Full wave bridge w/ only two diodes given center tapped x-former?

I am no longer convinced that you [always] need more than 2 high current diodes for a full wave bridge, to shape the wave-form of a North American 110v wall receptacle from AC into DC. In my case, the output of my transformers secondary is center tapped to negative. Here is a picture of what I am talking about: http://en.wikipedia.org/wiki/Rectifier along with a description of "single phase full wave rectification" with only two diodes and a center tap x-former. Is there a reason this AC to DC circuit wouldn't work this shottky barrier diode, which, if you scroll down on its data sheet here: http://www.sanrex.com/images/PDFs/BKR400AB10.pdf appears to be nothing more than two massive diodes already wired in proper polarity/configuration?? Thanks.

 

Thank you for delineating, Alchymist; clarifying GreenGiant; more facts still, Electrobrains. This is to rectify into DC, an AC "stick" welder made from 2 rewound microwave oven transformers, like this: http://www.instructables.com/id/Build-a-Microwave-Transformer-Homemade-Welder/?ALLSTEPS. Since it has two transformers' outputs wired in series, one might tap between them (it is not currently wired that way, I mis-spoke)...but maybe not at the expense of a division of voltage/efficiency of the 2 diode system, like Alchymist describes. On the other hand, Electrobrains describes downsides to the bridge, too. My guess is that for the weld to start/maintain arc, it simply wouldn't work with less than the ~40 V (DMM measured [x 1.4 = peak VAC according to above post]) equals 56 VAC peak. That's the only measurement I took other than to make sure the two rewound x-formers were not "fighting phase'. If it matters I suppose I could test output current to load with my clamp ammeter function. ???

 

Wow, you folks are way more grounded in the physics/theory than me. I don't have the level of understanding of some of you, but I sure appreciate that you do. Here is a picture I took back when I wound one of the two transformers' secondary with #10g copper braided wire. The other one is wound similar, and they are connected in series such that where their two secondaries are connected into one, there is a point that could potentially be used for a center-tap. As of now, that "center-tap", albeit in reality just a tap point between two separate secondaries of two separate cores of two separate x-formers, is what might be used for full wave with only two diodes. As it stands and functions today, that point between the two is connected to nothing other then the other transformer. I am only assuming they are in phase with each other because when I measured them in series their combined voltage seemed double their individual. Hope this helps inform all the more complex concepts you are mentioning. It seems like it should be the bridge option in order to keep final output voltage high enough to strike arc, as first described by Alchymist...on the other hand...???

 

Points well taken. That most welders out there will outperform my bush league garage project is true, just not for this price. On the other hand, the authors of that project were at least ostensibly professors of engineering at MIT, and their stated reason theres would outperform commercial cheap AC stick welders is that their design is pure copper. I'm certainly also glad that welders (I'm very novice) take such pride in their work, particularly structural enough for life to depend on it. This is nothing like that. This is more for tinkering and light projects.

 

Basically, I'm reading that: 1) DC is overall smoother to deal with and better to learn on because, although they are all different, it more closely resembles some of the other modern welding systems; 2) It's supposed to be more versatile because you can choose whether to make the electrode the workpiece or the filler material. In so doing you can weld thin metal better with one polarity, thick better with the other. At least that's what I read...I'm new to all this.

 

Drawbacks to be sure. If this project-in-evolution works, adding a inductive "reactor" like you describe might be next.