The Siemens 3RU2136-4RB0 is a premium thermal overload relay from the SIRIUS 3RU2 Series, designed for reliable protection of three-phase motors against overload conditions, phase failure, and excessive temperature rise. The relay features an adjustable current setting range of 70–80 A, Class 10A tripping characteristics, and is designed for contactor mounting with Siemens Size S2 contactors.
Built on Siemens' proven thermal protection technology, the relay provides inverse-time delayed overload protection, helping prevent motor winding damage caused by prolonged overload conditions. It continuously monitors motor current and trips when abnormal operating conditions occur, reducing downtime and extending motor life.
The 3RU2136-4RB0 supports both manual and automatic reset modes, allowing users to configure motor protection according to application requirements. The relay includes 1 NO + 1 NC auxiliary contacts for signaling and control integration, making it suitable for modern motor starter assemblies and industrial automation systems.
Designed with screw-type main and auxiliary terminals, the relay ensures secure wiring and dependable operation in demanding industrial environments. Its compact S2 frame size enables seamless integration into MCC panels, switchboards, and motor control systems.
As part of the Siemens SIRIUS modular system, the relay is widely used in pumps, compressors, conveyor systems, HVAC installations, manufacturing equipment, water treatment plants, and process automation applications where dependable motor protection is essential.
| Specification | Details |
|---|---|
| Product Name | Thermal Overload Relay |
| Part Number | 3RU2136-4RB0 |
| SKU | 3RU2136-4RB0 |
| Brand | Siemens |
| Product Family | SIRIUS 3RU2 |
| Product Type | Motor Protection Relay |
| Variant | RB0 |
| Current Setting Range | 70–80 A |
| Relay Size | S2 |
| Trip Class | Class 10A |
| Operating Principle | Thermal |
| Mounting Type | Contactor Mounting |
| Main Circuit Connection | Screw Terminal |
| Auxiliary Circuit Connection | Screw Terminal |
| Auxiliary Contacts | 1 NO + 1 NC |
| Reset Type | Manual / Automatic |
| Rated Voltage | Up to 690 V AC |
| Protection Features | Overload & Phase Failure Protection |
| Protection Degree | IP20 |
| Application | Industrial Motor Protection |
| Manufacturer | Siemens |
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