereof, the spacer plates being tied together by bolts 22 which are preferably of non-magnetic material, the spacer plates being non-conducting material, as, for example, fiber.

Being mounted on the same leg, the windings W-i and W-Z have a common magnetic circuit are therefore more or less closely coupled. Since the effective operation of the invention depends on changing'this coupled relation, means have been provided for doing so without physical change in the relative'positions of the windings. These means consist of magnetic inserts which are movable into and out of position between the windings and are so dimensioned that they span the distances between the center leg and the sides of the core. When in position between the center leg and sides of the core, they serve to divert the fluxes from the two windings back,

through those'sections of the core on which the windings are located. In other words, they divide the magnetic circuit in two, so that each winding has substantially its own magnetic circuit when the inserts are in position. This of course does not mean that there is actually no flux from one winding entering the magnetic circuit of the other, but to all practical purposes that is the case in full shunting positions of the inserts. Of course the extent to which they are inserted determines the degree to which the two magnetic circuits are separated or isolated.

The core is of laminar construction, as is conventional, and the laminae are held together by clamp hars'Zi arranged in pairs at the top and bottom'of the core, the units of each pair being on opposite faces of the core, and the two pairs being held in clamped position by the tiebolts which, however, extend far enough beyond the nuts 24 to receive the strut bars 25 which are vertically arranged, but which the nuts 24 space from the faces of the core, the strut bars crossing the spacer plates 2|. The second nuts of course secure the strut bars in position and these latter act as a supporting means for the elements by which the inserts are supported and actuated. The strut bars on the rear are spanned by yoke 26, welded or otherwise secured to the strut bars. The strut bars on the front carry each a yoke 21, the two yokes 2'| lying in vertical planes while the yoke 26 lies in a horizontal plane. To the cross pieces of the yokes 21, there is secured a plate 28, preferably of insulating material, centrally in which is a bearing 29 in which the journal portion of a screw 30 is rotatively mounted, this journal portion extending far enough out from the plate to receive a crank 3| by which the screw may be rotated. The screw is threadingly engaged with a cross head 32, both it and the cross head being of nonmagnetic material. The cross head acts to unite the two inserts, each of which comprises a laminated section 34, a filler section 35, and a spacer section 33, the laminated section being of the same material as the core 28, the filler section being certainly nonmagnetic and preferably nonconducting as, for example, fiber, and the spacer section being preferably of the same material as the filler section. The three sections of the insert are assembled by tie-bolts 33 of non-magnetic material passing through them and through cross head 32.

The inserts are mounted to move on slides 31 which are terminally connected with the plate 23 and with the cross bar of the yoke 26, being insulated from the latter by a block 38 of insulating material. It is essential to effect this insulation since otherwise eddy currents might be generated in the slides, in View of the fact that they are with n the inductive range of the windings. The slides are non-magnetic but nevertheless are of conductive material.

Obviously rotating the crank 38 will effect.

axial movement of the inserts. The screw, while mounted for angular movement is precluded from axial movement, and, must, therefore impart axial movement to the inserts since they are connected to the cross head with which they are threadingly engaged.

The core is supported on an open frame 39 made transportable by means of the casters 40 positioned one at each corner. A frame 4| coterminus with the frame 39 is supported. by the core at its upper end, the clamp bars in each instance providing the connections between the frame and the core and being welded or otherwise secured to the frame.

The bank of condensers 42 employed for power factor correction and the generation of oscillat ng currents is carried on the frame 39 below the yoke 26.

The spacer plates 2| have clearance openings therein for the passage of the inserts and the spacer sections 33 of the latter are of the same thickness as these spacer plates, so that when the cross head abuts the plates, the magnetic sections of the inserts are in full bridging relation to the center and side legs of the core.

The filler sections are essential to prevent chattering or vibration when the inserts are withdrawn, These filler sections fill the spaces previously occupied by the magnetic sections and yet leave the magnetic circuits unaffected. They fit the spaces snugly enough to prevent vibraticn of the magnetic sections when withdrawn as would otherwise be the case.

In some forms of the invention, the winding W-i will consist of a primary and a closely coupled secondary together with a small winding designed to effect the operation of the circuit closer; and the winding W-Z will consist of a reactance and a companion winding to the circuit closer actuating means.

In another form of the invention, the winding W-Z will include in addition to the reactance, the circuit closer actuating winding and an additional winding whose purpose is to introduce oscillations into the circuit.

In the dual form of the invention, there will be two transformer cores, one surmounting the other, with one core carrying below the spacer plates 2| the primary and above them the secondary. The upper transformer will include a series transformer whose function is to introduce a capacity into the welding circuit.

These various forms are graphically illustrated in the drawings.

One form of the invent on is illustrated graphically in Figure 10, In this form the lower winding is composed of a primary 43 and a closely coupled secondary 44 wound directly over it. There is also incorporatedin this winding a coil 55. The upper co l is composed of a reactance 46 and a coil 41, complemental to the coil 45. The secondary 44 and reactance 46 are in series with each other and with the welding leads 48 and 49. The coils 45 and 41 are serially connected but differentially, that is, differentially physically but electrically cumulatively. Thus the coil 41 is sometimes energized by the flux due to the winding 46 and at other times from the flux due to the coil 43. Also serially included in the circuit with the coils 45 and 41 is the magnetic actuator 5c of the circuit closer 5| which, when it bridges the spaced contacts connects the capacity 42 or bank of condensers across the line 52, one side of which is connected to one terminal of the primary 43 by the conductor 53 and to one side of the condenser by the conductor 54, and the'other side of which is connected to the opposite terminal of the primary by the conductor 55, the opposite terminal of the capacity 42 being connected to the remote terminal of the circuit closer by conductor 56.

