Thermal Dynamics Ultra-Cut 300 XT, Operating Instructions Manual

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ULTRA-CUT 400 XT
Manual 0-5275 APPENDIX A-55
Visible Pilot:
• First the obvious, make sure the work lead is connected both to the work and the power supply. Also
make sure the work itself is making good electrical contact with cutting table. If rusty or painted metal,
you may need to clean a spot and attach the work lead directly to the metal.
• Torch too far from work.
• Cut current set too low for torch parts being used. Pilot current is set based on cut current. If cut current
is too low pilot current will be lower and may not transfer at the height used for higher current consum-
ables.
• Preflow pressure/flow too low.
• Remote Analog Current Control switches set wrong can also result in lower than normal pilot current
setting. See section on these switch settings under section for code 104.
• Defective work lead current sensor circuit. If transfer is not sensed cut current remains at the lower start -
ing level and pilot timer (85 ms. or 3 sec) will time out.
107 Tip saver fault for Pak200i only.
Torches with exposed tips can be damaged if the tip touches the work while cutting. Tip saver reduces the cur-
rent to a level that the tip can handle for a while. Fault occurs with the Pak200i torch if the tip has contacted
the work longer than 15 seconds. The 1Torch with the current reduced by the tip saver circuit is not limited in
the time it can touch the work.
108 Tip to Electrode Voltage Fault
The Pilot voltage, measured between tip and electrode varies with different current and gas type, flow rate and
consumable design.
Once the arc is transferred the pilot switch opens leaving the tip basically floating. The voltage then is deter-
mined by how much of a cold gas barrier surrounds the arc. Too much current or too little gas and the arc
starts to contact the tip reducing the voltage difference between tip and electrode and leading to a double arc
that destroys the consumables.
The CCM measures both electrode and tip voltage and calculates the difference. If the difference between tip
and electrode is found to be less than a minimum voltage we stop cutting and set a fault for the 108 code. The
normal tip to electrode voltage is different for different processes so the min value for each process is embedded
in the cut charts when using the DFC 3000 or in the CCM code if using the GCM 2010 or for Auto-Cut XT gas
controls (GCM 1000XT or the built in one in the AC 200 XT).
New for the Auto-Cut XT units is a switch on the rear of the power supply that needs to be set according to the
plasma gas. If using an oxidizing gas (O2 or Air) set it as indicated for those gasses (left if AC 200 XT or up for
AC300XT) or if using a non-oxidizing gas (N2, H35 or other inert gas) set it to the right or down as indicated for
those gas types.. This switch adjusts the range of voltage for the gas type to better protect the torch. A wrong
setting could result in false setting of the 108 code.
During piloting and ramping (the time from transfer until the current reaches full cut current), we lower the
allowed tip to electrode voltage to about 80% of that allowed during cutting because the current is lower and
the gas flow is lower during that time.