On Oct 5, 9:11*pm, Grumpy The Mule wrote:
You might find this useful Jimmie.

I had some time to cobble together a DC-DC "transformer" this weekend.
It is a half-bridge running at 200KHz and fixed 96% duty cycle. The
turns ratio is 1:24 and the output is full wave rectified. I'm using
an EDT29 core, I think the material is 3C90.

The rectified AC line was ~160V and the output was ~1800V (I'm using
a Simpson 260 so the voltages are thereabout.)

After running 300 watts though it for two hours the transformer wasn't
near warm. *If I take this further I need to build a real load.
A bucket of distilled water and some magnesium sulfate (epsom salt)
isn't stable when it's boiling.

It's a small transformer and light. *It's not regulated but I think it
could replace a much larger laminated steel transformer.

Takes a rainy day for me to find any motivation for stuff like this.
Maybe after winter arrives I'll build it up properly and try it in
the SB200.

73

wrote :



The 300 volts you wanted is on the input side of the power supply, not
what you wanted. This does not mean that the output of the power
supply is not isolated from the mains. The type of switching power
supply you wanted is probably doable. Think about removing the output
transformer from a PC power supply and connecting it back to back with
the transformer in a working power supply. The output could be
rectified and filtered and you would have a cheap to free lightweight
line isolated HV power supply. I am in thr process of trying this. I
not getting much work done on it due to my present work schedule but
in a few weeks things should get back to normal and I will have a
chance to play with my toys some more.

I am just getting in to SMPSs and find it amazing what these things
willl do.
For example I found a a +- 15 volt unit that puts out 100 amps for
each voltage. I can hold the output transformers in my hand, they
couldnt weigh more than a pound each.

Jimmie- Hide quoted text -

- Show quoted text -

I had a little time yesterday and opened up a PC power supply and
brought the 3 taps off of the transformer out to binding post. The
plan is to build a transformer that will step the voltage back up to
about 800 volts or so, enough for my little 6146B 6M amp.

Jimmie.

JImmie

What will you use for an inductor in the output filter
following the second transformer?



wrote in
:

I had a little time yesterday and opened up a PC power supply and
brought the 3 taps off of the transformer out to binding post. The
plan is to build a transformer that will step the voltage back up to
about 800 volts or so, enough for my little 6146B 6M amp.

Jimmie.

On Oct 8, 7:47*pm, Grumpy The Mule wrote:
What will you use for an inductor in the output filter
following the second transformer?

wrote :



I had a little time yesterday and opened up a PC power supply and
brought the 3 taps off of the transformer out to binding post. The
plan is to build a transformer that will step the voltage back up to
about 800 volts or so, enough for my little 6146B 6M amp.

Jimmie.- Hide quoted text -

- Show quoted text -

Like you said I like to Frankenstien things. I have a filter from
another power supply but I am not sure how well it will work
as it was designed for about 25 amps. Basically thats a bridge I will
jump off of when I come to it. Right now I am having enough trouble
finding an old PC power supply I can get a transformer from. Its hard
to believe about a couple of months ago I tossed about a dozen of
them. Last time I listen to my wife. I do have a couple of
transformers from some old Lambda power supplies. Thes are some really
nice ones probably capable of handling a couple of Kwatts. Im not
ready to experiment with them yet. Although this is learning by
destuction it's cautious destruction. I will probably take a trip down
to the local computer place this weekend and do a little dumpster
diving or make a run on the goodwill store and see what I can get for
$10. IF you havent figured it out by now I love building things from
others discards. When I was in high schooI I built a killer stereo, I
thought at the time, from old stuff I found in the dump that was the
envy of most of my friends. Ive enjoyed doing it ever since.

Jimmie

Jimmie

Cobbling stuff together is lots of fun. From Pressman's
book you can figure out the inductor value.

I'm guessing a powdered iron toroid from the output of a PC
power supply would work. Probably need quite a few turns of
moderate size ~22AWG magnet wire. Maybe 300 turns... ugh.
Makes my hands hurt just thinking about it. I guess a bobbin
wound inductor would be better. Gapped ferrite isn't bad!

Check this site http://schmidt-walter.eit.h-da.de/smps_e/smps_e.html

I try to stay away from dumpsters but if I see anything electrical
or electronic in one it's neigh impossible.



wrote in
:

Like you said I like to Frankenstien things. I have a filter from
another power supply but I am not sure how well it will work
as it was designed for about 25 amps. Basically thats a bridge I will
jump off of when I come to it. Right now I am having enough trouble
finding an old PC power supply I can get a transformer from. Its hard
to believe about a couple of months ago I tossed about a dozen of
them. Last time I listen to my wife. I do have a couple of
transformers from some old Lambda power supplies. Thes are some really
nice ones probably capable of handling a couple of Kwatts. Im not
ready to experiment with them yet. Although this is learning by
destuction it's cautious destruction. I will probably take a trip down
to the local computer place this weekend and do a little dumpster
diving or make a run on the goodwill store and see what I can get for
$10. IF you havent figured it out by now I love building things from
others discards. When I was in high schooI I built a killer stereo, I
thought at the time, from old stuff I found in the dump that was the
envy of most of my friends. Ive enjoyed doing it ever since.

