Size S0 direct-on-line starter — what it packs
The 3RA2125-4DE27-0FB4 is a Siemens SIRIUS direct-on-line starter, size S0, combining a contactor, thermal bimetallic overload relay (Class 10), and magnetic short-circuit release in one assembly. It ships with the contactor 3RT2027-2FB40, link module 3RA2921-2AA00, and circuit breaker 3RV2021-4DA25 — a matched set for motor starting and protection up to 11 kW at 400 V AC-3.
Mounting and terminal reality
Both main and auxiliary/control circuits use spring-loaded terminals — no screw torquing needed, which speeds panel wiring and reduces connection errors. Dimensions are 45 mm wide, 107 mm deep, 243 mm tall — the S0 footprint fits standard motor starter bays in distribution panels.
Duty ratings and thermal limits
Rated 11 kW at 400 V AC-3 (max 690 V AC-3), 50/60 Hz — the AC-3 rating covers squirrel-cage motor switching, where the starter makes and breaks stalled-rotor current. Operating temperature range is -20 to +60 °C, with 10 to 95 % relative humidity; surge voltage resistance is 6 kV, adequate for industrial mains with typical transient levels.
Lifecycle and sourcing — active, quoted to order
No stock-holding claim — quoted per order.