What the 3RA2120-1EA23-0BB4 carries — and what that means for a panel build
This is a Siemens SIRIUS 3RA2 non-fused direct starter, Size S0, rated for AC-3 motor switching up to 690 V. The 24 V control coil matches standard PLC-level signals — no separate 110 V or 230 V control transformer needed for the starter itself. At 480 V it is rated 3.95 A (2 hp), and at 600 V it carries 4 A (3 hp) — the current ceiling is consistent across the 480–600 V band, so the same starter covers both 480 V and 600 V motor FLA in that range.
Mounting and panel fit — DIN rail or screw, with clearances
Snaps onto standard DIN rail (35 mm) or can be screw-mounted with the included push-in lug — the same part serves both a quick-panel build and a retrofit where the rail is already full. The footprint is 45 mm wide × 193.1 mm tall × 107 mm deep — the width is a single 45 mm slot on the rail, and the depth fits a 120 mm deep enclosure with room for wiring behind the starter. Clearance requirements: 30 mm above, 10 mm below, 10 mm forward, 9 mm to the side — the tight side gap (9 mm) means adjacent starters can be packed closely on the rail, but the 30 mm top clearance must be respected for the bimetallic trip mechanism to vent heat.
What is inside the box — contactor and link module pre-assembled
The starter ships with the contactor 3RT2023-1BB40 and the link module 3RA2921-1BA00 already assembled — no separate ordering or wiring between the contactor and overload. The link module carries the power bus between the two devices and the control wiring interface. The design is a direct starter (non-reversing) — one contactor, one overload, no reversing interlock. For reversing duty you need a separate 3RA2 reversing starter or add a second contactor with mechanical interlock.
The 3RA2 series is the current SIRIUS motor starter platform; no successor order code exists for this specific variant. The 3RT2023 contactor and 3RA2921 link module inside are also current catalog items, so spares are available independently.