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US RE29,400 EGranted
Direct current power supply for manual arc welding
AssigneeElektriska Svetsningsaktiebolaget
InventorRolf Ericsson
Life of this patent
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Abstract
A direct current power supply for manual arc welding comprising a polyphase transformer, a polyphase rectifier system including triggered rectifier valves, and a control system therefor which comprises means for setting the output current level by adjustment of a reference signal, means providing negative feed-back of the output voltage and the output current, and means for adjusting the slope of the characteristic by adjustment of the proportion between the amounts of feed-back of the voltage and the current. The current level setting means and the slope adjustment means are linked with each other to provide automatically a desired correlation between the slope and the current setting.
Claims10
A direct current power supply for manual arc welding having a steeply drooping, adjustable volt-ampere characteristic comprising
- a polyphase transformer having a plurality of secondary output leads carrying mutually phase displaced voltages, a polyphase rectifier system connecting said secondary output leads to a pair of D.C. welding current conductors for supplying a direct current to a welding arc struck between a welding electrode and a workpiece, said polyphase rectifier system comprising a set of triggered rectifier valves connected one in series with each of said secondary output leads, said triggered rectifier valves having each a trigger terminal for initiating current flow through the valve,
- means for periodically supplying igniting pulses to each of said trigger terminals, including means for causing the angular position of said pulses to vary in response to a direct current control signal,
- means for generating said direction current control signal comprising the following means,
- a. means for producing an adjustable direct current reference signal, including manually operable means for adjusting said reference signal,
- b. means including a welding current sensing means for producing a welding current feed-back D.C. signal equal to the welding current flowing in the pair of welding current conductors multiplied by a first factor of proportionality,
- c. means including a welding voltage sensing means for producing a welding voltage feed-back D.C. signal equal to the voltage between the welding current conductors multiplied by a second factor of proportionality,
- d. summing means for combining said reference signal, said welding current feed-back signal and said welding voltage feed-back signal into a compound signal constituting said control signal, both of said feed-back signals being supplied to said summing means in opposing relationship to said reference signal,
- e. slope adjustment means comprising means for adjusting the proportion between said first and second factors of proportionality, and,
- f. means linking said manually operable means for adjusting the reference signal and said proportion adjusting means to provide automatically a desired correlation between the slope of volt-ampere characteristic of the power supply and the reference signal setting.
6 more elements
A direct current power supply for manual arc welding having a steeply drooping, adjustable volt-ampere characteristic comprising
- a polyphase transformer having a plurality of secondary output leads carying mutually phase displaced voltages, a polyphase rectifier system connecting said secondary output leads to a pair of D.C. welding current conductors, said polyphase rectifier system comprising a set of triggered rectifier valves connected one in series with each of said secondary output leads, said triggered rectifier valves having each a trigger terminal for initiating current flow through the valve,
- means for periodically supplying igniting pulses to each of said trigger terminals, including means for causing the angular position of said pulses to vary in response to a direct current control signal,
- means for generating said direct current control signal comprising the following means, to wit,
- a. means for producing an adjustable D.C. reference signal, including manually operable means for adjusting said reference signal,
- b. means including a welding current sensing means for producing a welding current feed-back D.C. signal equal to the welding current flowing in the pair of welding current conductors multiplied by a first factor of proportionality,
- c. means including a welding voltage sensing means for producing a welding voltage feed-back D.C. signal equal to the voltage between the welding current conductors multiplied by a second factor of proportionality,
- d. A capacitor connected in series with a resistor, means including a welding voltage sensing means for submitting said series connection to potential variations proportional to the variations of the welding voltage, and means for producing a transient feed-back signal equal to the voltage appearing across said resistor multiplied by a third factor of proportionality,
- e. summing means for combining said reference signal, said welding current feed-back signal, said welding voltage feed-back signal and said transcent feed-back signal into a compound signal constituting the control signal aforementioned, said welding current feed-back signal and said welding voltage feed-back signal being supplied to said summing means in opposing relationship to said reference signal, transient feed-back signals caused by discharge of said capacitor on decrease of the welding voltage being supplied to said summing means in aiding relationship to said reference signal,
- f. transient slope adjusting means comprising means for adjusting the proportion between said first and said third factors of proportionality, and,
- g. means linking said manually operable means for adjusting the reference signal and said proportion adjusting means to provide automatically a desired correlation between the transient slope of the voltage-ampere characteristic of the power supply and the reference signal setting.
7 more elements
Dependencies are inferred from the claim text.