How to use SSR (diagram)

I am buying this SSR to control a 0.75 220 /v motor but the diagram supplied (attached) confuses me. Shouldn’t the load be connected back to the negative side of Vin? Why isn’t it?

Terminals 1 and 2 are the output, 3 and 4 the input. This is an AC operated SSR, the diagram shows the load switched via 1 and 2 but you are right, the return from the load is wrong.

This seems to be another diagram for it

The power supply for your motor or other load goes on the right hand side of this drawing.

The alternating current symbol on the left hand side of the drawing is your low-current AC control signal.