Tweco 400 XT Ultra-Cut Plasma Cutting System With Automated Gas Control - Manual (Page 183)

ULTRA-CUT 400 XT
Manual 0-5306 APPENDIX A-59
Possible causes are:
• Short between electrode and tip due to mismatch of consumables, damaged consumables or foreign matter between
tip and electrode. An electrode at the end of its life may lose material that can short between electrode and tip.
• Defective or incorrectly installed user supplied equipment such as torch height controls that make connections to
power supply output.
• Short between power supply negative output cable and pilot cable.
• Shorted torch body.
Troubleshooting:
1. Remove and insulate (may have voltage on it) the pilot cable from the rear of the unit. Attempt to pilot. If no 208 code
shows, it confirms problem is outside the power supply.
2. Remove and check consumable for damage, cleanliness and missing (gas dist, etc.) or wrong components.
3. Disconnect user supplied equipment and see if fault still exists.
4. Inspect Arc Starter for broken/disconnected wires or burnt components.
5. Inspect inside the torch mounting tube for shorts.
6. If all else fails disconnect the pilot wire from the back of the torch head. Insulate it well or keep it away from any metal,
it may have HF (high frequency) on it when you try to start. Try to start, if the 208 is gone now the torch head is shorted.
209 Not used. Reserved codes from the earlier product.
210–211 Output current, measured by the work lead current sensor, is too high (210) or too low (211).
These are warnings and do not shut down the process but may explain poor cut quality or poor parts life.
Individual inverter sections have their own current sensors and the work lead has a current sensor whose signal should equal
the sum of the individual inverter sections. Each section is set to output a certain current based on its ”demand” signal. If
the current differs from the total “demand”, sum of the individual demands, the individual sections are checked to determine
if their output is correct compared with their demand signals.
If the individual sections are correct but the work current sensor signal differs from the total demand by more than 16% code
210 (too high) or 211 (too low) is displayed.
If an individual inverter section was found to be in error causing the total current to be wrong, a different code would be
displayed in the range of 212 to 223 depending on which section was at fault.
Possible causes for work current signal too high:
• HCT1 Work Current Sensor
• Relay PCB
• CCM
Possible cause for work current to low.
• All the above plus a short to chassis caused by:
o User installed equipment connect behind the current sensor that makes a connection to work or earth allowing
current flow to bypass work sensor.
o Inverter + output shorted to chassis.
Troubleshooting:
1. For current too low due to a short disconnect work lead from back of unit. Check for continuity to chassis, there should
be none. Inspect for incorrectly connected user equipment.
2. If no shorts were found or if fault was current signal too high see section on code 207 for detailed description of the
power and signal paths for the work lead current sensor.