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  High current ac welderUSPTO Application #: 20070215585Title: High current ac welder Abstract: An electric arc welding assembly comprising a charging circuit and regulator coupled to an input power source, an energy storage element connected in parallel with the charging circuit and regulator to increase the power available for the weld output, and a weld output controller connected in parallel with the energy storage element for controlling a welding arc between an electrode and a workpiece. (end of abstract)
Agent: Fay Sharpe / Lincoln - Cleveland, OH, US Inventor: James J. O'Connor USPTO Applicaton #: 20070215585 - Class: 219130100 (USPTO) Related Patent Categories: Electric Heating, Metal Heating (e.g., Resistance Heating), By Arc, Including Arc-power Supplies The Patent Description & Claims data below is from USPTO Patent Application 20070215585. Brief Patent Description - Full Patent Description - Patent Application Claims
INCORPORATION BY REFERENCE [0001] The following related applications, the disclosures of each being totally incorporated herein by reference, are mentioned: [0002] U.S. patent application Ser. No. 10/919,815, filed Aug. 17, 2004, entitled "HYBRID POWERED WELDER," by William T. Matthews, et al.; and [0003] U.S. patent application Ser. No. 10/815,536, filed Apr. 1, 2004, entitled "EXTENSION LIFT TRUCK MODIFICATION," by John M. Stropki, Jr., et al. FIELD OF THE INVENTION [0004] The present invention relates generally to the art of welding. It finds particular application in conjunction with high current welding power supplies receiving an AC input, and it will be described with particular reference thereto. However, it is to be appreciated that the present invention is also amenable to other like applications. BACKGROUND OF THE INVENTION [0005] Many welding applications need to be performed using welding power supplies that are able to be plugged into a standard 110-120 volt AC, 60 Hz outlet, such as the type that may be found in most homes, offices, and businesses. Because of the low output voltage of the standard AC outlet, a relatively high current is needed from the outlet to melt the electrode and base material. However, the typical AC input for such an outlet may be limited to only 15 (or 30) amps by a circuit breaker, which may also serve other AC outlets as well. Accordingly, the power that may be obtained from such an AC outlet is limited, thus further limiting the power that may be provided to the weld. [0006] Since standard AC outlets are limited to 15 (or 30) amps typically, this only allows for approximately 1800 (or 3600) watts of power for welding applications. Thus, for example, assuming a 90% efficient design and a power factor of 1, the available welding power for a 30 amp circuit at 120 volts AC would be only 3240 wafts. For various welding processes, this amount of power would produce the following welding currents: [0007] Stick Welding--130 A [0008] MIG Welding--150 A [0009] TIG Welding--185 A [0010] This power is available 100% of the time. However, many welding applications need more current. Thus, because most welding is not at 100% duty cycle, it would be helpful to use the power during the non-welding time to charge an energy storage device. Such a device could be any number of things --most commonly a battery. This stored energy alone or combined with power from the outlet can be used to produce any amount of welding power. [0011] Some prior art AC welders provided an unbalanced output to offset the naturally occurring unbalanced load when using a tungsten electrode, while yet other types of known welding power supply use only battery power as an input. However, these types of power supplies are generally limited in the amount and in the duration of power .that they can provide for welding applications. [0012] U.S. Pat. No. 6,777,649 relates to a welding-type power supply that uses an energy storage device, such as a battery, as a voltage boost mechanism. Generally, this patent provides for welding from a standard AC duplex outlet and provides up to a 150 amp output, at an output voltage of up to about 25 volts. A battery is provided after the voltage regulation and in series with the welding output, such that the battery simply "boosts" (or adds to) the output voltage. Thus, the power circuit need only provide a 12 volt. output, with an additional 12 volts coming from the battery. However, the power supply in this patent does not pull any extra current from the energy storage element, i.e., the battery is not being charged during the non-welding time. [0013] Thus, it would be preferable to use an energy storage element that can be charged from a standard 110-120 volt AC outlet at a 15 to 30 amp rate, but will also be able to provide higher power output for short periods of time for a welding operation. By using different charging systems, the welder could be adapted to work with various input supplies, AC or DC, as well as high or low power levels. Using such a system, it would be possible to get unlimited welding current. The amount of welding current would be dependent on the size of the energy storage element. BRIEF DESCRIPTION OF THE INVENTION [0014] In accordance with an aspect of the present invention, there is provided an electric arc welding assembly comprising a charging circuit and regulator coupled to an input power source, an energy storage element connected in parallel with the charging circuit and regulator to increase the weld power output, and a weld output controller connected in parallel with the energy storage element for controlling a welding arc between an electrode and a workpiece. [0015] In accordance with other aspects of the present invention, the energy storage element may comprise at least one battery and/or at least one capacitor. Optionally, at least one battery and at least one capacitor may be connected in parallel, to provide additional power for certain welding applications. [0016] In accordance with yet other aspects of the present invention, the weld output controller may comprise various types and combinations of circuits. For example, the weld output controller may comprise a DC down chopper, wherein the DC down chopper includes a pulse width modulator that at least partially controls the welding current to the electrode and a waveform generator that at least partially controls the pulse width modulator, the DC down chopper creating a series of current pulses that constitute a welding cycle representative of a current waveform, the pulse width modulator controlling a current pulse width of a plurality of the current pulses. Likewise, the weld output controller may comprise a forward converter/inverter, wherein the forward converter/inverter includes a series circuit of a primary winding of a transformer and a switching element, which is coupled to the energy storage element and a rectifier smoothing circuit which rectifies and smoothes a voltage induced in a secondary winding of the transformer according to a switching operation of the switching element, wherein a rectifier element of the rectifier smoothing circuit conducts during an ON period of the switching element. The weld output controller may also comprise a boost converter. [0017] Moreover, the weld output controller may comprise a combination of power topologies. These could have high and low current capability. Thus, the weld output controller may comprise a current limited boost circuit connected in parallel with a high current circuit, such as a DC down chopper, for certain applications. This combination circuit would offer particular advantages when stick welding with energy storage elements of less than 70 volts. Some stick electrodes, such as the E-6010 class from The Lincoln Electric Company of Cleveland, Ohio, require high currents from 100 to 300 amps at 25 volts and below, but they also require a higher voltage from around 50 to 60 volts at a lower current (60 amps) to produce an acceptable arc. [0018] In accordance with yet other aspects of the present invention, the input power source may comprise a 110-120 volt AC wall outlet or a 220-240 volt AC wall outlet, and the apparatus may also include an input cord and three-prong plug for connecting to the appropriate AC wall outlet. BRIEF DESCRIPTION OF THE DRAWINGS [0019] FIG. 1 is a block diagram of a high current AC welding assembly in accordance with aspects of the present invention. Continue reading... Full patent description for High current ac welder Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this High current ac welder patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like High current ac welder or other areas of interest. ### Previous Patent Application: Method and apparatus for bonding electronic elements to substrate using laser beam Next Patent Application: Nickel alloy welding wire Industry Class: Electric heating ### FreshPatents.com Support Thank you for viewing the High current ac welder patent info. IP-related news and info Results in 3.68982 seconds Other interesting Feshpatents.com categories: Tyco , Unilever , Warner-lambert , 3m |
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