Today I was have a look of my pictures of this project, them stored at my hard drive.
Two questions seems that they were never answered with enough clarity.
1) What is the manufacturing decade of the Powerstat 226U which I received from Italy?
Due a sticker over it body this mentioning patents and dates, I can safely assume that this is production of 1972 ~ 1980 especially for export to EU.
The knob shape over my Variac, this is extremely unique.
2) The only consumable of this transformer, this is a single carbon brash.
Part description: Superior Electric RB226
Superior Electric firm in the USA, this is still alive, and I did spot on eBay an Powerstat 226U, this be production of 2015.
I did some thoughts because of the high cost of my project, if it worth having and a spare carbon brash (Superior Electric RB226)?
My transformer came as new (never used) old stock, and up to date, this was never stressed by my hands.
Therefore it is wise of me, so to avoid this unnecessary expense for now.