SIEMENS 3RF2120-1AA02 SIRIUS 3RF2 Single-phase Zero-cross Solid State Relay, 20A AC-51

Overview The SIEMENS 3RF2120-1AA02 is a SIRIUS 3RF2 series single-phase semiconductor relay (SSR) with zero-cross switching. It is designed for switching resistive loads, widely stocked as spare for heating control, packaging machinery and industrial automation cabinets.

Features This module has a slim 22.5mm width, DIN rail mounting and screw terminals. The 3RF2120-1AA02 supports load voltage 24–230VAC, rated current 20A (AC-51), control input 15–24VDC. Zero-cross switching reduces inrush current and electromagnetic interference. It can be fitted with terminal covers, load monitoring modules and other accessories.

Specs Model: 3RF2120-1AA02 Series: Siemens SIRIUS 3RF21 Type: Single-phase zero-cross solid state relay Load: 24~230VAC, 20A AC-51 Control: 15–24VDC Mounting: 35mm DIN rail Width: 22.5 mm Protection class: IP20 Certifications: CE, UL, IEC 60947 Product status: active industrial spare

Principle Thyristor elements turn on at the AC voltage zero point to switch the load circuit smoothly. When the DC control signal is removed, the thyristor cuts off at the next zero crossing, avoiding electric arcs and extending service life.

Applications The 3RF2120-1AA02 is widely used for electric heater control, oven, packaging machine and HVAC control panels. It is used for frequent switching of resistive AC loads.