an unusual frequency 40-Hz power in the early years

The early development of alternating current (ac) power systems was marked by the use of a number of different frequencies, which generally ranged from 16 2/3 Hz to as high as 133 Hz. It was found that higher frequencies were better for electric lighting while lower frequencies had advantages for operating electrical equipment such as motors, generators, and rotary converters. Over the years, much effort went into developing a single compromise frequency that would be suitable for most electrical applications. Eventually, 60-Hz power came to predominate in North America, in part of South America, and in a handful of other counties. Similarly, a standard of 50 Hz was adopted in Europe, Africa, Asia, Australia, and in the remainder of South America. Prof. Dr. Gerhard Neidhofer authored a comprehensive article on the development of the 50-and 60-Hz frequency standards that appeared in the July/August 2011 issue of this magazine. This issue's "History" article, written by Thomas J. Blalock, a frequent contributor to IEEE Power & Energy Magazine, details the promotion, chiefly by the General Electric Company, of a 40-Hz frequency standard that enjoyed some initial success but ultimately failed to displace 60 Hz as the standard frequency. Tom Blalock earned a B.S.E.E. degree from Lafayette College and an M.E.E.E. degree from Rensselaer Polytechnic Institute. His duties as a development engineer at the former General Electric High-Voltage Engineering Laboratory and later as a test engineer in the Transformer Test Department, both in Pittsfield, Massachusetts, included a broad range of duties, including lightning protection and high-voltage switching surge studies. Since retiring from General Electric, Tom has actively pursued his hobby of "industrial archaeology," with particular emphasis on the exploration, preservation, and careful documentation of historically important and interesting electric power projects and equipment. We welcome Tom back as our guest history author for this issue of IEEE Power & Energy Magazine. -Carl Sulzberger Associate Editor, History