Siemens 3RA2120-4DE27-0AP0 SIRIUS Motor Starter, 25A AC-3

Name: 3RA2120-4DE27-0AP0
Brand: Siemens
SKU: 3RA2120-4DE27-0AP0
Availability: LimitedAvailability
Author: Strategic Sourcing Sven

Specifications

Identification

3RA2120-4DE27-0AP0 — 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)	3RT2027-2AP00
Included circuit-breaker (type)	3RV2021-4DA20
Included link module (type)	3RA2921-2AA00

Ratings & Performance

3RA2120-4DE27-0AP0 — Ratings & Performance
Parameter	Value
Rated motor power at 400 V	11 000 kW
Rated voltage at AC-3, max.	690 V
Rated motor power at 460/480 V (hp)	20 hp
Rated current at 480 V	25 A
Rated current at 600 V	25 A
Rated operating frequency	50 ... 60 Hz
Rated impulse withstand voltage (Uimp)	6 kV
Rated insulation voltage Ui (AC, pollution degree 3)	690 V

Protection & Tripping

3RA2120-4DE27-0AP0 — 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)	18 ... 25 A
Overload release type	thermal (bimetallic)
Short-circuit trip type	magnetic
Duty / utilization type (IEC 60947-6-2)	2

Contacts & Control

3RA2120-4DE27-0AP0 — 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

Communication

3RA2120-4DE27-0AP0 — Communication
Parameter	Value
AS-Interface protocol support	No

Mechanical & Connection

3RA2120-4DE27-0AP0 — Mechanical & Connection
Parameter	Value
Mounting / fastening method	screw and snap-on mounting onto 35 mm DIN rail
Mounting position	vertical
Width	45 mm
Height	243 mm
Depth	107 mm

Environmental

3RA2120-4DE27-0AP0 — 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

Panel fit and mounting constraints

The 3RA2120-4DE27-0AP0 occupies a 45 mm wide footprint on 35 mm DIN rail, with a height of 243 mm and depth of 107 mm — the S0 frame size dictates the panel cut-out and busbar spacing. Mounting is vertical only, secured by screw and snap-on onto the DIN rail. Clearance requirements: 50 mm above, 20 mm forward, 10 mm below, 20 mm at the sides, and 0 mm backward — plan the enclosure layout around these ventilation and wiring access zones.

Motor starting duty and trip coordination

The supplied contactor is a 3RT2027-2AP00, and the link module is 3RA2921-2AA00 — these are pre-assembled and tested as a matched set.

Sourcing and lifecycle position

For BOM planning, the S0 frame size and 45 mm width are consistent across the SIRIUS 3RA2 series, so a panel layout using this starter can be replicated with other S0-rated units without re-spacing the DIN rail.

Frequently asked questions

What is the AC-3 rating at 400 V for this motor starter?

The 3RA2120-4DE27-0AP0 is rated 25 A at AC-3 duty at 400 V, which corresponds to 11 kW motor capacity at 400 V. This is the key rating for sizing motor loads.

What clearance is needed around this starter in the panel?

Minimum clearances: 50 mm above, 20 mm forward, 10 mm below, 20 mm at the sides, and 0 mm backward. These ensure adequate ventilation for the Class 10 trip curve and access to the spring-loaded terminals.