Siemens sirius 3rt19 contactor and 3rh19 din rail control relay siemens 3rh1911 1fa22 the siemens sirius din rail auxiliary relay 3rh1911 1fa40 has screw connections and is ideal as a contactor relay or power contactor the relay has 2 no 2 nc contacts and is size s00 siemens 3rh1911 1fa22 auxiliary switch block din en50005 2no2nc s00