http://www.youtube.com/watch?v=h5JN0rPoadQ

With this link you can see a video of the flickering pilot arc

On our welding machine using plasma welding process, unstable pilot arc behavior occurred. In a difficult to be determined time and condition the pilot arc starts to “flicker” .It can happen directly after starting the arc, after some time (2 – 3 hours) of arc burning or just after using higher ampe...