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Bridge Rectifiers


spamonkey8

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I've been toying around and I had an idea. I have a transformer that can supply 26VAC/15A. If I run this through a bridge rectifier, I get about 24VDC

(this rectifier drops about 2V). I have two of these handy little rectifiers that can handle 25A at 50PIV max. For my application, I need electricity much as it is supplied with an arc welder, low voltage (about 2V) and high current (the more the better).

 

Here's the question:

 

Hooking two loads to a source of power in series allows the max current to flow whilst splitting the voltage (in the simplest case). What happens when I wire two rectifiers in series? I have confirmed that the voltage is split between the two, and I know that if I wire both rectifiers' DC outputs in parallel, the fact that they are in series doesn't matter, and only half of each rectifier is actually used, thus giving me the 24V. The question is this, how much current could I safely draw from each rectifier at 12V given they are both connected to separate but equal loads. (no pun intended)

 

I've included a simple drawing for visualization (ignore that the outputs are in parallel). I'm a bit over my head, thanks for your time and expertise everyone!

BR.bmp

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Perhaps I am missing something but you only have 15A max from your transformer. The bridges will handle 25 amps, 10 more then your transformer will deliver. If you want to drop the voltage, I would suggest a voltage regulator. There are many available as either fixed or variable voltage and many can be paralled or used to drive a power transistor to do the regulation for high currents.

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You're going to have to find yourself another transformer. There's no way around that.

 

The transformer doesn't care how many bridge rectifiers you drop the voltage across. The voltage across the output of the transformer will still add up to 26vac and the maximum output current will still be 15A.

 

The only way to trade excess voltage for more current is through a transformer AFAIK.

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  • 5 weeks later...
and the maximum output current will still be 15A.

In case the idea isn't clear here, the maximum SAFE output current will be the rated one. If you drop the load resistance too low, more current will flow out of the xformer but this will heat it up and cause a meltdown/short/open circuit. In the process, there is a fire and shock risk, and dangerous gases may be released from the insulating and construction materials burning.
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