Siemens Soft Starter 3RW4038-1BB14

Main Product Series – Function & Application Comparison

Typical Applications & Industries:
✓ Pumps and compressors ✓ Conveyor systems and material handling
✓ Fans and ventilation systems ✓ Roller conveyors and assembly lines
✓ Milling machines and machine tools ✓ Hydraulic pumps and stirrers
✓ Mining and heavy industry ✓ ATEX hazardous area applications

Detailed Description – Siemens SIRIUS 3RW40 Soft Starter Portfolio

1. Series Overview – Compact, Efficient Motor Starting

The Siemens SIRIUS 3RW40 soft starters are designed for the soft starting and stopping of three-phase asynchronous motors in standard applications. Compared to conventional star-delta or DOL starters, 3RW40 soft starters often require only one-third of the cabinet space and reduce wiring from six to three cables. The integrated bypass contacts ensure minimum power loss during continuous operation, eliminating the need for external bypass circuits.

Key Family Features:

• ✓ Compact design – Space savings up to 66% compared to star-delta starters

• ✓ Low power loss – Integrated bypass contacts minimise heat dissipation

• ✓ Two-phase control (Polarity Balancing) – Unique patented method eliminates DC components for smooth starting

• ✓ Integrated motor overload protection – Adjustable trip classes (CLASS 10, 15, 20) – no additional overload relay required

• ✓ Adjustable current limiting – Protects motor and supply network during startup

• ✓ Integrated remote reset – Quick fault clearing from remote location

• ✓ ATEX certified – Suitable for starting explosion-proof motors with “increased safety” (EEx e) protection

• ✓ Worldwide approvals – IEC, UL/CSA, and ATEX/IEC Ex

• ✓ SIRIUS modular system – Link modules available for direct attachment to circuit breakers

2. Application Benefits

The SIRIUS 3RW40 soft starters provide measurable advantages over traditional starting methods:

3. Key Specifications by Series

3RW402 (Size S0):

• Dimensions: 45mm width

• Power loss in operation: approx. 2–8W

• Operating temp: -25°C to +60°C (with derating above 40°C)

3RW403 (Size S2):

• Dimensions: 55mm width

• Optional thermistor motor protection for full motor protection

• Up to 22kW @ 400V

3RW404 (Size S3):

• Dimensions: 70mm width

• Up to 55kW @ 400V

• Low power loss design for high-efficiency operation

3RW405 / 3RW407 (Size S6/S12):

• IP00 chassis mount for higher power ratings

• Available up to 160kW @ 400V, 280A continuous current

• Parallel connection capability for even higher power

4. Adjustable Startup Parameters

The 3RW40 soft starters offer intuitive parameter adjustment via potentiometers:

Selection Guide – Understanding the Naming Convention (Siemens 3RW40 Series)

Part Number Format: 3RW40 [Size] [Current] - [Voltage] [Terminals] [Control] [Options]

Example: 3RW4026-1BB04

Model Decoder Examples: