Tweco 100 Ultra-Cut Plasma Cutting System with Automated Gas Control - Manual (Page 182)

ULTRA-CUT 100 XT
A-58 APPENDIX Manual 0-5303
202-204 Not used. Reserved codes from the earlier product.
205 DC Output Low
DC output (voltage) low means one or more inverter sections are enabled but the output voltage is below a
preset voltage. Shortly after receiving the Start signal from the CNC, but before the end of preflow, both sections
of IM#1 are enabled and CCM measures the power supply output voltage between negative (Torch) to positive
(Work) at the output terminals. If this is less than a set value during preflow or if at any time during piloting
or cutting it drops to below that value for a short time, the inverters are shut off and code 205 is set. 205 will
almost always be indicated as an “L”, not an “E” fault because as soon as it’s detected the inverters are shut off
and so no longer have the fault of low output voltage. Currently the low voltage value is -�0VDC.
Causes of 205 code can include shorts outside the plasma power supply, shorts inside the plasma power supply
and measurement errors.
a. Short external to the plasma power supply:
• The negative lead goes from the rear of the power supply to the remote arc starter or to the GCM 1000 XT
in the case of the AC 3000 XT.
o Cable pinched in or exiting the power track
o Short inside the Arc Starter such as a wire coming loose and grounding to the chassis.
o Short inside the torch mounting tube.
• Trouble shoot for external negative lead shorts by removing the lead from the rear of the power supply
and try to start. It won’t start but if you get the same 205 code the problem is inside the unit.
b. Short inside the supply:
• All the inverters outputs except that of IM1A are in parallel. If any inverter’s output is shorted it will
appear as a short across the power supply output.
Troubleshoot by removing all (or one at a time) of the inverter output connectors except those on IM1A.
Then apply Start to the unit. If it starts now one of the other inverters had shorted output. To find
the defective one reconnect one at a time until the fault reappears.
206 Not used. Reserved codes from the earlier product.
207 Unexpected Current in the Work Lead.
HCT1, a Hall Effect current sensor on the positive (work buss bar) measures the work lead current. Inverter
section 1A is enabled during preflow time but there should be no current in the work lead before the pilot is
ignited and before the arc is transferred to the work. If current greater than �A is detected before or during
preflow something is wrong.
1. 207 code before START applied:
• Defective work current sensor, HCT1.
• Defective Relay PCB
• Defective CCM
Defective Sensor
• The work current sensor, HCT1, receives power, +15VDC and -15VDC from the Relay PCB. Both must
be present for the sensor to work properly. Measure between Relay PCB TP1 (or J1-�) to J1-1 for +15VDC
and to J1-2 for -15VDC.
• If either + or – 15VDC not present remove the J1 connector and repeat the measurement at J1-1 & 2 on the
Relay board. If the voltage is now present the sensor is defective or shorted (the harness may be shorted).
If voltages still not present, the Relay board is defective.