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Siemens 3RA2120-1KA24-0BB4 — Motor Starters

Siemens SIRIUS 3RA2120-1KA24-0BB4 Direct On-Line Starter, 12

MPN3RA2120-1KA24-0BB4
Active

Siemens SIRIUS, direct on-line starter, 3RA2120-1KA24-0BB4, 12 A AC-3 at 400 V, Trip Class 10, 24 VDC coil, screw terminals, size S0, 45 mm wide.

$121.92Ref. price · indicative, final on quote
Siemens 3RA2120-1KA24-0BB4 datasheet (PDF)
Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

3RA2120-1KA24-0BB4 — Identification
ParameterValue
Product designationDirect (on-line) starter
Main circuit poles3
BrandSIRIUS
Load feeder sizeS0
Product design / constructionfor standard rail or screw mounting
Circuit-breaker sizeS00
Included contactor (type)3RT2024-1BB40
Included circuit-breaker (type)3RV2011-1KA10
Included link module (type)3RA2921-1BA00
3RA2120-1KA24-0BB4 — Ratings & Performance
ParameterValue
Rated motor power at 400 V5 500 kW
Rated voltage at AC-3, max.690 V
Rated motor power at 460/480 V (hp)7.5 hp
Rated motor power at 575/600 V (hp)10 hp
Rated current at 480 V11 A
Rated current at 600 V10 A
Rated operating frequency50 ... 60 Hz
Rated impulse withstand voltage (Uimp)6 kV
Rated insulation voltage Ui (AC, pollution degree 3)690 V
3RA2120-1KA24-0BB4 — Protection & Tripping
ParameterValue
Trip classCLASS 10
Short-circuit protectionYes
Rated short-circuit current at 400 V (IEC 60947-4-1)150 000 A
Overload release setting range (current)9 ... 12.5 A
Overload release typethermal (bimetallic)
Short-circuit trip typemagnetic
Duty / utilization type (IEC 60947-6-2)2
3RA2120-1KA24-0BB4 — Contacts & Control
ParameterValue
Rated value24 ... 24 V
Control supply voltage typeDC
Auxiliary switch extensionYes
Switching contact typeelectromechanical
3RA2120-1KA24-0BB4 — Communication
ParameterValue
AS-Interface protocol supportNo
3RA2120-1KA24-0BB4 — Mechanical & Connection
ParameterValue
Mounting / fastening methodscrew and snap-on mounting onto 35 mm DIN rail
Mounting positionvertical
Width45 mm
Height193 mm
Depth107 mm
3RA2120-1KA24-0BB4 — Environmental
ParameterValue
Operating temperature range-20 ... +60 °C
Storage temperature range-50 ... +80 °C
Transport temperature range-50 ... +80 °C
Shock resistance (IEC 60068-2-27)6g / 11 ms

Product details

What It Is & Key Ratings

The 3RA2120-1KA24-0BB4: This is a Siemens SIRIUS direct on-line starter, size S0, combining a contactor and overload relay in one assembly. The unit ships with a supplied contactor (3RT2024-1BB40) and link module (3RA2921-1BA00) pre-assembled, so it arrives as a single, tested feeder ready for DIN-rail installation.

Integration & Panel Fit

The S0 footprint is 45 mm wide, 107 mm deep, and 193 mm tall, with a required clearance of 50 mm upward, 20 mm forward, and 10 mm downward for heat dissipation and wiring access. No backward clearance is needed.

Frequently asked questions

What are the key electrical ratings for this starter?

The main motor rating is 12 A at AC-3 at 400 V, with a Trip Class 10 overload curve. The coil is 24 VDC. It also carries horsepower ratings: 3 hp at 220/230 V, 7.5 hp at 460/480 V, and 10 hp at 575/600 V.

What physical size and mounting does it require?

The starter is size S0, 45 mm wide × 107 mm deep × 193 mm tall. It mounts vertically on 35 mm DIN rail with screw and snap-on fastening. Clearance needed: 50 mm above, 20 mm in front, 10 mm below; no space behind.

Does it include the contactor and link module?

Yes. The supplied contactor is 3RT2024-1BB40 and the supplied link module is 3RA2921-1BA00, pre-assembled as a single direct-on-line starter unit.

MPN
3RA2120-1KA24-0BB4