Ive been thinking about how transformers work and have a very simple idea.
In a regular transformer, the primary and secondary are always placed so that their fields work against one another.
Primary EMF ----> <---- Secondary EMF
As a result the secondary's emf fights the current in the primary, requiring more current to be used depending on the load in the secondary.
Why cant we place the primary inside of the secondary's wire?
http://web.tradekorea.com/upload_file/prod/marketing/mkt_files/new_company//amnet/img_en/o_P299420.jpg (http://web.tradekorea.com/upload_file/prod/marketing/mkt_files/new_company//amnet/img_en/o_P299420.jpg)
Then as long as the wire is coiled very loosely with alot of spacing between winds (so the field lines of the primary winds do not interact with each other), then the emf produced by the secondary should create a current in the primary which is of the same direction as the primary's origional current. And no additional current would need to be applied for additional load on the secondary.
Im sure it cant be as simple as this,. so please fire away so I can better understand phsyics!