Tweco 400 XT Ultra-Cut Plasma Cutting System With Automated Gas Control - Manual (Page 186)

ULTRA-CUT 400 XT
A-62 APPENDIX Manual 0-5306
2. Defective inverter, ribbon cable or CCM.
a. On the inverter section swap the ribbon cable of the inverter section whose fault was indicated with that of a different
inverter section. If fault remains unchanged, still calls out the original inverter section, the problem is with either
ribbon cable or CCM. If fault changes to the different section, the one the ribbon cable was swapped with, 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 cable with another one on the CCM. If the fault now moves to a different section it’s the
ribbon cable. If it remains with the original section the problem is the CCM.
237 Too Few Inverters Found
There must be a minimum of 2 inverter sections present to operate. We know the ribbon cable for inverter section 1A is
connected or else we would have code 224. During the power up sequence, before power is connected to the inverters, the
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 224 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 231-236 for details. If one of the 3 voltage ranges, 208-230V, 380-415V or 480V 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 231-236 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 J62 and J27.