FOR BOULDER DAM

Evening Post, Volume CXX, Issue 136, 5 December 1935, Page 28

FOR BOULDER DAM

NEW POWER LINE

A. made-to-measure "harness" to handle an unprecedented load of Boulder Dam electric energy—soo,ooo horse-power—has been designed.' in, a Stanford University laboratory- at Palo Alto, by engineers who Ventured into uncharted fields to test its mettle (says the "Christian Science Monitor"); The engineers were called upon to design a power line that would carry this load safely and with a minimum of waste from the dam to Los' Angeles, 275 miles. A voltage of 285,000 was specified. No other power line known to the engineers had a voltage of more than 220,000. None was known to carry so much horse-power such a distance. Electricity at 285,000 volts pressure is notoriously capricious. It will jump a 30-inch gap. Some of it will disappear into the atmosphere. Confronted with these problems, Los Angeles engineers went to the laboratory where Harris J. Ryan began experimenting with high voltage electricity more than twenty-five years ago. They built an experimental line, which'accommodated 285,000 volts butonly a microscopic fraction of the horse-power they sought to tame. They ran it through a big steel tank in which desert aridity and mountain dampness were duplicated. "Electricity under the voltage specified is virtually chain lightning," said Dr. Joseph S. Carroll, head of the laboratory. "It is highly useful when tamed, but otherwise erratic and destructive." | It was found that a line measuring 1.4 inches was the proper diameter; To save metal, the conductor was made of interlocking flat strips of copper, like countless little hinges hooked together in tandem. The line proved flexible, and able to carry the excessively high voltage with a minimum of loss. Resistance effect of the 275 miles of line knocks 10,000 volts off the potential output emerging at the end of the line. The electrical engineers used a string of twenty-four insulators in a series, making a total length of ten feet. The steel towers will be 109 feet, high and 64 feet wide at the cross arms, with the conductors 80 feet from the ground. Towers will be spaced about 1000 feet apart. _ .