Siemens 3RH2921-1DA02 Auxiliary Switch 2NC Lateral Screw Terminal

The Siemens 3RH2921-1DA02 is a SIRIUS lateral auxiliary switch with 2 instantaneous normally closed (NC) contacts, designed to mount on either side of 3RT2 power contactors and 3RH2 contactor relays. Screw terminals connect to both left positions (51/52, 61/62) and right positions (31/32, 41/42), with an insulation voltage of 690 V and surge voltage resistance of 6 kV.

Technical specifications:

• MLFB: 3RH2921-1DA02
• Manufacturer: Siemens
• Product line: SIRIUS
• Product type: Auxiliary switch, laterally mountable
• Contact configuration: 2 NC instantaneous contacts
• Terminal type: Screw terminal
• Insulation voltage: 690 V (pollution degree 3)
• Surge voltage resistance: 6 kV
• Operational current AC-15 at 690 V: 1 A
• Operational current AC-12 at 24/230 V: 10 A
• Operational current AC-15 at 24/230 V: 6 A
• Mechanical service life: 10,000,000 operating cycles
• Electrical endurance at AC-15, 230 V: 200,000 operating cycles
• IP rating: IP20 (front)
• Mounting: Snap-on
• Dimensions: 10 mm W x 57.4 mm H x 66 mm D
• Weight: 37 g
• Conductor cross-section: 0.5 - 2.5 mm² (solid, stranded, or finely stranded with core end processing)
• Operating temperature: -25 to +60 °C
• Compatible with: 3RT2.2, 3RT2.3, 3RT2.4, 3RH2

Features and benefits:

• Mounts on the left or right side of the contactor for flexible panel layout
• Mirror contact function per IEC 60947-4-1 when used with 3RT2 contactors
• High contact reliability: 1 faulty switching per 100 million operations at 17 V, 1 mA
• 10 million mechanical operating cycles for extended service life
• Compact 10 mm width minimises DIN rail space
• Certified for railway and maritime applications

Applications:

• Auxiliary signalling and interlocking in motor control circuits
• Status feedback on 3RT2.2, 3RT2.3, and 3RT2.4 frame contactors
• Safety monitoring circuits using the mirror contact function with 3RT2
• Industrial control panels operating up to 690 V AC

Compliant with IEC 60947-4-1 and IEC 60947-5-1. Part of the Siemens SIRIUS 3RH29 range.

Also known as: Siemens 3RH2921-1DA02, SIRIUS 3RH29 lateral auxiliary switch 2NC.