< question completely reworded since people thought I was looking for appliance repair instructions >
Many "Power Transformers" are rated at 115V or 230V. It seems to be the most popular rating. See this list for an example: http://www.digikey.com/product-search/en?pv1393=61&FV=fff4000c%2Cfff8012f&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25
Here is a specific example: http://www.tamuracorp.com/clientuploads/pdfs/engineeringdocs/3FD-3XX.pdf
However, mains voltage is 120V (per leg) in the US. I'm confused that these are all rated 5V BELOW the expected mains voltage.
Is it expected that these transformers are for use with mains inputs? If so, why is the rating 5V below the mains voltage? If not, why is the rating so close to the mains level?