Do a test for continuity between the nozzle and workpiece

This test helps to find faulty connections or damage in the pilot-arc circuit. This test will do a check of the pilot-arc cable in the torch lead but not of the conductivity of the nozzle.

Safety consideration for the XPR460

For this procedure, make sure that you use the pilot-arc relay, NOT the cooler-power relay. When at least one remote on-off switch is set to OFF (disabled), 220 VAC electric power stays ON (active) to the input side of the cooler-power relay.
Plasma power supply image that shows the pilot-arc relay and the cooler-power relay.
1 Pilot-arc relay
2 Cooler-power relay

Corrective action

  1. Remove the power from the cutting system.
  2. Locate the start-circuit assembly (PCB 4 in the plasma power supply).
    Diagram that shows the location of the start-circuit assembly Printed Circuit Board in the cutting system.
  3. Install a temporary jumper wire between J5 (nozzle) and J1 (work) on the start circuit PCB (PCB 4 in the plasma power supply).

    If you do not have a jumper wire, you can put plugs in the J7 and J8 connectors instead.

    Diagram that shows the locations of J5 (nozzle) and J1 (work) on start circuit PCB 4.
  4. Find the pilot-arc relay (CR 1), and remove the dust cover.
    Diagram that shows the location of the pilot arc relay (CR 1) with the dust cover removed.
  5. Have a second person close (push in) the contact on the pilot arc relay.
    Diagram that shows where to push in the contact on the pilot arc relay.
  6. Measure the ohms (Ω) between the nozzle and the workpiece.
    Less than 3 ohms (Ω) is good. A value more than 3 ohms (Ω) identifies a faulty connection between one of the following:
    • The torch and the ignition console
    • The ignition console and the plasma power supply
    • The plasma power supply work cable and the workpiece
  7. Examine the work cable, and replace the cable if you find damage or excess wear.
  8. Examine the pilot-arc circuit between these connection points:
    • From the plasma power supply to the gas connect console
    • From the gas connect console to the TorchConnect™ console
    • From the TorchConnect console to the torch receptacle
  9. Does the pilot-arc circuit have damage? OptionDescription
    If yes... Replace the pilot-arc cables that have damage.
    If no... Replace the torch and torch receptacle.
  10. Release the pilot-arc relay, and measure the ohms (Ω) between the nozzle and workpiece.
    The acceptable range is 9,000 ohms (Ω) – 11,000 ohms (Ω). If the ohms (Ω) value is low – approximately 5,000 ohms (Ω) or less – examine the pilot-arc circuit between these connection points. Look for insulation damage and short circuits to ground:
    • From the plasma power supply to the gas connect console
    • From the gas connect console to the TorchConnect console
    • From the TorchConnect console to the torch receptacle