Siemens 3RT1035-1BB40 Sirius Power Contactor: Complete Technical Guide and Application Analysis
On this page
What is the Siemens 3RT1035-1BB40 contactor?
The Siemens SIRIUS 3RT1035-1BB40 power contactor — size S2, three box-terminal poles with a built-in NO + NC auxiliary contact, driven by a DC 24 V coil that connects through a white plug-on terminal block moulded A1+ / −A2 · DC 24V. The rating label on the body is the authority: Ie AC-1: 50 A, Ui 690 V · AC-3: 7.5 kW / 15 kW / 18.5 kW at 230 / 400 / 690 V (32 A / 32 A / 30 A), with SCPD data (Iq 50 / 100 / 50 kA; Type 1 32/125/80 A; Type 2 32/63/63 A), JEM AC3.1.0-0, and the UL/CSA tables to 575 V (3-phase 10/10/25/30 HP, break-all-lines 55 A 600 V, 5 kA RK5 1/50 A). One honest note on ordering: the carton print says "AC-3 5KW 400V", but the body rating label — which is the document that governs — says 18.5 kW at 400 V; we ship and price by the label. Wiring data from the side tag: mains 2×0.75–16 mm² (single 25/35 mm²), auxiliaries 0.5–2.5 mm², PZ2 screwdriver, 3–4.5 Nm on the poles and 0.8–1.2 Nm on the small terminals, 22.5 mm strip. Made in Germany, production codes G/120730 (rating label) and G/091021·E05· (face), instruction reference 3ZX1012-0RT04-1AA1, mounting M4 on a 45 × 95 pattern or 35 mm rail. Two pieces, brand new in original boxes, recorded 22 December 2025 at about 1.5 kg, one-year warranty. Fifteen photos plus the warehouse video below.
Part details
| Field | Value |
|---|---|
| Manufacturer | Siemens — SIRIUS family, Made in Germany |
| Order number | 3RT1035-1BB40 (size S2) |
| Contacts | 3 poles, box terminals (1L1/3L2/5L3 → 2T1/4T2/6T3) + built-in 1 NO + 1 NC auxiliary |
| Coil | DC 24 V — plug-on terminal block moulded A1+ / −A2 · DC 24V |
| Rating label | Ie AC-1 50 A, Ui 690 V · AC-3 7.5 / 15 / 18.5 kW at 230 / 400 / 690 V (32 / 32 / 30 A) |
| SCPD | Iq 50 / 100 / 50 kA; Type 1 32 / 125 / 80 A; Type 2 32 / 63 / 63 A; JEM AC3.1.0-0 |
| UL / CSA | LISTED 165C IND. CONT. EQ: 1PH HP 5/5 · 3PH HP 10/10/25/30 · break all lines 55 A 600 V · 5 kA 500 V max RK5 fuse/CB 1/50 A · CSA NEE.1/ASME A17.5 elevator switching, no-current 3PH 10/25/30 |
| Wiring | Mains 2×0.75–16 mm² (1× up to 25/35 mm²), AWG 18–2; aux 0.5–2.5 mm², AWG 18–14; PZ2; 3–4.5 Nm poles, 0.8–1.2 Nm aux; 22.5 mm strip |
| Mounting | 35 mm DIN rail or M4 screws on 45 × 95 mm; PA66-GF25FR body |
| Traceability | G/120730 ·E05· (rating label) · G/091021·E05· (face) · 3ZX1012-0RT04-1AA1 · barcodes 4011209 294349 / 307889 · box *01957724* · G/141208 376 |
| Box print note | Carton reads "AC-3 5KW 400V"; the body rating label (18.5 kW / 400 V) governs |
| Condition / quantity | Brand new in original boxes — 2 pieces |
| Weight | About 1.5 kg as recorded |
| Intake recorded | 22 December 2025 |
| Warranty | One year |
Why the DC coil changes the wiring, not just the voltage
The BB in 1BB40 means the coil takes 24 V DC, and SIRIUS DC coils are wired differently from the AC versions you may be used to: the coil feeds through that white plug-on module moulded A1+ / −A2, so polarity matters — swap the two wires and the coil simply will not pull in. The module pops off for panel wiring and seats with a click, and because the DC coil electronics live inside the contactor body, no external suppression unit is required in the standard arrangement. Everything else is classic S2 practice: box terminals that clamp conductors up to 35 mm² single-wire at 3–4.5 Nm, the 18.5 kW / 32 A AC-3 rating for motors in that class, and the built-in NO + NC auxiliary feeding your PLC's run feedback and interlock without an add-on block. Type 2 coordination at 32 A (per the label's SCPD table) means the upstream 3RV motor starter protects both the contactor and the motor without welding the poles on a short — which is the whole reason panels are specified around this family. Match the coil to the control supply first, the frame to the motor second, and the two units photographed here will drop straight into that scheme.
Photos
All images below are original warehouse photos of the exact contactors covered by this record, taken before dispatch. Click any photo to view it full size.
The AC-coil sibling of this size is listed in our shop as the 3RT1035-1CP04 contactor page; the 3BB40 variant is on the 3RT1035-3BB40 page.
Sourcing help
KOEED stocks Siemens SIRIUS contactors in AC and DC coil versions, new and refurbished grades. Send the order number for a quote.
Need a quote for this part?
Send us the part number or article link — we will confirm price, availability and lead time.
