Need some electronics help converting my Mig welder to gas?

D

davegt27

Well-known member
I have a Lincoln pro core 125 that I bought at Lowes a few years ago (I did ask to make sure it could be converted)

I had been slowly buying the parts to convert it to Gas well it turns out my over $400 flux core welder can’t be converted (I mean it had everything but the connections on the circuit board and the gas solenoid)

Not easily anyway
Anyway I figured a relay and a few connections would do the trick

I figured a relay that operated off the gun could energize a relay and turn on the gas solenoid that I mounted in the welder


I read 15V dc at the trigger but when I hook up a relay the circuit sees it as a short (closed gun trigger switch) and as soon as I turn the welder on it thinks the trigger is being pulled

I hooked up a variable resistor in series with the relay and I need 3.37K for the circuit not to see a short (or think the trigger is being pulled)

The welder uses a floating ground inside and the circuit board is partially potted with silicon

Any ideas on how to actuate the gas solenoid


Thanks in advance
David
 
With the major caveat that I'm an ME not an EE -

Were you using a mechanical relay? I wonder if a solid state relay would draw sufficiently little control current so as not to activate things? Maybe using a series resistor?

Also - I wonder if you could connect the relay activation to the other side of the switch?

Al Seim
 
Al Seim":1o0hfegv said:
With the major caveat that I'm an ME not an EE -

Were you using a mechanical relay? I wonder if a solid state relay would draw sufficiently little control current so as not to activate things? Maybe using a series resistor?

Also - I wonder if you could connect the relay activation to the other side of the switch?

Al Seim
Click to expand...

I started off with a common automotive relay but I went to Radio Shack and picked up low current relay
But that did not work (putting 3.3K on the low side did not work either)

Joe:
https://www.youtube.com/watch?v=xjPLTpl04j0

That’s the information I had been using I unfortunately bought everything first and all I had to do is make the final connection on the board

Well there are no unused connections or any wires labeled Solenoid

Now when I monitor the voltage I get +15V when I hit the trigger it drops to zero

David
 
Ok I think I got it, took some praying

But It came to me there is already a relay on the circuit board has to be there for a reason

Long story short I pulled the connection off the relay put a splitter (single female to dual males) this goes to one side of the AC solenoid the other side of the solenoid goes to input (another splitter) into the welder.

Turned it on pulled the trigger and all works
Put my finger on the solenoid and it works when I pull the trigger

I just need to button it up and do the final ops check
Davegt27
 
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