Part identity and class
The ABB 1SAZ721201R1051 is catalogued as a Solid State Overload Relay, sitting under Circuit Breakers, Fuses & Protection › Relays in the same line that holds electromechanical and solid-state motor protection devices. Solid-state overload relays of this class replace the bimetallic strip in a conventional thermal overload with an electronic current-sensing and trip element, so the cubicle builder gets a tighter, adjustable trip class and a clean auxiliary output back to the contactor coil and the PLC.