| 摘要 |
Protective device in plasma welding and cutting equipment in order to, in the event of a short circuit between the electrode (E) and the plasma nozzle (D), prevent the burner from charging a prohibited voltage. The equipment comprises a voltage feeder source and a pulse ignition tool in a series with this connected between the electrode (E) and the working piece (A), at which a part of the voltage source by means of a resistor (R) is connected between the electrode (E) and the plasma nozzle (D). Between the plasma nozzle (D) and the resistor (R) a voltage sensing device (RL2) is connected, which contact device is arranged to disconnect the voltage source. Above the voltage sensing device (RL2) and a part of the resistor (R) a fuse device is connected (S), which with an unimpaired fuse short circuits the voltage sensing device and such a large part of the resistor (R) that the plasma nozzle (D) charges to a sufficient pilot arc voltage.<IMAGE> |
