Tweco 300 XT Auto-Cut 400V - Manual (Page 137)

AUTO-CUT 300 XT
Manual 0-5290 APPENDIX A-55
Troubleshooting:
1. If System Bias board has either the wrong jumper or is defective it will call out the first inverter section, code
231, because all the inverters won’t match the incorrect signal and 1A is checked first.
a. For the jumper Wire #48 should be connected from J61-1 to:
i. J61-2 for 208-230 VAC
ii. J61-3 for 400 VAC
iii. J61-4 for 480 VAC
Check for proper connection and continuity.
b. System Bias may be defective reporting the wrong voltage ID. On the output of the System Bias board
at J62 measure relative to TP1 or ( J62-8, 24VDC_RET) to J62-12 for signal /VAC_IDAb and J62-14 for
signal /VAC_IDBb. The 2 signals should read according to this table. “0” = 10-12V; “1” = 24V.
signal 230V �00V ��0V ERR
/VAC_IDAb 0 1 0 1
/VAC_IDBb 0 0 1 1
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 sec-
tion 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 sec-
tion. 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.