Siemens 3RH1921-1DA11 Auxiliary Switch Block, 1NO + 1NC, Side-Mounted

The Siemens 3RH1921-1DA11 auxiliary switch block is a high-quality switching component engineered for seamless integration with industrial contactors. Designed for side-mounting, this unit expands the functionality of your control system by providing one normally open (NO) and one normally closed (NC) contact. It is manufactured to meet rigorous DIN EN 50012 standards, ensuring consistent performance and safety in demanding electrical automation environments.

Advantages

This auxiliary switch block offers exceptional reliability and ease of installation for complex control circuits. By mounting directly to the side of the contactor, it saves valuable space within control cabinets while providing essential feedback and interlocking signals. The robust construction ensures long-term durability, making it an ideal choice for maintaining stable operations in industrial settings where precise switching is required.

Suitable for

• Industrial automation control systems
• Electrical interlocking circuits
• Signaling and status monitoring applications
• Motor control centers

This component may not be suitable for applications requiring high-current switching, as it is designed specifically for control-level signals. It is also not compatible with contactors that do not support side-mounted auxiliary blocks or those outside the specified series compatibility range.

Key specifications

• Contact configuration: 1 NO (Normally Open) and 1 NC (Normally Closed)
• Mounting type: Side-mounted
• Standard compliance: DIN EN 50012
• Application: Industrial control and signaling

To install the auxiliary switch block, ensure the main contactor is disconnected from the power supply. Align the switch block with the designated side-mounting interface on the contactor and snap it into place until it is securely locked. Verify that the mechanical linkage is correctly engaged before restoring power to the system.

What to consider before purchase

• Verify compatibility with your specific contactor model series
• Ensure sufficient space is available on the side of the contactor within the control panel
• Confirm that the contact configuration meets your circuit requirements

Always perform a functional test of the auxiliary contacts after installation to ensure they trigger correctly in response to the main contactor state. Ensure all wiring connections are tightened to the manufacturer's specified torque to prevent loose contacts.