Siemens 3RH1921-1JA11 SIRIUS Auxiliary Switch Block, 1 NO + 1 NC, Lateral Side Mount, Screw Terminal, For 3RT1 Contactors Original Brand New

Product Overview

The Siemens 3RH1921-1JA11 SIRIUS Auxiliary Switch Block is a high-quality, reliable accessory designed for extending the signaling and control capabilities of your industrial contactors. This lateral (side-mounted) auxiliary switch features a 1 Normally Open (NO) and 1 Normally Closed (NC) instantaneous contact configuration, making it a versatile component for complex control circuits and feedback loops. It is specifically engineered to seamlessly integrate with the Siemens SIRIUS 3RT1 Contactor series in sizes S3 to S12. The robust screw terminals ensure secure and reliable wiring connections in demanding industrial environments.

Key Benefit

• Expanded Control: Instantly adds two auxiliary contacts (1 NO and 1 NC) to your main contactor, dramatically increasing your control and monitoring options.
• High Reliability: Part of the proven Siemens SIRIUS modular system, offering exceptional mechanical (10 million cycles) and electrical (200,000 cycles at $230\text{ V AC-15}$) service life.
• Easy Installation: Designed for tool-free, snap-on lateral (side) mounting to compatible 3RT1 contactors, minimizing installation time and effort.
• Versatile Compatibility: Ideal for use with 3RT1 Motor Contactors, contactor relays, and power contactors across various sizes (S3 to S12).
• Secure Connection: Utilizes robust screw terminals, accommodating a wide range of conductor cross-sections for a secure and durable electrical connection.

Technical Function

The 3RH1921-1JA11 auxiliary switch is an instantaneous switch block. When mounted on a compatible 3RT1 power contactor or contactor relay, it mechanically tracks the state of the main device.

• When the main contactor is energized and the main contacts close, the $1\text{ NO}$ auxiliary contact closes and the $1\text{ NC}$ auxiliary contact opens.
• When the main contactor is de-energized and the main contacts open, the $1\text{ NO}$ auxiliary contact opens and the $1\text{ NC}$ auxiliary contact closes.

This immediate signaling is essential for interlocking circuits, status indication lights, PLC/DCS input signals, and control logic applications.

For more innovative electrical control products and accessories, visit our full catalog at turll.