Joslyn Clark MVC series vacuum contactors are three-phase medium-voltage contactors rated 2300–7200 V and 200–1200 A, for motors up to 7000 hp at 6600 V. Their modular construction simplifies installation and inspection; terminals are arranged in-line with an alternating layout - line and load on the same side, ideal for reduced-voltage starters using a dropout contactor.
Full phase-to-phase insulation, BIL - basic impulse insulation level - 60 kV. Rated voltage 2500 / 5000 / 7200 V; rated current 200 / 400 / 600 A (up to 1200 A). Breaking capacity in E1 class (switching class according to IEC 60470): 20 MVA apparent power at 2.5 kV, 40 MVA at 5 kV, 60 MVA at 7.2 kV ≈ 4.62 kA; in coordination with a fuse (E2 class, 5 kV): 400 MVA / 45.7 kA RMS. One-second current 6000 / 7000 / 9000 A; dielectric withstand 20,000 V (1 min). Mechanical/electrical life 750,000 / 250,000–600,000 cycles; operating frequency 300 operations/h; weight 25.4 kg. Coils: 110/120 V AC, 220/240 V AC, 125 V DC, 250 V DC.
Railway applications: stationary medium-voltage distribution and motor switching in rolling-stock maintenance facilities (depots, workshops), tunnel ventilation, pumping stations and tunnel-boring machine power supplies. Industrial-design apparatus (IEC 60947) - not intended for onboard rolling-stock installation without manufacturer confirmation.
