Diagnostic workflow
Submerged Arc Power Source Interface Fault Routing
A symptom-first WelderData workflow for SAW systems where the wire-feed tractor, control box and welding power source must be diagnosed as separate sections.
Database summary
Many submerged arc faults are misdiagnosed because the tractor and the welding power source are treated as one unit. A no-weld condition may come from a start command that never reaches the source, a source contactor that does not enable, a feedback line that holds the source back, or a real power-output fault.
This workflow routes the fault by evidence: does the tractor respond, does the wire feed or retract, does the source receive enable, does the output voltage or current appear, and does the feedback path match the process command.
Fault routing table
| Symptom | First section to check | Do not jump directly to |
|---|---|---|
| Tractor runs but no welding output | Source enable, contactor, command interface | Replacing wire-feed control parts |
| Wire feed works manually but not during welding | Start sequence, controller mode, interlock and arc-start logic | Main rectifier replacement |
| Output voltage exists but wire feed does not stabilize | Arc-voltage feedback, controller compensation and wire-feed command | Assuming power source is healthy without feedback check |
| Current output appears but display/control is wrong | Feedback scaling, panel command, external measurement | Replacing SCR or IGBT devices first |
| Stop command does not release source correctly | Stop relay, arc-voltage shutdown path and source contactor | Only checking the tractor motor |
Minimum measurement set
- Controller supply and start command at the source interface.
- Source contactor or output-enable signal.
- Open-circuit voltage and welding-output evidence.
- Arc-voltage feedback return to the controller.
- Current-feedback or shunt signal if current regulation is involved.
- Wire-feed response during manual jog, start and active arc conditions.
ZD5 / MZC fault-flow additions
For ZD5 / MZC systems, first separate the power-source state from the tractor/controller state. A fan-running/no-weld condition should be routed through contactor enable, output voltage, SCR condition and cable evidence before replacing a controller board.
| Observed condition | Route through | Useful evidence |
|---|---|---|
| Power indicator off | Input supply, fuse, indicator/control supply | Three-phase input and 24V-class indicator/control path. |
| Indicator on and fan running, no weld | Contactor, output voltage, SCR1–SCR6, controller enable | Whether contactor closes and whether secondary/output voltage appears. |
| Output stops during welding | Thermal protection, output cable and source shutdown evidence | Overheat indicator, cable continuity and repeatability. |
| Wire sticks or current is unstable | Process settings, feed mode, R300 reference and burn-back behavior | Wire sticking mode, R300 around 160Ω and voltage setting direction. |