Siemens 3RH2911-1FC22 Auxiliary Switch Block, 2NO + 2NC, SIRIUS Original Brand New

Overview: Reliable 2NO + 2NC Front-Mounted Auxiliary Switch

The Siemens 3RH2911-1FC22 auxiliary switch block is an essential accessory from the SIRIUS modular system, designed for quick and reliable contact expansion of your control circuits. This snap-on, front-mounted unit features a versatile 2 NO (Normally Open) and 2 NC (Normally Closed) contact configuration, specifically tailored for integration with Siemens 3RT2 contactors and 3RH2 contactor relays. It’s the ideal component for demanding industrial control applications requiring synchronized signal switching.

Key Features & Technical Specification

This compact and robust auxiliary switch is identified as 22 U and is equipped with reliable screw terminals for secure wiring.

• Contact Configuration: 2 NO (Normally Open) + 2 NC (Normally Closed)
• Switching Operation:
  • Leading NO Contacts: (1 NO + 1 NO) close before the main contacts (Terminals: .7/.8)
  • Lagging NC Contacts: (1 NC + 1 NC) open after the main contacts (Terminals: .5/.6)
• Mounting: Simple and secure front snap-on mounting (Tool-free installation).
• Compatibility: Directly suitable for SIRIUS 3RT2 power contactors and 3RH2 contactor relays.
• Connection Type: Reliable Screw Terminals.
• Identification Number: 22 U
• Brand/Series: Siemens SIRIUS 3RH29

Benefit

• Enhanced Control Functionality: Expand your contactor’s capabilities to include crucial control circuit signaling, interlocking, and status indication with the precise 2 NO / 2 NC setup.
• Optimized Switching Sequence: The unique leading NO and lagging NC paths (overlapping contacts) are perfect for safety-critical applications or specific sequence control where timing is essential.
• Fast & Easy Installation: The front-mounted, snap-on design allows for tool-free assembly, saving valuable time during panel wiring and maintenance.
• Industrial Reliability: Built to the high-quality standards of the Siemens SIRIUS series, ensuring a long mechanical service life (typically 10 million operating cycles).
• Secure Connection: Durable screw terminals ensure a strong, reliable electrical connection, suitable for harsh industrial environments.

Function

The 3RH2911-1FC22 auxiliary switch block is used to provide additional auxiliary contacts for signaling the switching state of a connected contactor or contactor relay (e.g., in a PLC input circuit or motor control system).

The contacts are designated with the terminal numbers .7/.8 for the two NO (leading) contacts and .5/.6 for the two NC (lagging) contacts. The “leading” and “lagging” contact behavior ensures a defined, sequential switching order relative to the contactor’s main contacts, often used for critical interlocks or time-delayed signaling.

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