I have a welder that I made from a old Hobart CyberTIG, by using aa
modern SCR firing controller by PCTI, Inc and a Cubloc microcontroller
It all seems to work, but there is a bewildering issue.
Current and voltage are regulated using potentiometers. (not
microcontroller outputs, for now)
When I have current pot set to 0, and connect work and electrode leads
to make a short, the current is not 0, but is instead about 12 amps.
I verified that output voltage from the potentiometer is zero. It is
not some sort of floating ground issue for the input of the SCR firing
board -- they all share the same ground.
So.. What could it be? Why is it outputting current when it is set to
Just as a side note, it sets voltage just fine and goes to zero volts
when the voltage pot is set to 0.
16 years ago