Abstract: A plasma arc torch has a threadless electrode-cathode locking assembly, a one-piece tip assembly, and a rotational contact starting mechanism. The cathode and electrode of the locking assembly are configured such that relative rotation of the electrode with respect to the cathode causes the electrode to move in an axial direction relative to the cathode for locking the electrode in fixed axial and rotational position with respect to the cathode. The inner wall of the one-piece tip assembly is configured to receive the forward end of the electrode in a non-contact position. Rotation of the electrode with respect to the tip causes an arcing formation on the electrode to contact an arcing chamber within the cavity. Rotation of the electrode away from the tip generatesa pilot arc in the arcing chamber.

Abstract: Plasma arc torches are provided that include a mounting for an electrode and a coolant tube telescopingly mounted on the plasma arc torch to engage and deliver coolant to electrodes of different sizes mounted in the mounting. The telescopingly mounted coolant tube may extend to a closed position in which coolant does not flow when no electrode is mounted in the mounting. The telescopingly mounted coolant tube may further be used to electrically connect a cathodic member with the electrode mounted in the mounting.

Abstract: A plasma arc torch system, a circuit, and a method for controlling a pilot arc is disclosed. A rate of change sensor, such as a dv/dt sensor, monitors an output current signal or an output voltage signal to determine whether to close a switch to re-attach a pilot arc before a transferred arc becomes extinguished. The switch selectively connects a tip into a circuit path with an electrode and a power supply to allow the pilot arc to form between the tip and the electrode. A power supply preferably regulates the output current or voltage to a first level when a pilot arc is present, and to a second mode when a transferred arc is present.

Abstract: A tip gas distributor is provided that preferably comprises a plurality of swirl holes and a plurality of secondary gas holes, wherein the swirl holes direct a plasma gas to generate a plasma stream, and the secondary gas holes direct a secondary gas to stabilize the plasma stream. Additionally, a tip gas distributor is provided that comprises swirl passages and secondary gas passages formed between the tip gas distributor and an adjacent component to generate and stabilize the plasma stream. Further, methods of generating and stabilizing the plasma stream are provided through the use of the swirl holes and passages, along with the secondary gas holes and passages.

Abstract: A tamper resistant pin connection for use in a plasma arc cutting apparatus is provided that comprises a plurality of locking fingers within a hollow internal channel of a housing that secure a negative lead gas carrying pin within the housing. The pin comprises a first collar with a shoulder disposed thereon, and accordingly, the locking fingers engage the shoulder to secure the pin within the housing. The pin further comprises a second collar that blocks access to the locking fingers through a first portion of the hollow internal channel such that the locking fingers cannot be accessed to disengage the pin. Further, the pin is recessed within a second portion of the hollow internal channel to prevent further access to the pin for a tamper resistant pin connection.