Understanding Isolation transformers

[WiredSmart]

Hello

I found a old looking power supply in a workshop.

I would like to know if a variac can ever be a isolated transformer.




Thanks for any help in advance

[TimFox]

There are "isolated" variacs with two windings on the same toroidal core, but they are quite rare.
From the photo, it looks like the box contains a variac driving a step-down transformer to get a lower output AC voltage range.

[David Hess]

There are "isolated" variacs with two windings on the same toroidal core, but they are quite rare.
From the photo, it looks like the box contains a variac driving a step-down transformer to get a lower output AC voltage range.

The old Lionel train transformers are an example of a variac with two windings.  I have never seen a line voltage output variac with two windings, but I assume they exist.