Solid-state relay, 1-phase 3RF2 Width 22.5 mm, 20 A 48-460 V / 110-230 V AC Ring cable connection Solid-state relay SIRIUS 3RF21 for switching resistive/inductive loads, e.g. radiators or valves in a bottling plant. The devices switch wear-free and silently and are therefore ideal for noise-sensitive areas (offices, hospitals). They are extremely reliable even at high switching frequencies. The compact design saves space on the cooling surface. The solid-state relays can also be expanded for a wide range of applications by simply clicking on the standardized 3RF29 function modules. The devices are approved worldwide (e.g. IEC and UL/CSA). The solid-state relays are available as 1-phase devices in two widths or as 3-phase devices. They are available for various outputs and rated operating voltages. Designed for AC or DC operation, they are available with screw, spring-loaded or ring cable lug connections. In addition to the 3RF29 function modules, control plugs and terminal covers are also available as accessories. Simple, efficient, always up-to-date - the SIRIUS modular system.