US1292397A - Electric-arc-welding system. - Google Patents

Description

J. KJEKSTAD.

ELECTRIC ARC WELDING SYSTEM.

'APPLICATION FILED OCT. 19, 1918.

gay: Z

r0 GROUND z I 2d 3 j II /J 0 z Z Z.

WITNESS: INVENTOR.

A TTORNEYS.

JOHANNES KJ'EKSTAD, OF BROOKLYN, NEW YORK.

ELEGTRIC-ARC-WELDING SYSTEM.

Specification of Letters Patent.

Patented Jan. 21, 1919.

Application filed October 19, 1918. Serial No. 258,901.

To all whom it may concern.

Be it known that I, JOHAXNES KJEKs'rAn, a subject of the King of Norway, residing at the city of Xew York. borough of Brooklyn. and State of New York, have invented certain new and useful Improvements in Electric-Arcelding Systems, of which the following is a full, clear, and exact description.

My invention is broadly applicable to both metallic arc welding and carbon arc welding, and has for an object the provision of means in such a system for automatically keeping the energy at the are constant within certain limits.

Another object is to obtain this result with a minimum dissipation of energy in external resistances or other regulating devices, whereby economy in energy consumption is effected.

Another object is to provide a regulating system capable of use with one or a plurality of welders in the same system.

Other objects and advantages of my invention will appear from the following description.

Various systems have heretofore been proposed for stabilizing wattage consumption at the arc, but these have commonly comprised automatically variable resistances, which. of themselves. consume considerable of the energy supplied to the circuit. My invention comprehends as a regulating device an auxiliary source of energy operative to supply to the circuit more or less energy as is demanded to maintain the wattage substantially constant. In its preferred adaptation, my invention contemplates an automatic regulating device, which is responsive to the variations in'current to inversely regulate the voltage impressed upon the line. and thereby maintain the wattage substantially constant.

More specifically, the regulating device is itself a source of electro-motive force, which is positive or active relative to that of the main generator. so long as the current is below a predetermined amperage, and is negative or counter when the current rises above the predetermined amperage, while at the predetermined amperage the regulating device is inactive or passive.

In this specific embodiment. the voltage may at all times be considered to be resultant of two components. In the equation z-a w, in which 2' equals the voltage, and a as r or the electro-motive force of the main generator, and v, is a variable counter electro-motive force. e then have the equation In this equation o, and a are directly variable, with the result that w remains substantially constant.

Figure l is a diagram of one embodiment of my invention showing a main and auxiliary generator with their circuit arrangements.

Fig. 2 is a diagram showing the circuit arrangement of a system embodying my invention and comprising a plurality of welding arcs.

In my improved system, I use a main (1. c. generator of such size as to give the desired voltage and amperage for one welder, if only one is to be used in the circuit, or of such size as to give the same amperage for each welder if a plurality of welders are included in the circuit. In series with the main generator is used an auxiliary regulating generator for each welder, which is differentially wound with the shunt coil excited by the main generator and a series coil so proportioned and connected as to neutralize the shunt field when a predetermined amperage is passing through the arc.

Referring to Fig. 1, the main generator 1 is shunt wound and of such size and capacity as to generate sufficient electro-motive force to force the desired current across each are under proper conditions. \Ve will assume, for example. that the generator 1 generates '20 volts pressure with a current of 150 amperes across each arc. under ideal are conditions. This voltage remains substantially constant while the amperage and hence the wattage varies with the resistances across the arc.

To compensate for this variation, the auxiliary regulating generator 2 is used in series with the main generator. The positive tive brush of the armature 2 is connected to the series field coils 2 which are connected to the wire 4: leading to the ground,

and the negative brush of the main generator is connected by a wire 5 to the electrode.

- The shunt field 2 of the auxiliary generator is connected across the leads from themain generator armature, and the two field windings 2 and 2 are wound in opposition to each other, the series coils being so proportioned as to neutralize the shunt field when the predetermined desired amperage is passing through the arc, which in the supposed case is 150 amperes.

