Tweco 400 XT Ultra-Cut Plasma Cutting System - Manual (Page 173)

ULTRA-CUT 400 XT
Manual 0-5275 APPENDIX A-�5
• TS2, Ambient temperature sensor, shorted (very unlikely) or otherwise defective.
• Defective Relay board.
• Defective CCM.
• Defective Relay board.
Troubleshooting:
1. If room temperature exceeds �0 deg C, cool the room, or operate the unit at reduced duty cycle or lower current.
2. Confirm that air is exhausting from opening in the right side panel. As the fan(s) are behind the radiator it’s hard to see
them to confirm they are turning but perhaps you can use an inspection mirror. Be careful not to get the mirror or your
hands into the blades. 100 & 200A units have 2 smaller fans, 300 & �00A have one larger one.
3. It is unlikely these high ambient temperature codes would be set before some other temperature related code but just in
case we’ll note that leaving the side panels and cover off, especially the left lower side or the top cover will reduce the air
flow. Also the radiator fins clogged with dust will reduce air.
�. To test TS2 remove J2 from the Relay board and measure the resistance between pins � & � of the J2 harness connector.
The resistance varies from about 33K ohms at 0 degrees C to about 12K ohms at 20C to 5.3K ohms at �0C.
5. If TS2 is within the correct range the problem may be with the Relay board or the CCM.
a. The output from the relay board going to the CCM is on pin 30 of the �0 pin ribbon cable (J� of Relay board to J23
of the CCM I/O board). It is an analog voltage that should range between 0.��V at 0 deg C to 1.�V at �0C. If it is
confirmed that the room ambient is not above �0C and Ambient temperature signal at pin 30 is higher than 1.�V then
the Relay board is defective.
b. If Ambient temperature signal at pin 30 is OK, less than 1.�V, and the room ambient is not above �0C then the CCM
is bad.
265-270 Inverter No Input Power
There are several digital signals on the ribbon cables between the inverter sections and the CCM that involve some level of
voltage. These include AC_INPUT_FLT\, INVERTER _FLT\, OVERTEMP_FLT\ and POWER_PRESENT. Normally all of these
should be high. Before power is applied to the inverter modules the CCM has already performed a continuity check to see if
that section is in place and it’s ribbon cable connected (code 22� & 237). As soon as power is applied to the inverter modules
the CCM checks these � signals and, having already confirmed there is an inverter whose ribbon cable is connected. If it
finds none of the signals have voltage, it assumes there is no power into the section or something is wrong with that inverter
section’s bias power.
Possible causes:
• The 3 input phases, J103-105 to that inverter section not connected.
• The circuit breaker CB2 providing the 120 VAC to the contactor (and Remote Arc Starter) has tripped.
• The contactor powering that section (and others) defective.
• Relay board defective.
• Inverter defective.
• CCM defective.
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 contacts. 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.