Hello,
I work as a technician in a tubing mill. Unfortunately there are some occasions when the tube will "bend" or "buckle" in the mill causing it "shoot out" of the stands. This is extremely dangerous.
To minimize the danger, we install limit switches to to trip if the tube bends. The problem with this is it is difficult to tell which direction the tube will bend, and it is possible for the tube to actually destroy the limits without actually tripping them.
Someone came up with the idea to wire a 24 volt transformer-
wire the hot to a 24 volt control relay coil. Ground the neutral side of the xformer and run the neutral wire from the coil to a piece of copper tubing which will "wrap" around the tube.
When the tube bends, this will energize the relay and we can trigger an e-stop.
I like the idea but... I think it's dangerous and it goes against everything I've learned.
To me we have an UNINSULATED ENERGIZED CONDUCTOR mounted at chest level for the operators to adjust.
We are using the grounded nuetral and the equipment grounding neutral interchangeably. It just seems wrong to me on a lot of different levels.
Everyone is looking at me like I'm over-reacting and saying "it's just 24 volts."
I think they are all crazy.
I respect them, and everything else in the plant is done safely, it just seems this one circuit seems to be eluding everyone elses concern.
I don't mind over-reacting to electrical safety, so if I am... good.
But I would also like some feedback or ideas.
Last edited by pauluk; 02/08/08 07:21 AM. Reason: Removed duplicate post
