Siemens SIRIUS Analog Monitoring Relay (3UG4513-1BR20)
The Siemens 3UG4513-1BR20 is a high-performance, DIN-rail mounted analog monitoring relay from the premium SIRIUS line network protection series. Engineered to safeguard three-phase motors, industrial machinery, and electrical installations, this compact 22.5 mm wide device continuously supervises critical line supply parameters. It provides automated real-time protection against fatal power line errors, including phase failure (loss), phase sequence (incorrect rotation), and phase undervoltage, ensuring unstable supply conditions are isolated before causing severe hardware damage or system downtime.
Key Features
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Multi-Parameter 3-Phase Monitoring: Delivers comprehensive safety screening by evaluating phase sequence, detecting total phase failure, and tracking line undervoltage conditions.
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Adjustable Threshold & Tripping Delay: Features front-facing analog potentiometers allowing technicians to configure an absolute undervoltage window between 160V and 690V AC, paired with a customizable time-delay adjustment spanning 0.1 to 20 seconds to avoid nuisance tripping.
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Self-Powered Operation: Draws its operational power directly from the measuring circuit ($L1, L2, L3$), eliminating the need for a separate, external auxiliary power source.
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Dual Changeover Contacts (2 CO): Outfitted with two independent changeover relay contacts, facilitating simultaneous interlocking control over motor starter contactors and remote HMI alarm annunciators.
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Intuitive Diagnostic Status LEDs: Includes front-mounted diagnostic LEDs providing immediate physical indication for operational status, phase sequence faults, and phase loss.
Technical Specifications
| Feature | Specification |
| Model / Reference | 3UG4513-1BR20 |
| Brand / Family | Siemens / SIRIUS |
| Product Type | Three-Phase Network Monitoring Relay |
| Monitored Parameters | Phase Sequence, Phase Loss, Undervoltage |
| Adjustable Voltage Range ($U_e$) | 160V to 690V AC (50/60 Hz) |
| Tripping Delay Time | Adjustable from 0.1 to 20 seconds |
| Output Contacts Configuration | 2 CO (Changeover contacts / SPDT) |
| Electrical Connection | Standard Screw Terminals |
| Housing Design Width | 22.5 mm (Space-saving profile) |
| Mounting Type | Standard 35mm DIN Rail |
| Standards & Certifications | IEC/EN 60947-1, UL Listed, CSA, CE Marked, CCC Approved |
Applications
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Industrial Motor & Pump Protection: Safeguarding high-value compressors, conveyor drives, and hydraulic pumps from overheating due to single-phasing or running in destructive reverse rotation.
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HVAC Chiller & Fan Systems: Protecting large refrigeration compressors and industrial ventilation fans from spinning backward and causing mechanical hardware damage.
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Mobile Power Generation & Rental Plants: Providing automated grid verification for portable generators, mobile equipment networks, and construction site power distribution boards.
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Automated Material Handling: Serving as an essential supply-line safety interlock for multi-axis overhead cranes, passenger elevators, and sorting conveyor systems.
