Welding system with arc control

Abstract

A method and apparatus for controlling arc/short between a wire and a work piece is described. A current path parallel to the wire/work is provided. The voltage drop across the parallel path can be preset, to limit the wire/work voltage, or it can be controlled to a desired level. The control can be in response to feedback.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A welding-type system, comprising:
 a power circuit disposed to provide welding-type power on a first electrode and a second electrode, wherein the power circuit has at least one control input;   an arc clamp module, electrically coupled to the first electrode and the second electrode; and   a controller, having a power circuit control output connected to the at least one control input.   
     
     
         2 . The welding-type system of  claim 1 , wherein the arc clamp module is an active arc clamp module and has an arc clamp control input, and wherein the controller has an arc clamp control module having an arc clamp control output connected to the arc clamp control input. 
     
     
         3 . The welding-type system of  claim 2 , further comprising a feedback circuit electrically coupled to at least one of the first electrode, second electrode, and arc clamp module, wherein the feedback circuit is disposed to provide a feedback signal to the controller, wherein the arc clamp control output is responsive to the feedback signal. 
     
     
         4 . The welding-type system of  claim 3 , wherein the feedback circuit includes a current sensor, and wherein the arc clamp control output is responsive to the current sensor. 
     
     
         5 . The welding-type system of  claim 4 , wherein the feedback circuit includes a voltage sensor, and wherein the arc clamp control output is responsive to the voltage sensor. 
     
     
         6 . The welding-type system of  claim 3 , wherein the feedback circuit includes a voltage sensor, and wherein the arc clamp control output is responsive to the voltage sensor. 
     
     
         7 . The welding-type system of  claim 2 , wherein the arc clamp control module is at least partially implemented using hardware. 
     
     
         8 . The welding-type system of  claim 2 , wherein the arc clamp control module is at least partially implemented using software. 
     
     
         9 . The welding-type system of  claim 2 , further comprising a wire feeder electrically coupled to at least one of the first electrode and second electrode. 
     
     
         10 . The welding-type system of  claim 9 , wherein the arc clamp module is electrically coupled to at least one of an output of the wire feeder and an input of the wire feeder. 
     
     
         11 . The welding-type system of  claim 1 , wherein the arc clamp module comprises at least one of a transient voltage suppressor, a diode, and a plurality of diodes, arranged such that a voltage drop across the arc clamp module limits the current in the arc for the voltage drop across the arc clamp module. 
     
     
         12 . The welding-type system of  claim 11 , wherein the arc clamp module comprises the plurality of diodes, and wherein the arc clamp module further comprises a plurality of voltage taps, each disposed between at least two of the plurality of diodes, and wherein each voltage tap is also electrically connectable to the second electrode. 
     
     
         13 . The welding-type system of  claim 12 , wherein each of the plurality of voltage taps is electrically connectable to the second electrode by at least one of a manual switch and a electronically controlled switch. 
     
     
         14 . The welding-type system of  claim 11 , wherein the arc clamp module further comprises at least one transistor disposed to control the voltage across the arc clamp module. 
     
     
         15 . The welding-type system of  claim 1 , wherein the arc clamp module comprises at least one transistor disposed to control the voltage across the arc clamp module. 
     
     
         16 . A method of controlling welding-type power, comprising:
 providing welding-type power on a first electrode and a second electrode, wherein a working current path is between the first electrode and the second electrode; and   controlling at least one of current through the working path and voltage across the working current path by providing a bypass current path.   
     
     
         17 . The method of  claim 16 , further comprising providing feedback from the working current path and controlling the bypass current path in response to the feedback from the working current path. 
     
     
         18 . The method of  claim 17 , wherein the feedback is responsive to at least one of current in the working current path and voltage across the working current path. 
     
     
         19 . A welding-type system, comprising:
 means for providing welding-type power on a first electrode and a second electrode, wherein a working current path is between the first electrode and the second electrode;   means for controlling the means for providing welding type power, connected to the means for providing welding type power, wherein the means for controlling receives feedback from the working current path; and   means for current to bypass the working current path.   
     
     
         20 . The system of  claim 16 , wherein the means for current to bypass includes controllable devices, and the controllable devices are connected to the means for controlling.