Tweco 400 XT Ultra-Cut Plasma Cutting System - Manual (Page 168)

ULTRA-CUT 400 XT
A-�0 APPENDIX Manual 0-5275
231-236 Inverter VAC Mismatch.
Different inverter modules are manufactured for ��0VAC, 3�0-�15VAC & 20�-230VAC operation voltages. There is a key,
called inverter ID, read through the inverter’s ribbon cable, to identify which voltage range the inverter is designed for. The
unit itself is wired differently for the different input voltages and part of that includes a jumper at J�1 on the System Bias
board that indicates to the System Bias board what voltage the unit is wired to accept.
At power on, the System Bias board measures the incoming voltage, determines what input voltage range it fall into and
sends that range information to the CCM. Before Appling power to the inverters by turning on the input contactors, the CCM
checks that each connected inverter is of the correct voltage matching that of the System Bias board. The inverter ID’s are
read from the lowest section to the highest so in all cases if it truly is a wrong voltage inverter it should call out the A section
whose code is read first. A VAC mismatch of a B section is likely another problem.
Possible causes:
• Wrong voltage inverter (very unlikely but easy to check).
• System Bias board wrong J61 jumper (unlikely but easy to check)
• Defective inverter.
• Ribbon Cable
• CCM
• System Bias board defective.
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 #�� should be connected from J�1-1 to:
i. J�1-2 for 20�-230 VAC
ii. J�1-3 for �00 VAC
iii. J�1-� for ��0 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 J�2 measure
relative to TP1 or ( J�2-�, 2�VDC_RET) to J�2-12 for signal /VAC_IDAb and J�2-1� for signal /VAC_IDBb. The 2
signals should read according to this table. “0” = 10-12V; “1” = 2�V.
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 section 1A is
connected or else we would have code 22�. During the power up sequence, before power is connected to the inverters, the