US1364857A - Alternating-current arc-welding system - Google Patents

Description

W. A. HALL. ALTERNATING CURRENT AIIC WELDING SYSTENI.

APPLICATION FILED SEPT. 23| T918.

Patented Jan.. 49 INET...

UNiTED STATES PAT-ENT OFFICE.

WILLIAM A. HALL,

OF YONKERS, NEW YORK, ASSIGNOR OF ONE-HALF T CHARLES H. FLORANDIN', 0F WESTFIELD, NEW JERSEY.

ALTERNATING-CURRENT ARC-WELDING SYSTEM.

n arc systems as referred to above, it is desirable that a comparatively high voltage be impressed upon the electrodes on `open circuit so that a high voltage will exist at the instant of striking the arc. After the arc has been struck and the working current is owing, it is desirable that this Voltage should be reduced. In other words a high starting voltage and a low working voltage upon the electrodes, is desirable. It is further desirable that this regulation in voltage shall be auto-matic and also that it shall be accomplished without the movement of parts. Accordingly attempts have been made to effect these changes 1n voltage on alternating current systems by means of transforming apparatus wherein there was a shifting of the relative positions of the paths ofthe flux and the windings according to the secondary current in the transformer. lIt has been found, however, in all prior devices that the automatic shifting of the flux paths with relation to the transformer windings, has occasioned such confusion in the distribution of the flux, that the power factor has been low.

It is the main obj ect of the present invention to provide apparatus whereby automatic `regulation of the voltage as above indicated by means of transforming apparatus without moving partsand in response to the secondary current is effected but with an improved power factor.

Other and ancillary objects of the invention will appear hereinafter.

In the accompanying drawings which illustrate the invention- Figure 1 is a View of a shell type transformer adapted for use in a system embodying the invention, the transformer core be- Specication of Letters Patent.

Patented Jan. 4, 1921.

Application tiled September 23, 1918. ,Serial No. 255,347.

Fig. 2 is a section on the line 2--2 of' Fig. 1;

Pig. 3 is a diagram of connections of an arc welding s stem including a transformer as shown in *igs. 1 and 2, and embodying the invention, and

Fig. 4 is a view similar to Fig. 2 but showing the 4distribution of iux under different conditions.

Referring to the drawings, the transformer employed, comprises a laminated core 1. Within this core are slots as 2 and 3 and interiorly of the slots 2 and 3 are other slots 4 and 5. In the slots 2 and 3 are placed the primary winding 6 and the secondary winding section 7, while in the slots 4 and 5 are placed another secondary winding section 8 and an adjusting winding 9. It will be seen that the slots 4 and 5 and their contained windings, are symmetrically arranged with relation to the slots 2 and 3 and their contained windings. The windings 6 and 7, it will be observed, embrace the sections 10, 11 and 12 of the core, while the windings 8 and 9 encircle the section 11 only.

The connection of the windings may be best understood by reference to the diagram of connections of Fig. 3. Suitable supply leads 13 and 14 are connected to any suitable source of alternating current. Connected across these leads 13 and 14 is the transformer primary winding 6. The secondary winding section 7 is connected in series with the secondary winding section 8, the terminals of these windings being connected with vthe electrodes 15 and 16 of the arc for acting upon the work. Usually one of these electrodes as 16, is the work itself, while the other as 15 is manipulated by the operator. The adjusting winding 9 is connected across the leads 13 and 14 in series with an adjustable non-inductive resistance 17, whereby the current may be varied in the winding 9.

With the electrodes 15 and 16 separated and with no arc between them, that is, the secondary circuit being open, the flux passing through the interior of the primary coil 6 will pass through the core sections 10, 11 and 12. This will induce electromotive force in the secondary winding or coil7, while that portion of the flux which passes through the core section 11, will thread the interior of the secondary coil 8 and induce a corresponding amount of electromotive force therein. The distribution of flux is as indicated by the lines a of Fig. 2. The secondary windings 7 and 8 being connected in series, these electromotive forces will be added together so that the potential at the terminals of the secondary sections will be the sum of the electromotive forces generated in them. Consequently the voltage impressed upon the electrodes 15 and 16 on open circuit and u on striking the arc, will be the sum of the e ectromotive forces generated in the coils 7 and 8 as above referred to.V

