i've been googling my way through a problem and now i am stuck and haven't found an answer.
So here is what I am trying to do. i have 24vdc connected to the positive side of the coil on a relay and the negative side of the coil connected to the positive side which is connected to the tungsten on a tig welder. when the tungsten touches the part (which is grounded), the coil energizes and the contacts close. All of this happens while the welder is on but not welding. In theory this should work.
The problem i am having though is that when the welder is on, touching both the tungsten and the part energized the relay. but when the welder is off, only the negative side energizes the coil as expected. the negative on the welder is connected to the same potential as the negative of the 24vdc supply.
the strange thing is that when the welder is on and the negative end of the coil touches the tungsten, there seems to be continuity between the tungsten and the part even though they are not physically connected.
I am sorry if this not the right audience to ask but i have tried many solution with no success. I even went to my circuits professor and he couldn't figure it out.
Any help is appreciated.
ps: I have tried both mechanical and solid state relay