Contactor Relays (Auxiliary Contactors), 3RH2 (S00) with “Mechanically linked contact elements”, DC Coil@ - 3RH2122-1BB408K

Product Description

Siemens 3RH2122-1BB408K Auxiliary Contactor Relay – 24V DC Control Relay with Mechanically Linked Contact Elements

The Siemens 3RH2122-1BB408K Auxiliary Contactor Relay is a high-performance industrial switching device engineered for advanced control, automation, monitoring, signaling, and safety interlocking applications. As part of the globally trusted Siemens SIRIUS 3RH2 Series, this auxiliary contactor combines compact design, reliable switching technology, and mechanically linked contact elements to provide superior performance in modern industrial environments. Featuring a 24V DC coil, 2 Normally Open (2NO) contacts, 2 Normally Closed (2NC) contacts, and mechanically linked contact elements, the 3RH2122-1BB408K is ideal for control panels, machine automation, PLC systems, MCC panels, and industrial process control applications.

One of the most important features of the Siemens 3RH2122-1BB408K is its mechanically linked contact design. This technology ensures that normally open and normally closed contacts cannot simultaneously indicate conflicting switching positions. As a result, the relay provides highly reliable feedback for safety circuits, monitoring systems, machine control applications, and interlocking functions. Siemens designed this auxiliary contactor to support safety-related switching applications and positively driven operation according to international industrial standards.

The 2NO + 2NC contact configuration offers exceptional flexibility for industrial control systems. The two normally open contacts can be used for PLC inputs, machine control logic, signaling circuits, automation commands, and process control functions. The two normally closed contacts are suitable for fault monitoring, emergency shutdown circuits, safety interlocking, status indication, and alarm systems. This balanced contact arrangement allows engineers to implement advanced control logic while minimizing the need for additional switching components.

The Siemens 3RH2122-1BB408K Auxiliary Contactor operates with a 24V DC control supply voltage, making it ideal for PLC-controlled automation systems and industrial DC control architectures. Siemens specifies an operating range of approximately 0.8 to 1.1 times the rated control voltage, ensuring stable switching performance even when supply voltage fluctuations occur. The coil consumes approximately 4W, providing efficient operation without compromising switching reliability.

Designed in the compact S00 frame size, the 3RH2122-1BB408K provides excellent space utilization within automation cabinets and electrical control panels. Despite its compact dimensions, the relay delivers industrial-grade performance with operational currents up to 10A AC-15 at 230V and supports a broad range of switching applications. This combination of compact size and high performance makes it a preferred choice for panel builders, OEMs, and industrial system integrators.

The relay uses durable screw terminal connections, ensuring secure conductor retention and long-term electrical reliability. Screw terminals remain a preferred connection technology in industrial environments due to their excellent vibration resistance, ease of maintenance, and dependable electrical performance. This design simplifies installation and supports reliable operation in demanding industrial conditions.

The Siemens SIRIUS 3RH2122-1BB408K is engineered for long service life and exceptional durability. Siemens specifies a mechanical endurance of up to 30 million operating cycles, making it suitable for high-frequency switching applications. The device also features a rated insulation voltage of 690V, rated impulse withstand voltage of 6kV, and IP20 protection on the front, ensuring dependable performance in industrial environments.

As part of the Siemens SIRIUS modular platform, the 3RH2122-1BB408K Auxiliary Contactor Relay supports compatibility with a wide range of Siemens accessories, including auxiliary contact blocks, surge suppressors, and mounting accessories. This modular design enables flexible system expansion while reducing maintenance complexity and spare-parts inventory requirements.

The Siemens 3RH2122-1BB408K is widely used in PLC control panels, motor control centers (MCCs), packaging machinery, material handling systems, water treatment plants, process automation systems, factory automation projects, HVAC controls, and industrial infrastructure installations. Its combination of mechanically linked contacts, reliable 24V DC operation, and Siemens engineering excellence makes it a trusted solution for critical industrial control applications.

At SBsmart.in, we provide genuine Siemens industrial automation and control products trusted by engineers, OEMs, electrical contractors, panel builders, and industrial buyers across India. When you purchase the Siemens 3RH2122-1BB408K Auxiliary Contactor Relay, you receive an authentic Siemens SIRIUS solution designed for superior reliability, long operational life, and seamless integration into modern automation systems.