Stromag Series 51 Limit Switches

Series 51 geared cam limit switches are universal, mechanical switchgear that can map a wide range of shaft rotations to the angular displacements of the installed cam discs. These cam plates actuate the mechanical switching contacts. They are used where angles or distances cannot be limited directly by switchgear, but only indirectly on the basis of the measured angle of rotation.
One classical example of this application involves limiting the hook lift of a crane hoist.