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Siemens 3RT5045-1BM40 — Contactors

Siemens 3RT5045-1BM40 SIRIUS Power Contactor S3, 70 mm

MPN3RT5045-1BM40

Siemens SIRIUS S3 power contactor, 3RT5045-1BM40, 70 mm width, screw-type terminals, 21.1 kW at 690 V, snap-on mounting.

Siemens 3RT5045-1BM40 datasheet (PDF)
Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
WhatsApp AnswersFast human replies for machine-down parts
Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

3RT5045-1BM40 — Identification
ParameterValue
Contactor frame sizeS3
3RT5045-1BM40 — Ratings & Performance
ParameterValue
Rated operational current, AC-12, max.10 A
Rated value @ 400 V3 A
Rated value @ 690 V21.1 kW
Rated value @ 230 V6 A
Rated value @ 24 V6 A
Rated value @ 110 V1 A
Rated value @ 220 V0.3 A
3RT5045-1BM40 — Control & Coil
ParameterValue
Control supply voltage typeDC
3RT5045-1BM40 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT5045-1BM40 — Protection & Coordination
ParameterValue
Short-circuit coordination type 1, fusefuse gL/gG: 250 A
Short-circuit coordination type 2, fusefuse gL/gG: 160 A
Aux. switch short-circuit protection, fusefuse gL/gG: 10 A
3RT5045-1BM40 — Connection & Mounting
ParameterValue
Main circuit connectionscrew-type terminals
Aux. / control circuit connectionscrew-type terminals
Conductor cross-section, solid or stranded2x (2.5 ... 16 mm²)
Conductor cross-section, finely stranded w/ ferrule2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Mounting methodscrew and snap-on mounting onto 35 mm and 75 mm standard mounting rail
Side-by-side mountingYes
3RT5045-1BM40 — Durability
ParameterValue
Durability (operating cycles, typ.)10 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT5045-1BM40 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT5045-1BM40 — Mechanical
ParameterValue
Width70 mm
Height146 mm
Depth152 mm

Product details

SIRIUS S3 power contactor — 3RT5045-1BM40

The Siemens 3RT5045-1BM40 is a SIRIUS S3 power contactor, screw-type terminals on main and auxiliary circuits, rated for motor loads up to 21.1 kW at 690 V. It snaps onto standard 35 mm or 75 mm DIN rail — no adapter plate needed.

The 690 V motor rating of 21.1 kW is the AC-3 switching capacity — that's the real-world figure for induction motor starts. The insulation voltage is rated 1 000 V, giving headroom in 690 V systems. For short-circuit protection the spec calls for a gL/gG fuse rated 160 A (type of assignment 2) — that's the coordination point for your selectivity study.

Panel integration

Screw-type terminals on both main and control circuits — accepts 2x (2.5 to 16 mm²) solid/stranded or 2x (10 to 1/0 AWG). Strip length per standard practice; torque values are on the terminal marking. The contactor accepts an auxiliary switch add-on (product extension auxiliary switch = yes), so you can add feedback contacts without changing the base unit.

Frequently asked questions

What is the depth of 3RT5045-1BM40?

The depth is 152 mm, width 70 mm, height 146 mm.

Will 3RT5045-1BM40 drop into a panel wired for 3RT5046-1BM40?

Both are SIRIUS S3 contactors with the same mounting footprint — 35/75 mm DIN rail, same screw terminal layout. The 3RT5046-1BM40 is a higher-current variant; wiring gauges sized for that model will exceed what the 3RT5045-1BM40 terminals accept (2x 16 mm² max solid). No rewiring of the DIN rail or mounting holes needed, but check the conductor size against the terminal capacity.

MPN
3RT5045-1BM40