Rotating Machinery Protection Using Metal Oxide Arresters

Metal oxide arresters are ideal for the protection of rotating machines against overvoltages. The absence of gaps, required in older silicon carbide arresters, results in more consistent operation and improved protection for fast-front surges. Also, the absence of gaps permits tailoring lower voltage arrester ratings to match the application of rotating machinery. The application of arresters along with the use of surge capacitors is discussed, to limit both magnitude and rate of rise of surge voltages, for the protection of sensitive insulation systems on a variety of medium voltage systems.