SIRIUS S2 Power Contactor — 3RT1034-1BD44
The Siemens 3RT1034-1BD44 is a SIRIUS-branded power contactor in the S2 frame size, designed for switching motor loads in industrial control panels. It is rated for 18.5 kW at 500 V and 10 kW at 690 V under AC-3 duty, which covers the majority of three-phase induction motor applications up to that power. Mounts via screw and snap-on onto a 35 mm DIN rail per DIN EN 50022, and accepts screw-type terminals for the main current circuit — a standard choice for panel builders who prefer terminated ring lugs or direct cable entry. The front face carries IP20 protection; the terminal area is IP00, so the contactor is intended for installation inside an enclosure that provides the final ingress protection.
Key Ratings and What They Mean for Fit
The AC-3 motor-switching rating of 18.5 kW at 500 V and 10 kW at 690 V defines the maximum three-phase motor load this contactor can switch under typical starting conditions (6–8× locked-rotor current). For a 400 V supply, the corresponding AC-3 current is 29 A — the value that governs thermal sizing in a motor starter. Mechanical endurance is rated at 10 million operations typical, meaning the contactor's mechanical life far exceeds its electrical life under heavy switching — a useful margin for high-cycle applications like conveyor indexing or pump cycling. Operating temperature spans -25 °C to +60 °C, with storage from -55 °C to +80 °C. The -25 °C lower limit is common for indoor panel installations; if the panel sits in an unconditioned outdoor shelter in a cold climate, verify the ambient stays above that threshold. The auxiliary contact ratings cover 24 VDC at 10 A down to 220 VDC at 0.3 A — these are resistive-load figures; for inductive DC loads like relay coils, derate or add a free-wheeling diode across the load.
Sourcing and Lifecycle
RoHS compliance is confirmed per the substance prohibitance date of May 1, 2012, covering the EU RoHS directive. No separate UL or CSA listing is shown in the spec record, but the SIRIUS series broadly carries these approvals — confirm the specific certification mark on the nameplate if the installation requires a UL-listed device.
Integration Notes
The S2 frame measures 112 mm high, 55 mm wide, and 179 mm deep — a compact footprint that fits alongside other SIRIUS components on the same DIN rail without additional spacing when side-by-side mounting is permitted. Terminal capacity accepts solid conductors from 0.5 mm² up to 4 mm² (two conductors per clamp), and stranded conductors up to 25 mm². The minimum permissible cross-section at 40 °C ambient is 16 mm² for the main circuit, which guides feeder sizing. Switching frequency varies by duty: up to 1,200 operations per hour at AC-1 (resistive), 1,000 at AC-3 (motor), and 250 at AC-4 (plugging/inching). For high-cycle applications like reversing starters, the AC-4 limit is the binding constraint.