Tweco 400 XT Ultra-Cut Plasma Cutting System - Manual (Page 169)

ULTRA-CUT 400 XT
Manual 0-5275 APPENDIX A-�1
CCM does a continuity test through the ribbon cable to see if an inverter is connected. If it doesn’t see continuity with at
least one other inverter it assumes none are connected.
Possible causes:
• Ribbon cable disconnected or defective.
• Inverter defective
• CCM defective.
Troubleshooting:
1. Check that all cables are connected, latches locked down, at both the inverter and CCM ends.
2. If this fault occurs it’s most likely on a 100A unit which only has one section (1B) in addition to the 1A section. If there
were 2 or more additional sections it’s extremely unlikely all ribbon cables or CCM connectors would be defective.
a. Swap the ribbon cables of the inverter section 1A and 1B. If fault remains unchanged, still 237, problem is with either
ribbon cable or the CCM. If fault changes from 237 to 22� indicating inverter 1A missing, then it’s the inverter that’s
defective.
b. If the fault remained unchanged in step a., on the inverter end put the ribbon cables back in their original positions.
Now swap suspect ribbon cables on the CCM. If the fault now changes it’s the ribbon cable. If it remains the same
it is the CCM.
c. If there are 2 or more ribbon cables in addition to the one on section 1A then CCM is seeing none of them connected
which indicates the CCM is faulty.
238 System Bias voltage identification is invalid.
At power up the System Bias board measures the input voltage and sends signals to the CCM indicating which range of
voltage it has detected. See section 231-23� for details. If one of the 3 voltage ranges, 20�-230V, 3�0-�15V or ��0V isn’t
identified then both ID signals are high resulting in an invalid signal.
Possible causes:
• Unit is connected to voltage below the 208-230V range or above the 480V range. (unlikely unless there is a problem
with the incoming voltage.)
• Defective System Bias board
• Bad connection between System Bias output J62 and CCM input J27 on the I/O board.
• Defective CCM
Troubleshooting:
1. Measure all 3 phases of the input voltage and confirm they are within the tolerance specified in the unit manual.
2. Refer to section 231-23� Inverter VAC Mismatch and perform troubleshooting in step 1.b. If the 2 signals don’t match
the incoming voltage, if both are high, then the System Bias is defective.
3. If step 2 was OK make the same measurement at J27 on the CCM I/O PCB. If OK here the CCM is defective. Otherwise
inspect the connections at J�2 and J27.
239 AC Voltage High
Voltage OK -- At power up the System Bias board measures the input voltage and determined if it is within the range of volt-
age set by the J1� jumper. See section 231-23� Inverter VAC Mismatch Troubleshooting step 1.a for details of the jumper.
Normally when the input voltage is OK the System Bias board turns on a relay K1 on the left die of the board to apply power
to the T1 Auxiliary transformer. D��, a green “Transformer ON” LED, will light when K1 is energized. T1 provides power to
the gas controls and the TSC 3000 as well as the pumps and fans.
Voltage High -- If the AC voltage is determined to be too high it lights D�, ACV HIGH, a red LED on the System Bias board,
and sets the signal “AC V HIGH b” on J�2-� to a “high” about 2�VDC (normal for a “low” here is 10-1�VDC). To prevent
the possibility of excessive voltage applied to several items (gas controls, pumps, fans etc.) K1 is opened removing power
from T1 and D�� goes off. If it’s more than a momentary glitch the gas controls and the TSC 3000 (if used) will reset. Com-
munication with the cutting table may be interrupted. With the DFC 3000 Auto Gas Control and perhaps the cutting table
control, the process will have to be reloaded.