Fusion welding

• US 3,895,212 A
• Filed: 02/19/1974
• Issued: 07/15/1975
• Est. Priority Date: 05/10/1972
• Status: Expired due to Term

• Current Assignee: Ernest Thomas Marr, Ian Stuart Maxwell
• Original Assignee: Ernest Thomas Marr, Ian Stuart Maxwell
• Inventors: Maxwell, Ian Stuart, Marr, Ernest Thomas
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Shaw, Clifford C.
• Application Number:
  US05/443,665
• Time in Patent Office: 511 Days
• Field of Search: 219/6R,6A,61,131R,131WR,135 323/89H,94H
• US Class Current: 219/130.33
• CPC Class Codes: B23K 9/073 Stabilising the arc
• CPC Class Codes: B23K 9/1006 Power supply

Abstract

A method and apparatus for fusion arc welding of adjoining workpieces including an arc supply circuit and an arrangement for selectively operating the arc supply circuit in constant-power mode.

Claims

1. A fusion arc welding apparatus adaptable for use with rotating and stationary work pieces and comprising a welding head including non-consumable electrode means disposed for weldably uniting adjoining regions of the workpieces, said welding head being rotatable along an orbital path about the workpieces, the improvement comprising a constant voltage source and a direct current arc supply circuit, a transducer, transfer means connected with the transducer, said transfer means being operable for selecting between having the transducer connected to receive an input current from the constant voltage source thereby influencing the arc supply circuit to operate in constant-current mode and having the transducer connected to receive an input current from the arc supply circuit thereby influencing the circuit to operate in constant-power mode, said transducer having a semi-conductor with the input current passing therethrough, separate electric cable means connecting the arc supply circuit to said workpieces and electrode means, said workpieces'"'"''"'"' related cable means having an intermediate portion thereof wound about the semi-conductor to produce a magnetic field there-across, said magnetic field interacting with the current passing through the semi-conductor to generate an output voltage proportional to the product of the magnitude of the magnetic field and the level of semi-conductor current, a comparator connected to the transducer to receive said generated voltage and to means providing a predetermined voltage input, said comparator producing an output voltage representative of the resultant difference between said generated and predetermined voltages, a thyristor connected to the comparator to receive the output voltage therefrom, said thyristor producing a current output representative of the comparator voltage output, and said arc supply circuit being connected to the thyristor and responsive to said current output to regulate the level of current flowing to said electrode means and work pieces.