The Siemens 3RU2136-4QB0 is a premium thermal overload relay from the SIRIUS 3RU2 Series, designed to provide reliable protection for three-phase motors against overload conditions, phase failure, and excessive current draw. The relay features an adjustable current setting range of 47–57 A, Class 10 tripping characteristics, and is designed for direct contactor mounting on Size S2 contactors.
Built on Siemens' proven thermal overload protection technology, the relay continuously monitors motor current and disconnects the motor when overload conditions persist. Its inverse-time delayed tripping characteristic helps protect motors from overheating, insulation damage, and premature failure while allowing normal motor starting currents.
The Variant QB0 incorporates a thermal overload release with an adjustable setting range of 47–57 A, making it suitable for protecting motors used in pumps, compressors, conveyors, fans, HVAC systems, manufacturing equipment, and industrial automation machinery. The relay is optimized for use with Siemens S2 contactors, enabling compact and space-saving motor starter assemblies.
As part of the Siemens SIRIUS motor protection portfolio, the 3RU2136-4QB0 supports both manual and automatic reset modes and includes 1 NO + 1 NC integrated auxiliary contacts for trip signaling and control circuit integration. These features enhance operational flexibility and simplify system monitoring.
The relay utilizes screw-type terminals for both main and auxiliary circuits, ensuring secure electrical connections and straightforward installation. With a rated insulation voltage of 690 V, surge voltage resistance of 6 kV, and an operating temperature range of -40°C to +70°C, it delivers dependable performance in demanding industrial environments.
Manufactured according to Siemens' stringent quality standards, the 3RU2136-4QB0 is widely used in motor control centers (MCCs), water treatment facilities, process industries, material handling systems, and industrial automation projects where reliable motor protection is essential.
| Specification | Details |
|---|---|
| Product Name | Thermal Overload Relay |
| Part Number | 3RU2136-4QB0 |
| SKU | 3RU2136-4QB0 |
| Brand | Siemens |
| Product Family | SIRIUS 3RU2 |
| Product Type | Motor Protection Relay |
| Variant | QB0 |
| Current Setting Range | 47–57 A |
| Relay Size | S2 |
| Trip Class | Class 10 |
| 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 Insulation Voltage | 690 V |
| Surge Voltage Resistance | 6 kV |
| Number of Main Poles | 3 |
| Operating Temperature | -40°C to +70°C |
| Protection Features | Overload & Phase Failure Protection |
| Application | Industrial Motor Protection |
| Manufacturer | Siemens |
No reviews yet.