If it has two stator coils they might be rewired for 12, or if it is just one then maybe rewind it with twice as much wire (smaller diameter of course).
Also, it is AC, coming out of the stator so you can cobble together a transformer too, or a couple of dissected and backwards wall warts to ramp up the voltage. You need a combination of transformers that would add up to ~55 volts, put all the secondaries in series, call them the primaries, and put the primaries in parallel (and in phase) and call them the secondaries and rectify that.
