i have experience with the opposite issue, using a UK kitchenaid in the US on transformer, but it may be relevant. i took my KA mixer to the US and bought a transformer there. (also took UK magimix food processor ) i spoke to company reps and bought recommended transformer. the ka mixerworked fine, but i did notice a difference in the way the motor sounded and it seemed to 'work harder'. (the magimix just didn't work at all after a few seconds, fyi) i have since moved back to europe, and both appliances are working fine. when i move back to the US this time, i will get rid of both of them, though, because they don't seem to do optimal work on transformer. that may have to do with the fact that the110 power source in the US was not strong enough, even with the step up function of the transformer.