When, however, the archas been struck and current flows in the secondary circuit, thel magnetomotive forces due to the secondary ampere turns, will oppose the magnetomotive forces due to the primary winding, as is well understood. The wlnding section 8 of the secondary is preferably arranged so that at the normal working load of the secondary circuit, the primary magnetomotive forces tending to force flux through the core section 11 will be neutralized by the .magnetomotive forces due to the ampere turns of the secondary winding 8. The flux distribution is then as indicated by the lines b of Fig. 4f. In order that this adjustment of neutrality may be readily brought about where it is impracticable to effect this by the secondary coils alone, the adjusting winding 9 is supplied. The ampere turns of this' winding may be suitable to effect the desired regulation by means of the variable resistance 17 which 'is preferably non-inductive so as to avoid shifting of the phase of current in the winding 9. Where such shifting exists the currents in' the windings 8 and 9 and consequently their magnetomotive forces would be out of step and would not therefore be so Well adapted to the neutralization above referred to. 1

With the magnetomotive forces acting upon the core section .11 neutralized, there will be no flux through this core section, and,

there being no flux threading this core section, substantially no electromotive force will be induced in the secondary coil section 8. The electromotive force impressed on the arc electrode therefore, will be substantially that generated in the secondary winding section 7. It will now be seen that there will be a high electromotive force, that due to the electromotive forces of the windings 7 and 8, impressed upon the electrodes 15 and 16 on open circuit and at the instant the arc is struck, while the voltage impressed on the electrodes while normal working current is flowing will be substantially that generated in the section 7 and is therefore lower than the open circuit or arc starting voltage.

of the electromotive force otherwise generated in the secondary. winding section 8, is effected wlthout producing such a -disturbing influence. upon the relations of the primary winding 6 and the secondary winding section 7, the core sections 10 and 12 prbviding ample paths for the flux when the section 11 is not used as such path. Also since substantially no flux threads lthe section 8, it will have'no self induction and as 1t 1s in series in the secondary circuit this very materially raises the power factor. It is desirable that the winding section 8 be symmetrically arranged with relation to the windings 6 and 7 so that the magnetomotive forces may be balanced. While the invention has been illustrated in what is considered its best embodiment, 1t may have other embodiments without departing from its spirit and is not therefore limited to the structure shown in the drawing.

What I claim isf 1; A shell type transformer having a core, a primary winding and a sectional secondary w1nd1ng, one of said sections being arranged interiorly of the other and encircling different sections of the core.

2. 'A shell type transformer having a core, a primary winding and a sectional secondary wlndlng, one of said sections being arranged interiorly of the other and encircling different sections of the-core, the interiorly arranged secondary section substantially neutralizing the magnetomotive forces acting upon the core section encircled by it.

3. A shell type transformer having a core, a primary winding and a sectional secondary winding, one of said sections being arranged interiorly of the other-and encircling different sections of the core, and auxiliary means for adjusting the magnetomotive forces acting upon the core section encircled by one of the secondary winding sections. l 4. A shell type transformer having a core,

a primary wlnding and a sectional secondary winding, one of said sections being arranged interlorly of the other and encircling different sections of the core, the .interiorly arranged secondary section reducing the flux in the coresection encircled by it, occasioned by the primary magnetomotive force.

5. A shell type transformer having a core, a primary winding and a sectional secondary winding, one of said sections being arranged interiorly of the other and encircling different sections of the core, the interiorly arranged secondary section being symmetrical with relation to the other secondary section.

6. A transformer having a core, a primary Winding and a sectional secondary Winding, the secondary sections encircling different sections of the core, a secondary section substantially neutralizing the primary magnetomotive forces acting upon the core sections encircled by it.

7. A transformer having a core, a primary winding and a sectional secondary winding, the secondary sections encircling different sections of the core, and auxiliary means for adjusting the magnetomotive forces, acting upon a core section encircled by one of the secondary Winding sections.

8. A transformer having a core, a primary Winding and a sectional secondary Winding, the secondary Winding sections being connected in series and encircling different sections of the core, one of said secondary sections at a predetermined load substantially neutralizing the magnetomotive forces acting upon the core section encircled by it.

In testimony whereof I have signed this specication this 17th day of September,

WILLIAM A. HALL.

Images