The shunt coils 2 of the auxiliary generator 2 serve as a separate source of excitation for the field, which is substantially constant. If we assume that the auxiliary armature on open circuit, by reason of the shunt field excitation, gives 40 volts in the same direction as the main generator, with which it is in series, then the total electro-motive force to start the arc will be 60 volts. When 150 amperes pass through the arc and the series coils 2 of the auxiliary armature, the shunt field 2 of the auxiliary .armature is neutral-.

ized, and the armature 2 then gives no voltage and acts only as a reactance. The are will then have the twenty volts of the main generator, and if the current in the arc falls 3 below 150 amperes, the auxiliary generator will supply some voltage proportionate to the extent of drop of the amperage, which will help to maintain the arc; and if the current in the arc goes above 150 amperes, the auxiliary armature will generate a-volt- .age against the main generator, and tend to prevent an excessive rise in current. In other words, the auxiliary generator acts as a .booster when the current across the arc is below a predetermined amperage, and acts stand that the size and capacity of the to buck the main generator, if the current rises above the predetermined amperage.

Bythis means I am enabled to have at all times substantially a constant amount of energy in the arc, .while dispensing with all series resistances for steadying the arc.

It will be understood that the figures given above are only by way of illustration, and those skilled in the art will readily underenerators may be varied to obtain any desired result. 'They may-be so proportioned, for example, as to have the same size frame, in which case all arts, except field coils, will be interchangea Is, an obvious advantage in appearance and manufacture.

Fig. 2 illustrates one way in which my invention may be applied to a system including a plurality of arcs. In the system shown there are three arcs although it will be unbeing only necessary to make the main generator 1 of the requisite capacity. For instance, if 150 amperes at 20 volts pressure be desired at each arc, then in the system shown the generator 1 will have a capacity of 20 volts and 150 amperes. An auxiliary generator similar to the one above described is used for each welder.

It is obvious that various modifications may be made in the construction shown in the drawings and above particularly described withln the principle and scope of my invention.

I claim;

1. In an electric arc welding system, the combination with means for impressing a voltage upon the welding circuit, of a regulating device operative to impress another and a variable voltage upon the circuit.

2. In an electric arc {welding system, the

combination with means for impressing a. voltage upon the welding circuit, of a regulating device responsive to the current in the welding circuit to impress another and a variable voltage upon the circuit.

3. In an electric arc welding system, the combination with a main generator in the welding circuit, of an auxiliary regulating generator operative to impress a variable voltage upon the circuit and maintain the wattage at the are substantially constant.

4. In an electric arc welding system, the combination with a constant voltage generator in the welding circuit, of an auxiliary regulating generator operative to impress a voltage upon the circuit and responsive to the current in the circuit to vary its voltage.

5. In an electric arc welding system, the

combination with a source of electro-motive force, of a regulating device responsive to variations in the welding current for impressing upon the circuit a variable counter electro-motive force.

6. In an electric arc welding system, the combination with a constant voltage generator in the (welding circuit, of an auxiliary regulating generator operative on open circuit to impress an additional predetermined voltage upon the line and upon closed circuit to generate a counter electromotive force variable with the current in the circuit.

7 In an electric arc welding system, the combination with a source of electro-motive force in the welding circuit, of an auxiliary regulating generator in the circuit separately excited or generating an electro-motive force and responsive to the variable current in the circuit to generate a counter electro-' motive force and thereby vary its voltage impressed upon the line and maintain the wattage at the are substantially constant.

8. In an electric arc welding system, the combination with a source of electro-motive force in the .welding circuit. of an auxiliary rately excited for generating an electro-n'io 9. In an electric arc welding system, the

combination with a source of electro-motive force in the welding circuit, of an auxiliary regulating generator in the circuit having two components to its field excitation, one a, separate excitation and the other a series excitation, .the windings of the components being opposed and proportioned to neutralize each other at a predetermined current in the series winding.

10. In an electric arc welding system, the

combination ,with a main constant voltage generator in the welding circuit, of an auxiliary regulating generator in the circuit having its armature connected in series with the main generator'and having its field energized by a series winding and by a winding in shunt with the mam generator, theseries and shunt windings being opposed andproportioned to neutral ze ata predetermined current in the series Winding.

In w tness ture.

, JoHANNEs KJEKSTAI).

whereof I subscribe my sigma-1

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