I have been cutting parts out of 3/8" stl plates 5' x 10'
The cuts are long roughly 46" turn then come back 46" (guardrail posts)
I was using a HyperT 1650 machine with 60 amp tip set at 141 volts.
I noticed when the torch was traveling down the long straight cuts my cut voltage
would vary from 138 up to 143 then back down to 138 back up to 143, this cycle
was very consistent and took about a second and a half to two seconds.
I have a 10HP compressor with RTI filter then a MotorGuard filter and an AirGuardian
desiccant filter at the 1650, so I think I'm getting clean dry air. Machine is
not sloppy. Does anyone have any ideas what could cause this slight oscillation?
95% of the cuts were excellent cut quality with very easy to remove dross.
I forgot to mention I was using water about 1-1/2 to 2" below the plate.

Thanks in advance,
Mike Scalise
Deep South Texas