beerbarrel wrote:

On Sat, 08 Jan 2005 20:42:35 -0500, John Popelish
wrote:


beerbarrel wrote:

Anyone have a source for a schematic for a 12v around 20 to 30 amp
power supply that makes use of a full wave rectifier? I've found quite
a few for a bridge rectifier but I'm not really sure how to mod them
to use a full wave rectifier. I have a nice 32v 30 amp center tapped
at 16v transformer that I would like to make use of.

Thanks...

You can use half of your bridge with this transformer to produce
something like 22 volts DC at the filter cap. Connect each end ot the
secondary to one of the AC inputs ot the bridge and connect the cap
and load between one of the DC connections of the bridge and the
center tap. If you use the + terminal of the bridge, it will be the
positive output. If you use the - terminal of the bridge, the center
tap will be the positive output.

The bridges will handle a bit more current than they are rated for,
because only two of the 4 rectifiers will be getting hot. They will
certainly need a heat sink for anything like 20 amperes out, though.

After you get that working and running a couple 12 volt headlights in
series (at least), you can start thinking about how to regulate this
down to 12 volts.



Thanks John...

I saw that particular setup somewhere while I was looking for a
schematic. I would really like to try to use the transformer as
designed if I could. It would be nice to throw it into some of the
good schematics that I've seen on the net. I might wind up using the
one secondary and the centertap if I can find something.

It does use the transformer as-designed -- it just doesn't use all of
the bridge rectifier. This is what you're trying to do:


To load
-. ,------|------o---------
)|( |
To mains )|(---. |
)|( | |
-' '------|------o
| |
| | +
=== ###
GND ---
|
|
===
GND
created by Andy´s ASCII-Circuit v1.24.140803 Beta www.tech-chat.de


--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com