William Oh is general manager of Electro Static Technology. He has extensive design and application experience in both automation and product development, specializing in the mitigation of unwanted electrical currents. A member of the Illinois Tool Works Patent Society, he holds degrees in mechanical engineering from Pusan National University and the Korean Advanced Institute of Science and Technology. He also spent three years as a visiting researcher at the University of Massachusetts.
Today, the challenge facing system designers and engineers is to minimize damage to ac motors from shaft current. A VFD induces destructive voltages that build up on the motor shaft until they find discharge paths to the frame.