Siemens 3RH2921-1DA20 Auxiliary Switch 2NO Lateral Screw Terminal

The Siemens 3RH2921-1DA20 is a SIRIUS lateral auxiliary switch providing 2 instantaneous normally open contacts for use with 3RT2 contactors and 3RH2 contactor relays. It mounts on either the left or right side via snap-on fastening and connects via screw terminals rated to 690 V insulation voltage. Rated at 10 A at AC-12 and 1 A at AC-15 at 690 V, it suits a wide range of control circuit applications.

Technical specifications:

• MLFB: 3RH2921-1DA20
• Manufacturer: Siemens
• Product line: SIRIUS
• Product category: Auxiliary switch
• Contact arrangement: 2 NO instantaneous (left 53/54, 63/64; right 33/34, 43/44)
• Insulation voltage: 690 V (pollution degree 3)
• Surge voltage resistance: 6 kV
• Operational current AC-12 (max): 10 A
• Operational current AC-15 at 230 V: 6 A; at 690 V: 1 A
• IP rating: IP20 (front)
• Mechanical service life: 10,000,000 operating cycles
• Electrical endurance AC-15 at 230 V: 200,000 operating cycles
• Contact reliability: 1 faulty switching per 100 million (17 V, 1 mA)
• Operating temperature: -25 to +60°C
• Storage temperature: -55 to +80°C
• Mounting: snap-on, lateral
• Terminal type: screw-type
• Conductor cross-section: 0.5-2.5 mm² (solid, stranded, or finely stranded with end processing)
• AWG: 20-14
• Dimensions (WxHxD): 10 x 57.4 x 66 mm
• Net weight: 37 g
• Suitable for: 3RT2.2, 3RT2.3, 3RT2.4, 3RH2

Features and benefits:

• Mounts laterally on left or right side of compatible contactors and relays without extra tools
• Mirror contact function per IEC 60947-4-1 when paired with 3RT2 contactors
• 10 million cycle mechanical service life for extended reliability in demanding environments
• High contact reliability with just 1 faulty switching per 100 million operations
• Wide operating temperature range of -25 to +60°C supports varied installation conditions

Applications:

• Expanding auxiliary contact capacity on 3RT2 contactors (sizes 2, 3, and 4)
• Adding feedback contacts to 3RH2 contactor relays
• Signaling and interlocking in motor control switchgear panels
• Safety circuit monitoring via mirror contact function with 3RT2
• Control circuits requiring DC switching up to 220 V

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

Also known as: Siemens 3RH2921-1DA20, SIRIUS 3RH29 lateral auxiliary switch.