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Siemens 3RT1045-3BM40 — Contactors

Siemens 3RT1045-3BM40 SIRIUS Power Contactor, S3, 66A AC-4,

MPN3RT1045-3BM40

Siemens SIRIUS, power contactor, S3 size, 3RT1045-3BM40, screw-type terminals, AC-4 rated 66 A at 400 V, motor rating 45 kW at 500 V, IP20 front, snap-on 35/75 mm rail.

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

3RT1045-3BM40 — Identification
ParameterValue
Contactor frame sizeS3
3RT1045-3BM40 — Ratings & Performance
ParameterValue
Rated operational current, AC-12, max.10 A
Rated operational current, AC-4 @ 400 V66 A
Rated value @ 400 V3 A
Rated value @ 500 V45 kW
Rated value @ 690 V21.1 kW
Rated value @ 230 V6 A
Rated value @ 24 V10 A
Rated value @ 60 V2 A
Rated value @ 110 V1 A
Rated value @ 220 V0.3 A
3RT1045-3BM40 — Control & Coil
ParameterValue
Control supply voltage typeDC
3RT1045-3BM40 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT1045-3BM40 — 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
3RT1045-3BM40 — Connection & Mounting
ParameterValue
Main circuit connectionscrew-type terminals
Aux. / control circuit connectionspring-loaded terminals
Conductor cross-section, solid2x (0.25 ... 2.5 mm²)
Conductor cross-section, solid or stranded2x (2.5 ... 16 mm²)
Conductor cross-section, finely stranded w/ ferrule2x (0.25 ... 1.5 mm²)
Mounting methodscrew and snap-on mounting onto 35 mm and 75 mm standard mounting rail
Side-by-side mountingYes
3RT1045-3BM40 — Durability
ParameterValue
Durability (operating cycles, typ.)10 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT1045-3BM40 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT1045-3BM40 — Mechanical
ParameterValue
Width70 mm
Height146 mm
Depth152 mm

Product details

Its headline motor rating is 45 kW at 500 V (AC-3 duty,), which means it directly switches a three-phase induction motor of that size in a standard pump, fan, or conveyor application — no external bypass contactor needed. The AC-4 rating of 66 A at 400 V governs plugging and inching duty: if the load requires frequent reversal or jogging, this is the current limit that determines thermal stress on the contacts, not the AC-3 figure. Screw-type terminals on the main circuit accept stranded conductors up to 2x 50 mm² and solid up to 2x 2.5 mm², covering the full range from control wiring to motor feeders. The IP20 front face with cover/box terminal means the panel builder can leave the front exposed for troubleshooting — the IP00 terminal body is protected once enclosed in the panel, which is standard for DIN-rail mounted gear.

Mounting and integration — DIN rail and side-by-side

Snaps onto standard 35 mm or 75 mm mounting rail, and side-by-side mounting is permitted — no mandatory spacing between units, which keeps the panel row dense. The S3 frame measures 70 mm wide by 146 mm tall by 152 mm deep, so a row of three fits in under 210 mm of DIN-rail width.

Maximum mechanical switching frequency is 10,000,000 operations typical. The electrical switching frequency depends on duty: 1,000 operations per hour in AC-3, 900 in AC-1 resistive, 400 in AC-2, and 300 in AC-4. For a conveyor running at 30 cycles per hour, the AC-3 rating leaves headroom; for a press with frequent jogging at 150 cycles per hour, the AC-4 limit of 300 ops/h still fits but the contact wear will be higher — plan spares accordingly. DC switching ratings are given for the auxiliary circuit: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V — these govern the control-side contacts, not the main poles.

No phase-out or last-time-buy notice is attached to this order code. The substance prohibition date of 05/01/2012 aligns with the original RoHS compliance cutoff; expect the current production to meet RoHS and REACH requirements. Compliance documentation (CE, UL, CSA) is standard for the SIRIUS line — confirm the specific UL file number with the order if a panel UL 508A listing requires it.

Frequently asked questions

What is the closest functional second-source to 3RT1045-3BM40?

The closest peer within the SIRIUS family is the 3RT5046-1BM40, which shares the S3 frame size and screw-terminal format. The 3RT1045-3BM40 carries a higher AC-4 current rating (66 A vs the 3RT5046-1BM40's lower AC-4 figure), so if your application requires frequent plugging or inching duty, the 3RT1045-3BM40 is the better fit. The 3RT1044-1FB46 is a smaller S2-frame unit and will not drop into a panel wired for the S3 footprint without re-drilling the mounting holes and re-terminating the motor leads.

Where can I buy 3RT1045-3BM40 and how is it quoted?

This part is sourced and quoted to order against an RFQ through independent industrial-automation distribution channels. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm price and lead-time estimate.

What is 3RT1045-3BM40's depth for panel planning?

The depth is 152 mm. Combined with the 70 mm width and 146 mm height, the S3 frame requires a minimum enclosure depth of roughly 170 mm to allow clearance for the screw terminals and outgoing cables.

What wire sizes does 3RT1045-3BM40 accept?

The screw-type main terminals accept stranded conductors from 2x 10 mm² up to 2x 50 mm² and solid conductors from 2x 0.25 mm² up to 2x 2.5 mm². The auxiliary terminals accept 2x 2.5 to 16 mm² stranded or solid.

MPN
3RT1045-3BM40