Siemens 3RH1921-1CA10 SIRIUS Auxiliary Switch 1NO Front Screw Terminal

The Siemens 3RH1921-1CA10 is a SIRIUS front-side auxiliary switch with 1 NO instantaneous contact and screw terminals, designed to snap onto the front of 3RT1 contactors. It operates at up to 690 V AC insulation voltage with 6 kV surge voltage resistance and IP20 front protection. Mechanical service life reaches 10,000,000 operating cycles with a contact reliability of 1 faulty switching per 100 million operations at 17 V / 1 mA.

Technical specifications:

• MLFB: 3RH1921-1CA10
• Manufacturer: Siemens
• Product line: SIRIUS
• Contact arrangement: 1 NO instantaneous contact
• Insulation voltage: 690 V AC (pollution degree 3)
• Surge voltage resistance: 6 kV
• Operational current at AC-15, 690 V: 1 A
• Operational current at AC-12: 10 A max
• IP rating (front): IP20
• Mechanical service life: 10,000,000 operating cycles
• Electrical endurance at AC-15, 230 V: 200,000 operating cycles
• Compatible contactors: 3RT10, 3RT12, 3RT145, 3RT146, 3RT147
• Mounting: snap-on to front of contactor
• Terminal type: screw-type
• Conductor cross-section: 0.5 to 2.5 mm² solid/stranded; AWG 20 to 14
• Dimensions (W x H x D): 10 x 38 x 51 mm
• Weight: 19 g
• Operating temperature: -25 to +60 °C

Features and benefits:

• Mirror contact function per IEC 60947-4-1 enables safety-critical status monitoring with 3RT1
• Front snap-on mounting allows tool-free addition to installed contactors without rewiring
• 10,000,000-cycle mechanical service life for long-term use in high-frequency switching applications
• Wide operating range of -25 to +60 °C suits demanding industrial panel environments
• Compact 10 mm width minimises space consumption in control panel assemblies

Applications:

• Safety monitoring circuits requiring verified mirror contact status on 3RT1 series contactors
• Auxiliary signalling and interlocking in motor starter assemblies
• Contactor status feedback in industrial automation and control panels
• Front-accessible auxiliary switching on 3RT10, 3RT12, 3RT145, 3RT146 and 3RT147 contactors

Compliant with IEC 60947-4-1 (mirror contact) and referenced against IEC 60947-5-1. Part of the Siemens SIRIUS 3RH19 range.

Also known as: Siemens 3RH1921-1CA10, SIRIUS 3RH19 auxiliary switch, Siemens front auxiliary contact block.