It switches motor loads in AC-3 utilisation category, rated for 12 A in that duty — meaning it handles the inrush and break current of a squirrel-cage motor during start-up and run transitions. The contact configuration is 3 x 3P (3 NO), giving three normally-open power poles per phase for the main, star, and delta contactors. The coil is wound for 415 V AC, common on 400 V three-phase networks across Europe and Asia.
For a new design, a current-production TeSys D star delta starter with the same 12 A AC-3 rating and 415 V AC coil should be selected by reviewing the latest catalogue; the obsolete LC3D12AN7 is a replacement-only part for existing panels.
Mechanical robustness is specified for vibration: 2 Gn contactor open, 4 Gn closed over 5–300 Hz. Shock withstand is 10 Gn open, 15 Gn closed for 11 ms. These figures matter if the starter is mounted on a machine frame subject to impact or continuous vibration — a conveyor drive, compressor skid, or press line. Altitude rating is 3000 m without derating. Above that, air density affects dielectric withstand and thermal dissipation — the starter must be derated per the manufacturer's guidelines.