Siemens 3RA6120-2CB32

Model Code Explanation

1. Core Technical Specifications

Electrical Data

Type: SIRIUS Compact Load Feeder / Direct On-Line Starter

Rated voltage: 690 V AC, 3-phase

Control voltage: 24 V AC/DC (50/60 Hz)

Rated operational current: 1–4 A

Motor power rating: 1.5 kW at 400 V, 3 kW at 690 V

Auxiliary contacts: 1 NO + 1 NC

Protection: Electronic overload protection, short-circuit protection

Degree of protection: IP20

Mechanical Data

Width: 45 mm

Mounting: Standard 35 mm DIN rail mounting (screw and clip fixing)

Weight: Approx. 1.51 kg (3.335 lb)

Connection type: Main circuit-spring-loaded terminals; Auxiliary circuit-spring-loaded terminals

III. Operating Environment

Typical Applications

Control of small fans and pumps

Light-duty equipment such as conveyors and mixers

HVAC control in building automation systems

Auxiliary equipment control in industrial automation production lines

Replacement of conventional contactor + thermal relay combinations to save cabinet space

1. Replacement Models and Brand Comparison

Siemens Replacement in Same Series

Replacement Models from Other Brands

1. Official Ordering Information

Official order number: 3RA6120-2CB32 (globally unified)

Product status: Active product (PLM: PM300)

Minimum packaging: 1 unit/package

Certifications: CE, UL, CSA and other international certifications

1. Complete Model List for 3RA61 Series (1–4 A Range)

VII. Engineering Recommendations and Risk Warnings

Installation Notes

1. Mounting orientation: Vertical installation preferred; 10% derating required for horizontal installation
2. Heat dissipation space: Reserve at least 5 mm on both sides for adequate cooling
3. Wiring specifications: Main circuit conductor cross-section 0.5–2.5 mm²; auxiliary circuit 0.5–1.5 mm²
4. Control circuit: Surge suppressor recommended to protect against voltage spikes

Risks in Cross-Brand Replacement

1. Ensure overload protection curve matches the motor to avoid protection failure
2. Spring-loaded and screw terminals are not directly interchangeable; rewiring and retightening required
3. Electronic overload parameters must be reset according to motor nameplate data
4. Short-circuit protection characteristics may vary between brands; short-circuit withstand rating must be verified

Maintenance Points

1. Regularly check terminal tightness, especially in vibrating environments
2. Clean dust from the device surface to maintain heat dissipation
3. Periodically test overload protection function
4. Consider voltage stabilizer if control voltage fluctuates beyond ±10%

VIII. Summary

The Siemens 3RA6120-2CB32 is a compact, integrated direct on-line starter combining contactor, short-circuit protection and electronic overload protection. It is designed for small three-phase motors (1.5 kW at 400 V, 3 kW at 690 V). Featuring spring-loaded terminals for quick wiring and a narrow 45 mm width to save cabinet space, its 24 V AC/DC wide-range control voltage supports various automation systems.

Typical Applications of Siemens 3RA6120-2CB32

This is a Siemens SIRIUS compact direct on-line starter with a rated current of 1–4 A, suitable for low-power three-phase motors, especially in applications requiring small motors, light loads and compact installation space.

1. Fan Applications

Small axial fans, cabinet cooling fans

Fans for air conditioning units, fresh air system fans

Small smoke exhaust fans, cooling fans

2. Pump Applications

Small booster pumps, circulation water pumps

Cooling water pumps, lubrication pumps

Make-up pumps for hydraulic systems

3. Conveying and Light Industry Machinery

Small belt conveyors, roller conveyors

Feeders, small elevators

Packaging machines, labeling machines, small conveyors

4. Machine Tools and Automation Auxiliaries

Machine tool cooling pumps, lubrication pumps

Small chip conveyors

Drive motors for tooling and fixtures

5. Food, Packaging and Textile Light Industry

Small mixers and blenders

Textile small rollers, feeding mechanisms

Small drive motors for food processing

6. Building and HVAC Systems

Drive for small valve actuators

Air handling unit fans, coil fans

Small water treatment supporting equipment

7. General Industrial Auxiliaries

Small fans, vibration motors

Auxiliaries for small air compressors

Auxiliary drive motors for various equipment

Suitable for all applications involving three-phase small motors up to approximately 1.5 kW at 400 V with current 1–4 A, requiring direct starting, overload + short-circuit protection, and compact size with fast wiring.