US1412463A - Constant-current arc-welding system - Google Patents

Description

W. B. ELLIOTT AND W. OBLENIS.

CONSTANT CURRENT ARC WELDING SYSTEM.

APPLICATION FILED MAR. 14, 1918.

1,412,463; Patented Apr. 11, 1922.

. INVENTORS BY fit ALv-fi ATTORNEY UNITED STATES PATENT-OFFICE.

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con'srm'r-cunnm ARC-WELDING sxsrmm;

Specification 0t Letters2aten t.: Pate t d A 11 1 2 I .Application filed March 14, 1918. Serial No. 222,277.

Toall whom it may concern:

Be it known that we, WILLIAM B. ELLIo'rr and WILLIAM [-OBLnms, citizens of the United States, both residing at Westfield,

county of Union, State of New Jersey, have invented new and useful Improvementsin Constant-Current Arc-Welding Systems,- of which the following is a speclfication.

This invention relates to a system for welding, brazing or otherwise treating metals by means of the electric arc,

Where the arc is fed from a constant potential, it is very unstable. This has been overcome to some extent by placing resistance in circuit with the are, but this is a wasteful proceeding. A much more efficient method is to vary the voltage impressed on the arc electrode according to the resistance of the arc. For this purpose, the generator .supplyin the voltage may be so regulated that the field excitation, and consequently the voltage will be lowered when the current increases, due to --the lowering of the resistance of the arccircuit as by decrease in the resistance of the arc. Conversel the excitation of the generator shoul be increased with anincrease in the resistance of the arc circuit. 4

The present invention has for its main object the provision of improved means for effecting the regulation of the voltage in the arc circuit, which means is especially adapted to regulate the voltage in the man- I ner as just described and which is also suitable for regulationof the arc circuit in other respects.

Other and ancillary objects of the invention will appear hereinafter.

The accompanying drawing, which illustrates the invention, isa diagrammatic I showing of apparatus and connections of a" system embodying the invention.

Referring to the drawing, the arc is adapted to be formedbetween the work 1 andan electrode 2, and is supplied with current by means of a direct current gen- .erator including the armature 3, the series field 4 and the field 5, One terminal of the armature 3 is connected through the series field 4: and the series field 6 of an exciter to be further referred to hereinafter, with the electrode 2. The other terminal of the generator is connected with the work 1. The field 5 is supplied with current by a compound wound exciter comprising the armature other terminal of the field 5. The rheostat 10 is forthepurpose of initial adjustment of the field current in winding 5. The main generator has its fields arranged differentially, that is, the fields 4 and 5 are opposed The series field may to each other so that as the series field strengthens, the total field excitation of generator will be reduced. -The exciter being compound wound, the shunt and series-fields 8 and 6 act in conjunction so that a strengthening of the series field strengthens the resultant field on the exciter; V

Withthe electrodes 1 and 2 separated and no current flowing, the voltage of the'main generator supplying the arc will be that due to its field 5, which is excited by the exclter armature 7 subjected to the excitation of the shunt field 8 only. The series fields 4 and 6 have no effect as no current is flowing. Under these conditions, the voltage is such that when the electrodes 1 and 2 are touched together to strike the are there will not be an undue' rush of current. As soon as current flows in the arc circuit, however, the current through the series field 6 of the exciter, will cause an increase in the field of the exciter with a consequent 'increase'in the voltage, with a resultant increase in current through the field 5, which tends to increase the strength of the field of the main generator and therefore its voltage. The voltage therefore impressed on' the arc circuit is increased over the low voltage which exists at the timethe electrodes are brought together, but a great rush of current is prevented by reason of the fact that the bucking series field a which carries the working current, decreases the the main generator voltage. Normal workto. decrease in the arc circuit resistance and conversely it will tend to prevent decrease of current in the arc circuit upon an %Vhat we claiinis- 1.' The combination of a circuit having a load device varying widely in resistance, a generator supplying said load device, said generator comprising a main field w1nding,

. an auxiliary source of electromotive force supplying said main field winding, and means responsive to conditions in said circuit for regulating said source, said generator also comprislng a series fieldwinding opposed to said main field winding.

2. The combination of a circuit having a generator supplying said load-device, said generator comprising a main field winding,

and an auxilia generator su plying said main field win ing, said auxi iary generator having a shunt field winding and a field windin connected in series in said circuit, said rst named generator also having a series field winding opposed to said main field winding.

The combination of a circuit having a load device varying widely in resistance, a generator supplying said load device, said generator comprising a main field winding, and an auxiliary generator supplying said main field windin said auxiliary genera-tor having a shunt eld winding and a field winding connected in series in said circuit and said last two named windings having an additive effect, said first named generator having a series field winding opposed to said main field windin In testimony wIxereof we have signed this specification this 23d day of February,

' WILLIAM B. ELLIOTT.

WILLIAM OBLENIS.

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