Siemens First lateral auxiliary switch for 3RT1, 2NO, screw terminal Part number 3RH1921-1EA20

Product Overview

The Siemens 3RH1921-1EA20 is a side-mount auxiliary switch block designed for SIRIUS contactors (size S0). It includes two normally open (2 NO) instantaneous auxiliary contacts for reliable signalling, control, and feedback operations in motor starter and automation circuits. Its compact, robust construction ensures dependable operation under demanding industrial conditions.

Key Features

• Side-mount auxiliary switch block for Siemens SIRIUS contactors
• Contact configuration: 2 normally open (2 NO) contacts
• Instantaneous contact operation for accurate control response
• Screw terminal connection for secure wiring
• Compatible with S0-size contactor frames in the 3RT1 series
• Compact design allowing easy installation and durable operation

Technical Specifications

• Product Series: Siemens SIRIUS Auxiliary Switch Blocks
• Article Number: 3RH1921-1EA20
• Contact Configuration: 2 NO instantaneous contacts
• Rated Insulation Voltage (Ui): 500 V AC
• Rated Impulse Withstand Voltage (Uimp): 6 kV
• Rated Operational Current (AC-15, 230 V): 3 A
• Mechanical Service Life: 10 million operating cycles
• Electrical Endurance (AC-15, 230 V): 200,000 switching cycles
• Protection Class (Front): IP20
• Mounting Position: Lateral, left side of contactor
• Contactor Size Compatibility: S0
• Net Weight (Approx.): 0.05 kg

Compliance & Certifications

• Complies with IEC / EN 60947-5-1 standards for auxiliary switching devices
• Designed for industrial motor control and automation applications
• RoHS compliant and manufactured under Siemens quality standards

Applications

The Siemens 3RH1921-1EA20 auxiliary contact block is ideal for use in control panels, automation systems, and motor starter combinations requiring additional signalling or feedback contacts. Its high durability, simple mounting, and precise contact performance make it well-suited for continuous industrial operation.