Siemens 3RH2921-1DA02 Lateral Aux Switch Block 2NC SIRIUS Original Brand New

Overview: Siemens 3RH2921-1DA02 SIRIUS Lateral Auxiliary Switch Block, 2 NC

The Siemens 3RH2921-1DA02 is a high-quality, reliable lateral auxiliary switch block designed for seamless integration with the SIRIUS series of control devices, specifically the 3RT2 power contactors and 3RH2 contactor relays. This snap-on accessory provides additional switching capability, crucial for complex control circuits and feedback loops in industrial automation applications.

It features two Normally Closed (2 NC) instantaneous contacts and is designed for lateral (side) mounting on the compatible base unit, ensuring a compact and secure fit. The wiring is easily managed via robust screw terminals. This block extends the functionality of your contactor or contactor relay, offering essential feedback for monitoring and safety circuits.

Benefit

1. Reliable Control Circuit Extension: Provides two independent NC contacts for crucial interlocking, signalling, or control functions.
2. Space-Saving Design: The lateral, snap-on mounting minimizes panel space requirements compared to larger, dedicated control relays.
3. High Compatibility: Perfectly matched for the widely used Siemens SIRIUS 3RT2 contactors and 3RH2 contactor relays, simplifying selection and inventory.
4. Robust and Durable: Features a high mechanical service life (10 million cycles) suitable for demanding industrial environments.
5. Easy Installation: Quick and tool-free lateral snap-on mounting and secure wiring via familiar screw terminals.

Function

The 3RH2921-1DA02 auxiliary switch is used to monitor the operational status of the main contactor or contactor relay. When the coil of the coupled main device (3RT2/3RH2) is energized, the auxiliary contacts immediately change their state:

• NC (Normally Closed) Contacts: Open when the main device is energized, and close when it is de-energized.

These signals are essential for:

• Interlocking: Preventing simultaneous activation of opposing circuits (e.g., in reversing contactor assemblies).
• Indication/Signaling: Providing remote status feedback (e.g., "Contactor OFF" light).
• Sequential Control: Activating the next step in a control sequence once the main device is de-energized.

For more of our products, technical documentation, and competitive pricing, visit turll.