When the power switch 51 is closed, the primary is immediately placed across the circuit,

current, at a certain instant, flowing over the conductor 53 through the winding 43, the conductor 55 back to the opposite side of the line. When the primary is energized, it energizes the secondary 44 and also the coil 45. But of course no current flows in the secondary if the latter cir cuit is open, as when the welding electrode is withdrawn from the work. But when there is contact between the electrode and the work, or when a metal weld ng arc is in existence, current will flow through the secondary 44, and the reactance 46, but the phase of this generated current is displaced substantially degrees from the phase of the primary current, which means that the energizing means for the coil 41 is opposite to that of the energizing means for the coil 45. Thus if they are differentially connected, as shown, they will be cumulative in effect on the circuit closer actuating coil 50. Thus when the filcctrode is brought into contact with the work As above stated, the dual form of the invention calls for surmounting the :power transformer with the series or oscillating transformer and except for this variation, the structure is otherwise like that disclosed in Figure 1.

Some designs of transformers call for flux leakage and in cases of that character involving the present invention, the core is shielded with a ring 90 of laminar construction similar to that of the core but of much less cross sectional area than the core. The ring is spaced from the core by insulating spacers 9i and is secured to the core by clamp plates 92 positioned at such points as may be necessary to hold the ring in place, the flux leakage passing around this ring, and therefore not affecting any metal case or housing which encloses the whole mechanism over the frames 39 and ll.

The invention having been described, what is claimed as new and useful is:

1. An alternating current are welder comprising a shell-type core, primary and secondary windings on the center leg of said core with at least part of the latter axially spaced from the former, and magnetic inserts dimensioned to span the distances between center and side legs of the core and movable into and out of positions between the spaced windings on the said center leg, and a resonant circuit reactive on said windings and having its resonant frequency dependent on the setting of said inserts.

2. An alternating current are welder comprising a shell-type core, primary and secondary windings on the center leg of said core with at least part of the latter axially spaced from the former, and magnetic inserts dimensioned to span the distances between center and side legs of the core and movable into and out of positions between the spaced windings on the said center leg, and a resonant circuit reactive on said windings and having its resonant frequency dependcut on the setting of said inserts, said inserts being adjustable in infinitesimal increments and decrements.

3. An alternating current are welder comprising a shell-type core, a plurality of windings on the center leg of said core with one axially spaced from the others and constituting an impedance, one of said windings being energized from an alternating current source, a resonant circuit rendered active by another of said windings, and magnetic inserts dimensioned to span the distances between the center and side legs of the core, and movable into and out of positions be tween the impedance and the other windings.

4. An alternating current arc welder comprising a shell-type core, a plurality of windings on the centerleg of said core with one axially spaced from the others and constituting an impedance, one'of-said windings being energized from an alternating current source, a resonant circuit rendered active by another of said windings, magnetic inserts dimensioned to span the distances between the center and side legs of the core, and movable into and out of positions between the impedance and the other windings, and means 1 to adjust the inserts in infinitesimal increments and decrements.

5. An alternating current arc welder comprising a shell-type core, a plurality of windings on the center leg of said core with one axially spaced from the others and constiuting an impedance, one of said windings beingjenergized from an alternating current source, a resonant circuit rendered active by another of said windings, magnetic inserts dimensioned to span the distance between the center and side legs oi! the core, and movable into and out of positions between the impedance and the other windings, and means to adjust the inserts in infinitesimal increments and decrements, and comprising a non-magnetic crosshead to which the inserts are connected and a crank-actuated non-magnetic screw having a rotary mounting on the core and a threaded mounting in the cross head.

6. An alternating current arc welder comprising a shell-type core, a plurality of windings on the center leg of said core with one axially spaced from the others and constituting an inductance, one of said winding being energizing from an alternating current source, a resonant circuit rendered active by another of said windings, inserts cross-sectionally dimensioned to span the spaces between the center leg and the side legs and including each a, filler section and a laminated section of which the latter is magnetic and the former non-magnetic, parallel guides carrying the inserts and disposed in a plane at right angles to the center leg and between the inductance and the other windings, and manual means for advancing and retracting the inserts to position them where either the laminated sections or the filler sections span the spaces be:- tween the center leg and the side le s or where such spaces are spanned in part by the laminated sections and in part by the filler sections.

7. An alternating current are welder comprising a core, primary and secondary windings close 1y coupled and positioned at one point on the core, an additional winding in series with the secondary winding and positioned at a remote point on the core, a resonant circuit and a switchcon trolling its inclusion in circuit with one of the aforesaid windings, magnetic operating means for said switch, and means for energizing the magnetic means, said energizing being actuated jointly by the primary winding and the additional winding to effect closing of the switch and by the primary winding alone to effect opening of the switch.

8. An alternating current are welder comprising a core, primary and secondary windings closely coupled and positioned at one point on the core, an additional winding in series with the secondary winding and positioned at a remote point on the core, a resonant circuit and a switch controlling its inclusion in circuit with one of the aforesaid windings, magnetic operating for said switch, and means for energizing the mag-. netic means and comprising a pair of windings of which one is closely coupled to the primary winding and the other similarly coupled to the additional winding, the said pair of v windings being differentially connectedin series with each otherand in serieswith the magneticv operating means. V. a

FREDERICK .C. OWEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 851,743 Gehrkens Apr. 30, 1907 1,305,361 Holslag June 3, 1919 1,665,869 Weed Apr. 10, 1928 1,876,427 Lennox Sept. 6, 1932 2,027,593 Howard Jan. 14, 1936 2,091,366 Klinkhamer Aug, 31,. 1937 2,136,863 Owen 'No v'. 15.1938 2,364,881 Tyrner Dec. 12, 1944 2,441,814 '1 Hang May 18, 1948

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