The Siemens 3RU2126-4CB0 is a high-performance thermal overload relay from the trusted SIRIUS 3RU2 Series, engineered to provide reliable protection for three-phase motors against overload conditions, phase failure, and prolonged overcurrent operation. The relay features an adjustable current setting range of 17–22 A, Class 10 tripping characteristics, and is designed for direct mounting on Siemens Size S0 contactors, making it ideal for industrial motor control and automation applications.
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 prevent motor overheating, insulation damage, and premature motor failure while allowing normal motor starting currents. Integrated phase-failure sensitivity enhances motor safety and operational reliability.
The Variant CB0 provides an adjustable overload release setting of 17–22 A, making it suitable for protecting motors used in pumps, compressors, conveyor systems, fans, HVAC equipment, packaging machinery, machine tools, and industrial automation installations. Its compact S0 frame size allows efficient integration into motor starter assemblies and control panels.
The relay includes 1 Normally Open (NO) and 1 Normally Closed (NC) auxiliary contact and supports both manual and automatic reset modes, providing flexibility for signaling, monitoring, and control applications. Screw-type terminals ensure secure electrical connections and simplified installation. The relay is rated for applications up to 690 V AC.
Manufactured according to Siemens' stringent quality standards, the 3RU2126-4CB0 delivers dependable long-term performance in demanding industrial environments where continuous motor protection is essential.
| Specification | Details |
|---|---|
| Product Name | Thermal Overload Relay |
| Part Number | 3RU2126-4CB0 |
| SKU | 3RU2126-4CB0 |
| Brand | Siemens |
| Product Family | SIRIUS 3RU2 |
| Product Type | Motor Protection Relay |
| Variant | CB0 |
| Current Setting Range | 17–22 A |
| Relay Size | S0 |
| Trip Class | Class 10 |
| Operating Principle | Thermal |
| Mounting Type | Direct Contactor Mounting |
| Main Circuit Connection | Screw Terminal |
| Auxiliary Circuit Connection | Screw Terminal |
| Auxiliary Contacts | 1 NO + 1 NC |
| Reset Type | Manual / Automatic |
| Rated Operational Voltage | Up to 690 V AC |
| Number of Main Poles | 3 |
| Protection Features | Overload & Phase Failure Protection |
| Application | Industrial Motor Protection |
| Manufacturer | Siemens |
No reviews yet.