SIEMENS 3RB1262-0LB31 SIRIUS Electronic Overload Relay

The SIEMENS 3RB1262-0LB31 is a heavy-duty electronic overload relay designed for the protection of motors in high-power applications. Part of the renowned SIRIUS range, this device provides reliable protection against overheating due to overload, phase failure, or phase unbalance. It is specifically engineered to handle high current ranges from 200A up to 820A.

Precision Motor Protection

Unlike standard thermal relays, the electronic 3RB1262-0LB31 offers a wider setting range and higher accuracy. It utilizes internal current transformers to monitor the motor current accurately. The 24VDC control voltage ensures compatibility with standard PLC outputs, allowing for seamless integration into automated control cabinets.

Technical Specifications

This unit is designed for mounting onto contactors or as a stand-alone installation. It features an adjustable trip class, allowing users to tailor the protection characteristics to the specific start-up conditions of the motor. The current setting range of 200A to 820A makes it suitable for large industrial motors used in pumping stations, compressors, and heavy manufacturing lines.

System Safety and Diagnostics

The 3RB1262-0LB31 includes integrated auxiliary contacts for signaling trips to a central control system. It provides high resistance to vibration and extreme temperatures, ensuring performance in harsh industrial climates. Its low power loss contributes to overall cabinet energy efficiency, while the clear status indicators simplify troubleshooting for maintenance personnel.

Operational Advantages

One of the primary advantages of this electronic relay is its self-powered design regarding the main circuit, while the control logic utilizes the 24VDC supply. This ensures that the protection remains active even during fluctuations in the power grid. It complies with international standards such as IEC and UL, making it a globally recognized solution for motor safety.