Variac build questions

In the schematic, why is the variac only on the hot wire?

I have a powerstat open frame type variac that has four terminals. In my prior build without fuses or meters i had both the neutral and hot going into and out from the variac.

Will the powerstat work in the schematic below? Can i simply only have the hot wire going into the powerstat?

>In the schematic, why is the variac only on the hot wire?

Because the schematic is WRONG.  Don't use it. If it "works" it's only because of the Variac's increasing inductance acting as a variable resistor. I want to say more about it, but no, it's just wrong.

The Variac (and I'm pretty sure the Powerstat as well) is a variable autotransformer, and that implies how it should be wired.

I'm sure others can and will give a full complete answer and explanation of what you should do, but I'm not comfortable doing it (I'm 99.4 percent sure how to do it, but I don't know what the Variac or Powerstat terminals are labeled, and I just don't wanna, especially after seeing that thing). All I'll say is don't even think of using THAT schematic, whether with a Variac or Powerstat.

here is a variac correctly wired.

The wiring diagram doesn't seem to load now.

I'm pretty sure the OP got his questions answered on another forum (gearslutz).

JR