Complex problem to solve - make AC power from 12V using a static inverter and take the AC produced and rectify it to 48V DC -
The first part can be done with proprietary off the shelf products - the second stage may need bespoke construction.
Attention will need to be paid to the power levels expected - the Wattage of the 48V motor should be matched at each preceding stage.
It might be easier to buy a 12V motor or a mains motor and an inverter.
Good luck...
Peccavi, April 2010
