Fault route · WSE AC/DC TIG
WSE AC/DC TIG secondary inverter fault routing
Use this workflow when a WSE AC/DC TIG welder welds in DC but fails in AC mode, outputs only one polarity, ignores balance control, trips in AC, or repeatedly damages secondary inverter devices. The route separates panel command, secondary driver, secondary inverter and output feedback evidence.
Start from mode comparison
| Mode result | Meaning | First area |
|---|---|---|
| DC mode welds normally, AC mode fails | Main inverter likely works; AC secondary path is suspect. | AC/DC panel command, secondary driver, secondary inverter board. |
| Both DC and AC fail | Not only a secondary inverter issue. | Main inverter, DC bus, output path, protection, feedback. |
| AC output only one direction | One side of secondary inverter/driver may be missing. | Gate-pair drive and secondary power devices. |
| AC balance has no effect | Balance command or waveform timing path may be missing. | Panel balance pot, control-board signal, secondary driver timing. |
| AC trips breaker or blows devices | Shoot-through, failed driver, shorted devices or wrong dead-time. | Secondary driver before replacing output devices. |
Diagnostic sequence
1. Verify DC modeConfirm main inverter can weld in DC before isolating AC secondary path.
2. Check AC commandAC/DC switch and panel command must reach control/driver path.
3. Check driver supplySecondary driver needs stable auxiliary/isolated supply.
4. Check gate pairsComplementary gate signals should exist without overlap.
5. Check power devicesInspect secondary inverter devices, snubbers and output connections.
6. Check feedbackOutput feedback/cutoff may stop AC if waveform is abnormal.
Do not replace secondary devices before driver checks
Repeated secondary inverter failure usually means the driver, dead-time, snubber or command path is still abnormal. Replacing output devices without checking drive symmetry can repeat the failure.