Skip to main content
Log in
Siemens 3RT1045-3AC20 — Contactors

Siemens 3RT1045-3AC20 SIRIUS Power Contactor, 45 kW at 500 V

MPN3RT1045-3AC20

Siemens SIRIUS power contactor, size S3, 3RT1045-3AC20, 45 kW at 500 V AC-3, 24 V 50/60 Hz coil, screw-type terminals, snap-on DIN 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

3RT1045-3AC20 — Identification
ParameterValue
Contactor frame sizeS3
3RT1045-3AC20 — 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
3RT1045-3AC20 — Control & Coil
ParameterValue
Control supply voltage typeAC
Rated value @ 50 Hz0.8 ... 1.1
Rated value @ 50 Hz24 V
3RT1045-3AC20 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT1045-3AC20 — 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
3RT1045-3AC20 — 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
3RT1045-3AC20 — Durability
ParameterValue
Durability (operating cycles, typ.)10 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT1045-3AC20 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT1045-3AC20 — Mechanical
ParameterValue
Width70 mm
Height146 mm
Depth139 mm
3RT1045-3AC20 — Specifications
ParameterValue
At AC10 ... 25 ms

Product details

The Siemens 3RT1045-3AC20 is a SIRIUS power contactor in size S3, rated for switching motor loads up to 45 kW at 500 V in AC-3 duty, or 21.1 kW at 690 V. The 24 V 50/60 Hz coil draws the listed holding power. Screw-type terminals on the main circuit accept 2x (10... 50 mm²) stranded or 2x (0.25... 2.5 mm²) solid control wiring.

The front carries IP20 protection with the cover or box terminal fitted; the terminal body itself is IP00, meaning the wiring compartment is open to the panel environment — plan for enclosure-level sealing. Dimensions are 146 mm high, 70 mm wide, 139 mm deep — a compact S3 footprint that fits standard panel layouts without surprises.

Duty ratings and mechanical life

Rated for 1 000 switching operations per hour in AC-3 duty, 900 in AC-1, 400 in AC-2, and 300 in AC-4. Arcing time runs 10... 15 ms; the total break time at AC is 10... 25 ms.

Frequently asked questions

What is 3RT1045-3AC20 used for?

It is a power contactor for switching three-phase motor loads up to 45 kW at 500 V AC-3, or resistive loads up to the AC-1 rating. Common in conveyor, pump, fan, and compressor control panels.

Where can I buy 3RT1045-3AC20?

This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time.

Will 3RT1045-3AC20 drop into a panel specified around 3RT1044-1FB46 without rewiring?

Both are SIRIUS size S3 contactors with the same mounting rail and terminal arrangement, so the physical swap is straightforward. However, the 3RT1045-3AC20 uses a 24 V 50/60 Hz coil, while the 3RT1044-1FB46 may differ — verify coil voltage and control circuit compatibility before swapping.

What compliance documentation does Siemens provide for 3RT1045-3AC20?

As a SIRIUS product, it carries CE marking for the European market and is designed to meet IEC/EN 60947-4-1. UL and CSA listings are typical for this series; confirm specific certification marks on the nameplate or request the declaration of conformity with your RFQ.

MPN
3RT1045-3AC20