Jimmie

On Oct 9, 11:11*pm, Grumpy The Mule wrote:
Cobbling stuff together is lots of fun. *From Pressman's
book you can figure out the inductor value. *

I'm guessing a powdered iron toroid from the output of a PC
power supply would work. *Probably need quite a few turns of
moderate size ~22AWG magnet wire. *Maybe 300 turns... *ugh.
Makes my hands hurt just thinking about it. *I guess a bobbin
wound inductor would be better. *Gapped ferrite isn't bad!

Check this sitehttp://schmidt-walter.eit.h-da.de/smps_e/smps_e.html*

I try to stay away from dumpsters but if I see anything electrical
or electronic in one it's neigh impossible.

wrote :





Like you said I like to Frankenstien things. I have a filter from
another power supply but I am not sure how well it will work
as it was designed for about 25 amps. Basically thats a bridge I will
jump off of when I come to it. Right now I am having enough trouble
finding an old PC power supply I can get a transformer from. Its hard
to believe about a couple of months ago I tossed about a dozen of
them. Last time I listen to my wife. I do have a couple of
transformers from some old Lambda power supplies. Thes are some really
nice ones probably capable of handling a couple of *Kwatts. Im not
ready to experiment with them yet. Although this is learning by
destuction it's cautious destruction. I will probably take a trip down
to the local computer place this weekend and do a little dumpster
diving or make a run on the goodwill store and see what I can get for
$10. IF you havent figured it out by now I love building things from
others discards. When I was in high schooI *I built a killer stereo, I
thought at the time, from old stuff I found in the dump that was the
envy of most of my friends. Ive enjoyed doing it ever since.

Jimmie- Hide quoted text -

- Show quoted text -

From what I gather fro mthe website there is little danger in making L
to large within reason so I can expect my bits and pieces removed from
old power supplies to work. If they dont its probably because its too
small.


Jimmie

On Oct 9, 11:11*pm, Grumpy The Mule wrote:
Cobbling stuff together is lots of fun. *From Pressman's
book you can figure out the inductor value. *

I'm guessing a powdered iron toroid from the output of a PC
power supply would work. *Probably need quite a few turns of
moderate size ~22AWG magnet wire. *Maybe 300 turns... *ugh.
Makes my hands hurt just thinking about it. *I guess a bobbin
wound inductor would be better. *Gapped ferrite isn't bad!

Check this sitehttp://schmidt-walter.eit.h-da.de/smps_e/smps_e.html*

I try to stay away from dumpsters but if I see anything electrical
or electronic in one it's neigh impossible.

wrote :





Like you said I like to Frankenstien things. I have a filter from
another power supply but I am not sure how well it will work
as it was designed for about 25 amps. Basically thats a bridge I will
jump off of when I come to it. Right now I am having enough trouble
finding an old PC power supply I can get a transformer from. Its hard
to believe about a couple of months ago I tossed about a dozen of
them. Last time I listen to my wife. I do have a couple of
transformers from some old Lambda power supplies. Thes are some really
nice ones probably capable of handling a couple of *Kwatts. Im not
ready to experiment with them yet. Although this is learning by
destuction it's cautious destruction. I will probably take a trip down
to the local computer place this weekend and do a little dumpster
diving or make a run on the goodwill store and see what I can get for
$10. IF you havent figured it out by now I love building things from
others discards. When I was in high schooI *I built a killer stereo, I
thought at the time, from old stuff I found in the dump that was the
envy of most of my friends. Ive enjoyed doing it ever since.

Jimmie- Hide quoted text -

- Show quoted text -

The computer aided design was a big help. I figured 16mH. I think I
have something about that size. I have a 20mH choke at one amp that
may work.
What you think Grumpy.

Jimmie

On Oct 10, 9:34*am, wrote:
On Oct 9, 11:11*pm, Grumpy The Mule wrote:





Cobbling stuff together is lots of fun. *From Pressman's
book you can figure out the inductor value. *

I'm guessing a powdered iron toroid from the output of a PC
power supply would work. *Probably need quite a few turns of
moderate size ~22AWG magnet wire. *Maybe 300 turns... *ugh.
Makes my hands hurt just thinking about it. *I guess a bobbin
wound inductor would be better. *Gapped ferrite isn't bad!

