Re: went from a hand held torch to a machine torch Herpertherm 45 to a 85. Plasmacam
The design of that ohmic sensing ring is bad. You should either replace it with a new one, or you can TRY to bend the tab down to make contact with the shield.
One of my clients who hired me to train him on how to use the DesignEdge software for his PlasmaCam table did the "one Cent Fix." He slipped a copper penny between the tab and the shield, and the contact was made.
You can alternately wrap a hose clamp around it and use the clamp to pinch the tab to pull it in to contact the shield. Some people use a solid copper wire or even a copper oil drain plug washer and slip it between the tab and the shield.
Honestly, it is a BAD design. The tab MAY contact the shield when it is cool, but after cutting, it gets hot so it bends out from HEAT like a thermostat, and then bends back to re-establish contact when it cools again.
MOST of the height control sensing issues on a PlasmaCam table can be traced to that failed contact between the ohmic sensing tab and the torch shield.