Knowing more about the item would help.

Check to see what the appliance can handle. Eg. Some are designed to work from 110 - 250V and 50/60Hz, so they will work in both the US and Australia, with the correct plug installed, of course.

If not, a transformer is generally the easiest way to go. Remembering, if it's something involving a motor (fridge, washing machine, etc), there's the issue of frequency (US 60Hz vs. AU 50Hz) - there shouldn't be a problem apart from it running slower if plugged into an Australian power point.

You're right, a 1200W+ transformer would be a descently sized piece of kit. Could be worth buying a new appliance if it's of low value?

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TD06 - Oink.