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Siemens 3RT7045-1AH20 — Contactors

Siemens 3RT7045-1AH20 Contactor, S3, AC-3 690 V, 3-pole

MPN3RT7045-1AH20

Siemens SIRIUS 3RT7045-1AH20, size S3 contactor, 3-pole main contacts, AC-3 rated 690 V, screw-type terminals, IP20 front, snap-on 35/75 mm DIN rail.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

3RT7045-1AH20 — Identification
ParameterValue
Contactor frame sizeS3
3RT7045-1AH20 — Ratings & Performance
ParameterValue
Rated value @ 400 V3 A
Rated value @ 690 V1 A
Rated value @ 230 V6 A
3RT7045-1AH20 — Control & Coil
ParameterValue
Control supply voltage typeAC
Rated value @ 50 Hz0.27
Rated value @ 50 Hz42 V
3RT7045-1AH20 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliabilityacceptability for PLC control (17 V, 5 mA)
3RT7045-1AH20 — Protection & Coordination
ParameterValue
Short-circuit coordination type 1, fusegL/gG NH 3NA: 200 A
Aux. switch short-circuit protection, fusefuse gL/gG: 10 A
3RT7045-1AH20 — Connection & Mounting
ParameterValue
Main circuit connectionscrew-type terminals
Aux. / control circuit connectionscrew-type terminals
Conductor cross-section, solid or stranded2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 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
3RT7045-1AH20 — Environmental
ParameterValue
Operating temperature range-10 ... +55 °C
Storage temperature range-25 ... +70 °C
Installation altitude, max.2 000 m
3RT7045-1AH20 — Mechanical
ParameterValue
Width70 mm
Height148 mm
Depth139 mm

Product details

The coil is AC-operated; closing power draw is 0.62 W, holding at 0.27 W. For fault coordination, the upstream fuse requirement is a gL/gG 200 A NH 3NA type.

Environmental and terminal specs

Rated IP20 on the front (finger-safe), IP00 at the terminals — so the wiring area is not touch-protected; plan for enclosure-level guarding. Operating temperature range is -10 to +55 °C, storage from -25 to +70 °C. Pollution degree 3 (conductive pollution, typical for industrial control panels). Main and auxiliary/control circuits use screw-type terminals, accepting 2x (0.5…1.5 mm²) solid or stranded, or 2x (0.75…2.5 mm²) finely stranded with ferrules.

Frequently asked questions

What are the key dimensions?

Width 70 mm, height 148 mm, depth 139 mm. It is a size S3 contactor.

What is the AC-3 rated voltage and how does it affect motor switching?

The AC-3 rated voltage maximum is 690 V. That means it can switch three-phase induction motors on and off under full load up to that voltage, at up to 800 cycles per hour. The operating current at AC-3 varies with voltage — at 400 V it is rated 3 A for the auxiliary contacts, but the main contact rating is defined by the motor current; the 690 V ceiling is the insulation and switching limit.

Does the 3RT7045-1AH20 drop into a panel designed for the 3RT7045-1AG20?

Yes — both are size S3 contactors with the same footprint (70 mm width, same mounting rail and screw-type terminals). The difference is the coil voltage: the -1AH20 is AC-operated, while the -1AG20 uses a different coil variant. If the panel wiring and control supply match AC coil voltage, it is a direct mechanical swap.

MPN
3RT7045-1AH20