Overview
The Siemens 3RB2046-1UB0 is a solid-state electronic overload relay from the SIRIUS 3RB family, designed for inverse-time delayed protection of three-phase motors. This Class 10 relay provides fast response to overload conditions and meets IEC 60947-4-1 standards for industrial motor control applications. The relay’s electronic design offers insensitivity to external influences such as mechanical shock, corrosive environments, and temperature variations.
Key Features
- Adjustable range: 12.5 to 50A with rotary knob adjustment
- Class 10 tripping: Trips in 10 seconds or less at 1.2× rated current
- Phase protection: Detects and protects against phase asymmetry and phase failure
- Manual/automatic reset: Selectable reset mode to prevent nuisance trips or ensure motor safety
- Direct contactor mounting: Mounts directly to Size S3 3RT1044, 3RT1045, or 3RT1046 contactors
- Temperature compensated: Operates reliably from –25°C to +60°C with automatic compensation per IEC 60947-4-1
Technical Specifications
- Current range: 12.5–50A adjustable
- Trip class: Class 10
- Protection type: Solid-state (electronic)
- Motor protection: Three-phase AC, 50/60 Hz
- Connection method: Direct mounting on Size S3 contactors or DIN rail with separate base bracket
- Terminal type: Screw terminals (main and auxiliary circuits)
- Auxiliary contacts: NO/NC, 4A contact rating
- Operating temperature: –25°C to +60°C
- Standards: IEC 60947-4-1, ATEX 94/9/EC (increased safety EEx e)
Typical Applications
- Three-phase industrial motor protection in standard and heavy starting conditions
- Motor feeder protection in factory automation and material handling systems
- Protection of electrical loads against overload and phase failure in industrial machinery
- Integration with Siemens SIRIUS contactor-based control systems for comprehensive motor control
- Applications requiring Class 10 response and inverse-time delayed tripping characteristics
Compatibility & Replacements
Compatible With
- Siemens SIRIUS Size S3 contactors: 3RT1044, 3RT1045, 3RT1046
- Three-phase motor control circuits (50/60 Hz, sinusoidal AC networks)
- IEC-rated motor protection applications
- DIN rail or base mounting for separate installation from contactor
Replaces / Drop-In Replacement For
- Older SIRIUS 3RB2046 series units (phased-out models)
- Direct replacement for equivalent Size S3 Class 10 overload protection needs
Works With
- Siemens SIRIUS contactor control systems
- IEC 60947-4-1 compliant motor protection architectures
- Inverse-time delayed protection schemes for standard and heavy-duty motor duty cycles
- Note: For single-phase AC loads, use 3RU11 thermal relay or 3RB22/3RB23. For DC loads, use 3RU11 relays.
