i have some questions about tig welder control circuits, hope some one can help.
in a tig welder you set a maximum amperage for the output then use the foot pedal to control the amperage within that range. how does the circuit work or what is the name for that type of circuit?
can anyone please point me to a circuit or explain how to build a circuit to do this?
Go to the Miller welding site and check the service manual for one of its TIG welders. You may need to register. Miller provides the schematics for most of its welders. John
I have a Miller Dialarc HF, circa 1983, number 901-782 ( I think). If you are interested in something with that old technology, I will drop by the shop and get you a serial number.
John
Edit: The circuit diagram will be just that. It will not describe how it works. You will have to figure that out from the diagram.
I have a Miller Dialarc HF, circa 1983, number 901-782 ( I think). If you are interested in something with that old technology, I will drop by the shop and get you a serial number.
John
Edit: The circuit diagram will be just that. It will not describe how it works. You will have to figure that out from the diagram.
It is actually a Dialarc HF-P, s/n JD709609. Sorry, my mind is getting weak, I forgot the -P in the model number. I bought it new in 1983 or 1984.
It is a great welder and has not given me a single moment of concern. The foot control may not be linked to that s/n, but there really is not much to the foot control. Never had it apart, but assumed it was just rheostat or something similar. There are not a lot of electronics with this machine.
ok, the amp control seems to be a set of AC coils with a DC coil with varying voltage from the foot pedal, all on a transformer core. here is the pdf of the manual: https://www.electro-tech-online.com/custompdfs/2009/09/o315j_mil.pdf page 4 is the schematic.
in the parts list they call this a "magnetic amplifier"
don't know quite how it works. DC clamping part of the AC current is my guess?
I had forgotten what a magnetic amp is, so I had to look it up. You're on the right track. The DC current changes the characteristics of the amplifier's core, which in turn effects the B-H curve on the material ( are you familiar with B-H curves? ) In that way, the DC current controls the amount of AC current tranfered. It's a complicated curcuit to analyze. That's one reason they are so expensive, I'm sure