What it is and what it does
The Siemens 3VU9138-1AA14-0RE0 is a remote operator mechanism for the 3VU13 series of manual motor starters and disconnect switches. It lets you open or close the 3VU13 switch from a panel door or a remote station, rather than reaching into the enclosure. The coil is rated for AC 50/60 Hz at 220-240 V.
Where it fits
This mechanism mounts onto the front of a 3VU13 switch. The panel builder wires the 220-240 V AC control circuit to the mechanism's coil terminals; the mechanical linkage then operates the switch rotary handle. It is a common fit for motor disconnect enclosures where the operator needs to be on the outside of the cabinet.