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Siemens 3RT1045-1BG44 — Contactors

Siemens 3RT1045-1BG44 SIRIUS Power Contactor, Size S3, 125 V

MPN3RT1045-1BG44

Siemens SIRIUS power contactor, size S3, 125 VDC coil, screw-type terminals, 45 kW at 500 V AC-3, 70 x 146 x 201 mm.

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

3RT1045-1BG44 — Identification
ParameterValue
Contactor frame sizeS3
3RT1045-1BG44 — 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
3RT1045-1BG44 — Control & Coil
ParameterValue
Control supply voltage typeDC
3RT1045-1BG44 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT1045-1BG44 — 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
3RT1045-1BG44 — Connection & Mounting
ParameterValue
Main circuit connectionscrew-type terminals
Aux. / control circuit connectionscrew-type terminals
Conductor cross-section, solid2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), max. 2x (0.75 ... 4 mm²)
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
3RT1045-1BG44 — Durability
ParameterValue
Durability (operating cycles, typ.)10 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT1045-1BG44 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT1045-1BG44 — Mechanical
ParameterValue
Width70 mm
Height146 mm
Depth201 mm

Product details

AC-3 Motor Switching Duty

The 3RT1045-1BG44: The headline rating for motor loads is 45 kW at 500 V AC-3, with a mechanical life of 10 million operations typical. The AC-3 maximum switching rate is 1 000 operations per hour, which covers most conveyor, pump, and fan cycling without derating. For resistive loads (AC-1), the maximum rate is 900 ops/h; for high-inrush AC-4 duty (plugging, inching), it drops to 300 ops/h.

Coil and Auxiliary Ratings

The 125 VDC coil has an arcing time of 10 to 15 ms and a DC dropout time of 14 to 20 ms. Auxiliary contact ratings at various DC voltages: 10 A at 24 V, 2 A at 60 V, 1 A at 110 V, 0.3 A at 220 V, 6 A at 230 V, and 3 A at 400 V. For AC-4 at 400 V, the contactor is rated 66 A. The coil power dissipation at 1000 V is 37 W.

Dimensions: 70 mm wide, 146 mm high, 201 mm deep. The depth of 201 mm is the full body dimension — verify clearance against enclosure depth, especially with duct covers or door-mounted devices. The screw-type terminals on the main circuit accept 2x (10 to 50 mm²) stranded; auxiliary terminals accept 2x (0.5 to 1.5 mm²) solid, 2x (0.75 to 2.5 mm²) solid, or max 2x (0.75 to 4 mm²) solid. The solid/stranded range for the main terminals is 2x (2.5 to 16 mm²).

Frequently asked questions

What are the key dimensions of 3RT1045-1BG44?

Width 70 mm, height 146 mm, depth 201 mm. The depth of 201 mm is the full body dimension — ensure adequate enclosure clearance.

What compliance documentation does Siemens provide for 3RT1045-1BG44?

RoHS compliance date is 05/01/2012. The contactor carries pollution degree 3 rating. IP20 on the front with cover; IP00 at the terminals. Operating temperature -25 to +60 °C, storage -55 to +80 °C.

MPN
3RT1045-1BG44