|
Posted by Jon Danniken on April 29, 2008, 6:20 pm
Please log in for more thread options
"Ignoramus29893" wrote:
> Jon Danniken wrote:
>
>> Before I can do that, however, I need to first determine the topology
>> that
>> is used in this type of circuit (silicon control of current in a welder).
>> I
>> am hoping I can come across an early TIG supply schematic that will give
>> me
>> clue as to what methodology was used, be it pre-transformer control or
>> post-transformer control. That's where I'm stuck at right now.
>
> The topology is that of a regular rectifier bridge (1 or 3 phase), but
> with SCR instead of diodes.
Thanks, Iggy. Digging around more it does seem to be common on some TIG
machines; I will go with this.
> The SCR drivers need to do a lot of things.
>
>>>> I wonder if there were any TIG supplies that used a more simple
>>>> method of controlling the current, maybe in the pre-IC days?
>>>
>>> Don mentioned another method. I do not recall what it is.
>>
>> IIRC, he mentioned he would use IGBTs, but I think that might be more
>> complicated than I am williing to go, at least at this stage. SCRs don't
>> seem too terribly complicated for me, it's just finding out the layout of
>> a
>> basic welder current control to give me a place to start that is my
>> obstacle
>> right now. Eventually there will be zero-crossing detectors, but one
>> step
>> at a time.
>>
>
> I have a big SCR assembly for sale. $100 plus shipping for
> Rec.Crafts.Metalworking.
>
> http://yabe.algebra.com/~ichudov/misc/ebay/Giant-Thyristor-Bridge/
You have mail.
Jon
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap
>