Stepping up 240v to higher voltage.
Yes, for a short time, and then there will be a BANG and a fire will start. 

Whether that happens in 5 minutes or 5 days is based on the quality of the build of the equipment.  Siemens >> random junk off Alibaba. 

If you plan to do that, then buy a 240/480 autotransformer in the first place, which can also be used for 120/240 at half the VA.  This type is more likely to be available as an isolation transformer, for what that's worth.