I ran across the diagram below in the [mindtomachine blog](https://i.stack.imgur.com/fvlRy.png) post describing an homebrew arc welder. It shows two transformers with inputs in parallel and outputs in series. Is there some advantage to this arrangement rather than a single transformer with a doubled turns ratio?

Perhaps it's just what he had at hand, but I wanted to confirm with someone having EE background. 

[![Welder Circuit](https://i.stack.imgur.com/5a829.png)](https://i.stack.imgur.com/5a829.png)

P.S. I'm *not* planning on building this, just curious.