Hey Iggy,

I am in the process of converting my buzzbox to something resembling a 150A
TIG supply. I already have the AC-DC section figured out, as well as the HF
area.

I believe you used SCRs in a circuit you used to control the output current
of one of your machines, and I am very interested in this. Do you by any
chance have a schematic of this section of your circuit, and/or any other
reference schematics of going about this topology for a high current supply?

Thanks for your help,

Jon

On 2008-04-28, Jon Danniken wrote:
Hey Iggy,

I am in the process of converting my buzzbox to something resembling a 150A
TIG supply. I already have the AC-DC section figured out, as well as the HF
area.

What is your OCV?

I believe you used SCRs in a circuit you used to control the output
current of one of your machines, and I am very interested in this.
Do you by any chance have a schematic of this section of your
circuit, and/or any other reference schematics of going about this
topology for a high current supply?


Jon, I have some documentation along with parts pictures, sample
welds, etc, he

http://igor.chudov.com/projects/Weld...New-Rectifier/

If your welder is single phase (mine is 3 phase), it changes a lot due
to ripple.

All together, this was a moderately expensive project and I would be
better off just buying a nice welder. It was fun, but very time
consuming.

I also post the source code of my welder, written in BASIC, he

http://igor.chudov.com/projects/Weld...ier/source.txt

It is under GPL, so feel free to do whatever you want with it, as long
as you keep it free software.

i

"Ignoramus18948" wrote:
, Jon Danniken wrote:
Hey Iggy,

I am in the process of converting my buzzbox to something resembling a
150A
TIG supply. I already have the AC-DC section figured out, as well as the
HF
area.

What is your OCV?

80V on the low range, for AC. I'll probably lose a bit after it goes
through the bridge.

I believe you used SCRs in a circuit you used to control the output
current of one of your machines, and I am very interested in this.
Do you by any chance have a schematic of this section of your
circuit, and/or any other reference schematics of going about this
topology for a high current supply?


Jon, I have some documentation along with parts pictures, sample
welds, etc, he

http://igor.chudov.com/projects/Weld...New-Rectifier/

If your welder is single phase (mine is 3 phase), it changes a lot due
to ripple.

All together, this was a moderately expensive project and I would be
better off just buying a nice welder. It was fun, but very time
consuming.

I also post the source code of my welder, written in BASIC, he

http://igor.chudov.com/projects/Weld...ier/source.txt

It is under GPL, so feel free to do whatever you want with it, as long
as you keep it free software.

Sure, thanks Iggy. I forgot yours was a three phase sysem, which does shift
things around a bit. I'll look through the page you provided, that looks
like a good place to start.

Thanks,

Jon

On 2008-04-28, Jon Danniken wrote:
"Ignoramus18948" wrote:
, Jon Danniken wrote:
Hey Iggy,

I am in the process of converting my buzzbox to something resembling a
150A
TIG supply. I already have the AC-DC section figured out, as well as the
HF
area.

What is your OCV?

80V on the low range, for AC. I'll probably lose a bit after it goes
through the bridge.

I believe you used SCRs in a circuit you used to control the output
current of one of your machines, and I am very interested in this.
Do you by any chance have a schematic of this section of your
circuit, and/or any other reference schematics of going about this
topology for a high current supply?


Jon, I have some documentation along with parts pictures, sample
welds, etc, he

http://igor.chudov.com/projects/Weld...New-Rectifier/

If your welder is single phase (mine is 3 phase), it changes a lot due
to ripple.

All together, this was a moderately expensive project and I would be
better off just buying a nice welder. It was fun, but very time
consuming.

I also post the source code of my welder, written in BASIC, he

http://igor.chudov.com/projects/Weld...ier/source.txt

It is under GPL, so feel free to do whatever you want with it, as long
as you keep it free software.

Sure, thanks Iggy. I forgot yours was a three phase sysem, which does shift
things around a bit. I'll look through the page you provided, that looks
like a good place to start.


Another point is, SCR driver boards are expensive. I was very lucky in
that for some readon, PCTI liked my kids site algebra.com so much that
they donated a SCR driver device to me, which was easy to use.

Still, I would be far better off applying my efforts elsewhere,
wotking less hours, and buying a great new welder. That said, I
learned something.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
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"Ignoramus18948" wrote:
Another point is, SCR driver boards are expensive. I was very lucky in
that for some readon, PCTI liked my kids site algebra.com so much that
they donated a SCR driver device to me, which was easy to use.

Still, I would be far better off applying my efforts elsewhere,
wotking less hours, and buying a great new welder. That said, I
learned something.

Those are some good points you make there. I guess what I am trying to do
is use a handfull of discrete componenets to make as simple of a
variable-current supply as I can get away with. Perhaps the only way to
control the current is with a highly-advanced topology, utilizing complex
circuit boards, but if there is a way to do it with a minimum of components,
then I am going to try to do this.

I guess what I really need is to look at a schematic of a transformer-based
TIG supply that used SCRs to control the output current, and see how they
did it there, but I don't know the name of any units that used such a
control method, much less have a schematic.

Jon

On 2008-04-29, Jon Danniken wrote:
"Ignoramus18948" wrote:
Another point is, SCR driver boards are expensive. I was very lucky in
that for some readon, PCTI liked my kids site algebra.com so much that
they donated a SCR driver device to me, which was easy to use.

Still, I would be far better off applying my efforts elsewhere,
wotking less hours, and buying a great new welder. That said, I
learned something.

Those are some good points you make there. I guess what I am trying to do
is use a handfull of discrete componenets to make as simple of a
variable-current supply as I can get away with. Perhaps the only way to
control the current is with a highly-advanced topology, utilizing complex
circuit boards, but if there is a way to do it with a minimum of components,
then I am going to try to do this.

I guess what I really need is to look at a schematic of a transformer-based
TIG supply that used SCRs to control the output current, and see how they
did it there, but I don't know the name of any units that used such a
control method, much less have a schematic.


Look at the manual of Miller Syncrowave 250. I believe that it
includes an intelligible schematic and uses SCRs.

--
Due to extreme spam originating from Google Groups, and their inattention
to spammers, I and many others block all articles originating
from Google Groups. If you want your postings to be seen by
more readers you will need to find a different means of
posting on Usenet.
http://improve-usenet.org/