Many transformers feature dual primaries (such as the one that I pointed to). Series = 220/240V; Parallel = 110/120V.
In one case, I've used a split primary transformer used in a power supply as an autotransformer to supply 240V to a floppy drive motor. Worked fine--use the series connection, but feed line voltage to the center tap and take your 240V from the far end.