Why was a galvanised metal enclosure chosen, and does it rust?
The AXI LFT20 has a galvanised metal enclosure and the LFT54 a galvanised sheet-metal enclosure. The zinc in the galvanised coating both forms a physical barrier and, in scratched areas, provides cathodic protection that delays the rusting of the steel. A metal enclosure also responds better than plastic to mechanical impact and to dissipating the motor's heat.
Galvanised coating protects in two ways:
- Barrier effect: the zinc layer separates the steel from moisture and oxygen.
- Cathodic protection: zinc is a more active metal than steel. Even if the coating is scratched and the steel underneath is exposed, the surrounding zinc corrodes first and protects the steel. Painted sheet metal does not have this effect; rust starts immediately where the paint is scratched.
Its importance for an agricultural environment is considerable: fertiliser residue, chemicals, mud and constant moisture eat painted surfaces quickly. A metal enclosure is also more resistant than plastic to knocks and branch impacts, and helps carry the motor's heat away.
It is not rust-proof forever. To extend its life: cover deep scratches with zinc-based paint, do not mount the unit at a point where water constantly collects, route cable entries with a downward drip loop, and clean the enclosure at the end of the season.
The LFT20 enclosure measures 170 × 130 × 55 mm and weighs 400 g; the LFT54 is 155 × 175 × 70 mm and about 650 g.
Full coverage of the topic: Converting a tractor hydraulic lever to electronic control