Galvanised Enclosure
Protecting a sheet-metal enclosure against corrosion by coating it with zinc. Because zinc is a more active metal than steel, it sacrifices itself even at a scratch or a cut edge and protects the sheet steel underneath from rusting. The AXI LFT20 and LFT54 boxes are galvanised metal; the LFT54 box measures 155 × 175 × 70 mm.
The working principle of galvanised coating is cathodic protection: when zinc and steel are in contact in a damp environment, the zinc oxidises first and the steel is protected. That is why, unlike painted sheet metal, a small scratch does not immediately turn into a spot of rust.
- Impact: a sheet-metal enclosure is more resistant to flying stones and branch impacts than a plastic box; in field conditions this makes a meaningful difference.
- Heat: a metal enclosure transfers the heat inside to the outside, which is an advantage for the electronics.
- Limit: galvanised coating is not infinite; continuous contact with fertiliser, salt or chemicals consumes the coating. At points where contact is permanent, the unit needs to be relocated.
Enclosure material and waterproofing are separate matters. The LFT20's IP66 rating means complete dust-tightness and resistance to powerful water jets from any direction; continuous immersion is outside the scope of this rating. The enclosure being galvanised is a choice made against corrosion and impact, not against water.
Context in which this term is used: Converting a tractor hydraulic lever to electronic control