The Overload Relay is a three element bimetallic device that actuates a built-in SPDT switch when any one of the elements is overheated. The relay can be easily adjusted to trip within a range of 1.2 A to 2.1 A by turning the calibrated dial on top of the unit.

The bimetallic elements have a built-in time delay function preventing nuisance tripping during motor starting. A cooling off period is required after tripping, before the relay resets itself. The SPDT contacts are rated for 10 A continuous duty.