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Old January 10th 05, 02:56 AM
John Popelish
 
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beerbarrel wrote:

On Sun, 09 Jan 2005 16:25:55 -0500, John Popelish
wrote:

beerbarrel wrote:

Let me rephrase what I said, or what I meant to say. I have a 32v
transformer that is centertapped at 16v. It has the diodes in place
for a full wave rectifier.


Two diodes or 4?

I want to construct a linear PS from this.
I don't really want to add a bridge to make this work in another
configuration. What I need is a schematic that allows use for a high
current transformer (30 AMP) using this configuration. I would like to
get max current out of the transformer. I realize that I could use one
of the secondaries and the center tap with a bridge to make a PS and I
might have to do that. I think that it would cut into my current
rating heavily though. Any thoughts?


2

The transformer was removed from a automotive battery charger and has
2 heavy duty rectifiers pressed into a heavy aluminum plate. I have a
65000 mF cap band ready to go for the filter.


Then you have the basis for a high current supply. You could get a
slight increase in current capability by separating the two halves of
the secondary, put a 4 diode bridge in each half and connect the
outputs of those bridges in parallel, but the view is probably not
worth the climb unless you really need every ampere this thing is
capable of. And in that case you would want a switching regulator to
convert volts to amperes, instead of a linear regulator. Lots more
difficult.

Here is the data sheet for a control chip commonly used for high
current linear regulators. The application notes (figure 5) give the
general idea of what is required. You will have to come up with a
bank of pass transistors (6 to 10 TIP36, perhaps and a big heat sink).

http://cache.national.com/ds/LM/LM723.pdf
--
John Popelish