Protecting Electronics Before Welding
This is disconnecting the supply connection of electronic units before electric arc welding is done on the tractor. Welding current looks for a path through the chassis, and if that path passes through an electronic device the board is permanently damaged. Disconnecting the battery terminals and clamping the earth lead close to the welding area are the basic precautions.
In arc welding a current of hundreds of amps follows the lowest resistance path from the weld point to the earth clamp. If a wiring harness or an electronic unit lies on that path, part of the current passes through it. In addition, the arc produces high frequency voltage transients on the line.
- Order: first switch off the ignition, then disconnect the battery negative and then the positive terminal, then if possible disconnect the connectors of the electronic units.
- Earth clamp: it is clamped to the part being welded, as close as possible and to clean metal. A clamp attached far away sends the current around the whole vehicle.
- Afterwards: refit the connections in reverse order; on first power-up, visually confirm that the system behaves normally.
The same care applies to partial disassembly: the precaution is not skipped just because the welded area is far away. This is a field rule valid for all products containing a control board, such as the ELF-812, LFT54 and the HCT series.
The context in which this term is used: Converting a tractor hydraulic lever to electronic control