The United States provides three-phase voltage of 220V, and they use a single-phase voltage of 110V
So your equipment, if you use a single-phase 220V, or three-phase 380V voltage, then, to be put into the U.S. to use the must be added a step-up transformer, the U.S. three-phase 220V voltage rise Transformer, will be the United States of America's three-phase 220V voltage up to three-phase 380V in order to ensure the normal operation of the equipment
As for the frequency of 50HZ or 60HZ on the equipment is not a great impact, unless the very precise instruments.