What the line carries
The ABB 1SAZ211201R1009 sits in the Circuit Breakers, Fuses & Protection family on the Relays rail, filed as a Solid State Overload Relay under part number 1SAZ211201R1009. The class is the electronic motor-protection block that pairs with a contactor to trip on sustained overload, phase imbalance or loss, replacing the older bimetallic heaters with a solid-state sense element and a discrete set of trip classes. For a maintenance-spares buyer it is a panel-resident part: one or two ride in the cabinet next to the contactor they protect, and the whole job of the line is to fail predictably and reset cleanly when the motor pulls itself back under the curve.