For Lightning, For Generators

Electrical-equipment manufacturers employ laboratory researchers, for the good reason that they want to find better ways of producing power, better ways of protecting power on transmission lines. One of the perennial problems of research laboratories is frictional heat in the generators. Another is the major menace to transmission lines--lightning.

>> In Pittsburgh last week the Westinghouse laboratories announced a new type of lightning recorder. Called a "fulchronograph," it gives a complete picture of a lightning stroke's intensity, from start to finish. Essential feature is a wheel with 400 iron fins on its rim, revolving at 3,400 r.p.m. A lightning arrester no bigger than a quart-size fruit jar receives the bolt, discharges it harmlessly through its coils. In these coils the lightning sets up a varying magnetic field in which the fulchronograph wheel spins. Each iron fin of the fulchronograph is magnetized according to the intensity of the field at the moment it passes through, and the result is an intensity chart of the lightning bolt every 40 microseconds (millionths of a second).

Developed by Engineer Charles Frederick Wagner and his coworkers, the fulchronograph has been tried out on top of the University of Pittsburgh's skyscraper Cathedral of Learning. The record of one bolt passing through the arrester and dissected by the fulchronograph shows that it reached a crest of 21,000 amperes, then fell rapidly (in 100 microseconds) to 1,000 amperes, and from that point more slowly to zero. From start to finish the flash lasted one-sixtieth of a second. Engineer Wagner intends to acquire a complete gallery of different types of bolt, then redesign the arresting equipment on transmission lines in accordance with what he learns.

Previous-lightning measurement has relied mainly on the oscillograph, which records the changing intensity of a bolt by means of an oscillating electron beam playing on photographic film. The fulchronograph is not only cheaper to use, says Westinghouse, but furnishes a clearer lightning picture.

>> General Electric researchers, who for years have studied lightning bolts striking Manhattan's Empire State Building, showed more interest last week in hydrogen-cooling for generators at the powerhouse. Since hydrogen is the lightest of all gases, it circulates with much less friction than air. As a result of cooling generators by hydrogen rather than air, the power output per pound of fuel is increased by 20%, and the fuel saving on a 200,000-kilowatt unit tots up to $20,000 a year. There is no fire or explosion hazard, because oil seals keep the hydrogen purity in the cooling chamber above 98%, and hydrogen will not ignite without more of an air mixture than that.

The first hydrogen-cooled generator got into action at Dayton, Ohio less than two years ago, but G.E. has now installed nine units, with a combined output of more than a half-million kilowatts. There have been no "outages" or shutdowns on these through failure of the hydrogen-cooling system.

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