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Siemens 3RA2120-4BA26-0AP0 — Motor Starters

Siemens 3RA2120-4BA26-0AP0 SIRIUS Direct Starter

MPN3RA2120-4BA26-0AP0

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Siemens SIRIUS direct on-line starter, Size S0, 20 A AC-3 at 400 V, Trip Class 10, screw and snap-on 35 mm DIN rail mounting, 3RA2120-4BA26-0AP0.

$101.60Ref. price · indicative, final on quote

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Siemens 3RA2120-4BA26-0AP0 datasheet (PDF)

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

Specifications

3RA2120-4BA26-0AP0 — Identification
Parameter	Value
Product designation	Direct (on-line) starter
Main circuit poles	3
Brand	SIRIUS
Load feeder size	S0
Product design / construction	for standard rail or screw mounting
Circuit-breaker size	S0
Included contactor (type)	3RT2026-1AP00
Included circuit-breaker (type)	3RV2021-4BA10
Included link module (type)	3RA2921-1AA00

3RA2120-4BA26-0AP0 — Ratings & Performance
Parameter	Value
Rated motor power at 400 V	7 500 kW
Rated voltage at AC-3, max.	690 V
Rated motor power at 460/480 V (hp)	15 hp
Rated current at 480 V	20 A
Rated current at 600 V	20 A
Rated operating frequency	50 ... 60 Hz
Rated impulse withstand voltage (Uimp)	6 kV
Rated insulation voltage Ui (AC, pollution degree 3)	690 V

3RA2120-4BA26-0AP0 — Protection & Tripping
Parameter	Value
Trip class	CLASS 10
Short-circuit protection	Yes
Rated short-circuit current at 400 V (IEC 60947-4-1)	150 000 A
Overload release setting range (current)	13 ... 20 A
Overload release type	thermal (bimetallic)
Short-circuit trip type	magnetic
Duty / utilization type (IEC 60947-6-2)	1

3RA2120-4BA26-0AP0 — Contacts & Control
Parameter	Value
Rated value	690 V
Rated voltage range at 50 Hz	230 ... 230 V
Control supply voltage type	AC
Auxiliary switch extension	Yes
Switching contact type	electromechanical

3RA2120-4BA26-0AP0 — Communication
Parameter	Value
AS-Interface protocol support	No

3RA2120-4BA26-0AP0 — Mechanical & Connection
Parameter	Value
Mounting / fastening method	screw and snap-on mounting onto 35 mm DIN rail
Mounting position	vertical
Width	45 mm
Height	193 mm
Depth	97 mm

3RA2120-4BA26-0AP0 — Environmental
Parameter	Value
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 this SIRIUS direct starter delivers

The Siemens 3RA2120-4BA26-0AP0 is a SIRIUS direct on-line starter sized for motor loads up to 20 A in AC-3 duty at 400 V — that is the rating that governs real motor switching, not the AC-1 resistive figure. The starter ships as a complete assembly: the contactor (3RT2026-1AP00) and link module (3RA2921-1AA00) are included, so it lands on the panel ready to wire into the motor branch circuit.

The S0 feeder size means it occupies a 45 mm width on the rail — a standard single-module slot. Depth is 97 mm, height 193 mm. Main circuit connections are screw-type terminals, standard for panel building.

Operating conditions and ratings

Frequently asked questions

What is the trip class of the 3RA2120-4BA26-0AP0?

Trip Class 10, which means it allows 10 seconds of motor starting current before tripping — suitable for standard induction motors with normal inertia loads.