Tweco 400 XT Ultra-Cut Plasma Cutting System With Automated Gas Control - Manual (Page 178)

ULTRA-CUT 400 XT
A-54 APPENDIX Manual 0-5306
105 Not Used. This is one of the reserved codes from the earlier product.
106 Pilot Timeout, no Transfer
Pilot time is limited to either 0.085 seconds (85 ms.) with CCM SW8-1 off (default for pierce starting) or 3 seconds with
SW8-1 on (used for cutting over holes, expanded metal, etc.). Arc must transfer before pilot time ends. Code 106 is set
if no arc transfer (current in work lead) was sensed before pilot timed out. If the unit does not detect pilot current the arc
starter will operate up to 15 seconds then set the 102 code. If you are getting 106 there is pilot current somewhere. If it’s
not visible perhaps it’s inside the consumables or following some other part.
Causes for 106 code:
No Pilot Visible:
• Pilot inside the consumables
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 consumables.
• 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 starting level and
pilot timer (85 ms. or 3 sec) will time out.
107 Not Used. This is one of the reserved codes from the earlier product.
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 determined 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.
Causes for 108 code:
• Gas Flow/pressure too low for consumable parts being used.
o If gas source pressure is not well regulated it is possible pressure may be OK at times and drop too low at other
times such as during a cut.
o A leak of the preflow/plasma gas after the pressure/flow control (GCM 2010, DPC, GCM 1000 XT) can reduce the
pressure/flow to the torch because some if it is bypassing the torch, while seeming to have enough pressure/flow
at the gas control.