Tweco 400 Ultra-Cut XT Plasma Cutting System - Manual (Page 217)

ULTRA-CUT 100 XT/200 XT/300 XT/400 XT
Manual 0-5297 APPENDIX A-83
Troubleshooting:
1. Check that the input power cables are connected to the inverters.
2. Check if the contactor for that section (W1 for 1A, 1B, 2A; W2 for 2B, 3A, 3B) is energized.
a. There is a rectangular section in the middle of each contactor top that can be used to attach auxiliary con-
tacts. This can also be an indicator of contactor operation as it pulls in when the contactor is energized.
b. Check for CB2 on the rear panel being tripped. The white button marked “5” indicating it’s 5 amps, will
pop out if tripped. Reset it and if it pops out again something (contactor coil?) may be shorted.
c. Measure for 120 VAC on the contactor coil. If present, but the contactor isn’t pulled in, it’s probably a
defective contactor.
3. On the Relay board D22, CONTACTOR ON LED (green) next to relay K1 lights if K1 is being told to energize.
a. If it’s on check for 120 VAC between J8-1 and J8-9. If present the relay board is OK.
b. If D22 is on but 120 VAC is not present at J8-1 and J8-9 (make sure meter is set for ACV) then the relay
board is defective.
c. D22 is not on, go to the 40 pin ribbon cable test connector and measure voltage on pin 17 (relative to
TP1 on either the Relay board or the CCM I/O Board). It should be low, less than 1 volt. If it is the relay
board is likely bad. If it’s high, about 24VDC then the CCM may be bad, not telling the contactor to turn
on.
4. The inverter section may be defective with a bad bias supply. Swap the inverter end of the ribbon cable with
one next to it.
a. If it now reports a different code, that of the inverter that was swapped with, then the original section is
bad.
b. If it still reports the same section even though the ribbon cable was swapped then the CCM is bad.
271 Inverter ID Reading Fault.
Refer to section for codes 225-230 for a description of the ID signals. If this code appears it means one of these
ID signals has gone false some time after power up.
Possible causes:
• An intermittent ribbon cable or one not fully latched in place.
• EMI interference.
Troubleshooting:
1. First recycle power to see if the fault is still there. It may now show up as one of the 225-230 codes which
will indicate which inverter.
2. Determine when the code shows up. If it is EMI it may not happen every time but if, when it happens, it is
always at the beginning of piloting, it may be EMI interference. Check the system ground cables and if an
AC200XT check the torch shield connection to the unit rear panel.
3. If it happens intermittently during cutting or idling it might be an intermittent ribbon cable. This code does
not say which inverter section so you have to check each ribbon cable for proper connection on each end. It’s
highly unlikely for a ribbon cable to be intermittent but if you have more than 2 sections try disconnecting
one section at a time and cut at lower current. See if you find one that causes the problem and if so replace
that ribbon cable.