Active production — current SIRIUS line
The 3RA2120-4CA27-0AP0 is a current-production SIRIUS direct on-line starter, Size S0, from Siemens. It ships as a pre-assembled kit with the supplied contactor 3RT2027-1AP00 and link module 3RA2921-1AA00 — not loose components that need field assembly. The Class 10 trip characteristic means it protects standard squirrel-cage motors during start-up without nuisance tripping on normal acceleration.
AC-3 motor switching and overload protection
The 690 V maximum across both rated value and AC-3 ceiling means it handles 400 V and 480 V systems with headroom. The operating temperature range of -20 to +60 °C with temperature compensation keeps the trip curve stable across the panel ambient.
DIN rail mounting and panel footprint
Dimensions are 45 mm wide, 193 mm high, and 97 mm deep, with required clearances of 50 mm upward, 20 mm forward, 10 mm downward, and 20 mm at the side for airflow and wiring access. Main circuit connections use screw-type terminals — no special tooling needed for field wiring. The Size S0 circuit-breaker and load feeder share the same mounting footprint, simplifying multi-starter panel layouts.
Motor sizing across line voltages
This covers North American and IEC motor frames without needing a different starter variant.