Check this sitehttp://schmidt-walter.eit.h-da.de/smps_e/smps_e.html*

I try to stay away from dumpsters but if I see anything electrical
or electronic in one it's neigh impossible.

wrote :

Like you said I like to Frankenstien things. I have a filter from
another power supply but I am not sure how well it will work
as it was designed for about 25 amps. Basically thats a bridge I will
jump off of when I come to it. Right now I am having enough trouble
finding an old PC power supply I can get a transformer from. Its hard
to believe about a couple of months ago I tossed about a dozen of
them. Last time I listen to my wife. I do have a couple of
transformers from some old Lambda power supplies. Thes are some really
nice ones probably capable of handling a couple of *Kwatts. Im not
ready to experiment with them yet. Although this is learning by
destuction it's cautious destruction. I will probably take a trip down
to the local computer place this weekend and do a little dumpster
diving or make a run on the goodwill store and see what I can get for
$10. IF you havent figured it out by now I love building things from
others discards. When I was in high schooI *I built a killer stereo, I
thought at the time, from old stuff I found in the dump that was the
envy of most of my friends. Ive enjoyed doing it ever since.

Jimmie- Hide quoted text -

- Show quoted text -

The computer aided design was a big help. I figured 16mH. I think I
have something about that size. I have a 20mH choke at one amp that
may work.
What you think Grumpy.

Jimmie- Hide quoted text -

- Show quoted text -

This is just way to cool. I took a 500watt Lambmda 15 volt switcher I
had used to power a solidstate amp and wound another secondary on the
transformer. I lost count of the numer of turns, maybe 100, but
after filtering and rectifying im getting about 450 volts and it has
been running since about 9:30 AM 3hrs putting out 150mA.

These transformers look a little wierd They seem to be two sepated
coils fastened together on a frame. It looks like you could take the
secondary coil off and replace it if you wanted to.
Grumpy , are you familar with this.

Jimmie

That's great news! You could easily buck regulate the +15
down for a filament supply as well.

I've seen transformers with seperate primary and secondary
windings. If a company is building s standard product line
with various outputs they'll sometimes do that. Although it
usually increases the leakage inductance so that's the down
side. Sometimes the output inductor and transformer can be
combined.

I hope this goes though. I keep getting error 441 so I sent
you an email regarding your last post.



wrote in
:

This is just way to cool. I took a 500watt Lambmda 15 volt switcher I
had used to power a solidstate amp and wound another secondary on the
transformer. I lost count of the numer of turns, maybe 100, but
after filtering and rectifying im getting about 450 volts and it has
been running since about 9:30 AM 3hrs putting out 150mA.

These transformers look a little wierd They seem to be two sepated
coils fastened together on a frame. It looks like you could take the
secondary coil off and replace it if you wanted to.
Grumpy , are you familar with this.

Jimmie

On Oct 10, 1:11*am, Grumpy The Mule wrote:
I try to stay away from dumpsters but if I see anything electrical
or electronic in one it's neigh impossible. (Nay impossible?????)

..
Hi Grumpy: Nags me too!!!!!! (OK spot the pun?)

But got to go; to unload my pickup of a free load of firewood got
yesterday (couldn't say no to a second free batch in a week)!

Gee there were two old SPS supplies lying there too; probably all
soaking wet! I didn't even look at the old 14 inch TV lying there as
well in the junk pile.

Wet... well, I wouldn't pass them up!

I've salvaged a few pieces of gear from floods.
My most cherished HP RF sweep generator came out
of the mighty Mississippi river flooding in the
early 90's. First I carefully brush off the gunk
while washing with tap water. Then I flush with
DI or distilled water dry with a fan. Finally flush
with anhydrous isopropanol and dry with gentle warming.
After that a bit of lubriplate on any switch detents
or gears as needed. I take some things out first for
special treatment, like meter movements.

The distilled water flushes off the stuff we worry
about, ionic contamination and the alcohol removes
the water. At least that's what I hope for.

I'm trying to reform and not drag so much junk home.
Sometimes I can even pass up junked hardware without
flinching. With technical books of any sort I'm not
having much success resisting though.

Mmm! Free firewood. Which reminds me, I need to fill the
wood shed yet. Oak wilt disease is killing my trees but
at least I'll be warm.



terry wrote in news:01a69e21-6f4f-472a-9865-
:

.
Hi Grumpy: Nags me too!!!!!! (OK spot the pun?)

But got to go; to unload my pickup of a free load of firewood got
yesterday (couldn't say no to a second free batch in a week)!

Gee there were two old SPS supplies lying there too; probably all
soaking wet! I didn't even look at the old 14 inch TV lying there as
well in the junk pile.