MARVELS OF RADIO

New Zealand Times, Volume LI, Issue 12007, 9 December 1924, Page 9

MARVELS OF RADIO

“THE OPEN SESAME” OPERATES LIGHT AND POWER STATION FOR A CITY. VOICE CONTROLS'' SWITCHES. The “Open Sesame.” wfrich Aii Baba used to open the den of Fortv Thieves, is rivalled in the use of hiuh frequency radio waves to control and ODsrate from a distant point entirely without attendants, a complete tteotrical station, at Tipton near India lwpolis. U.S.A., supplying all the light and power requirements of a city of 10.001) person s. Through the special designing of a system of selector relays to operate with the automatic duplex carrier current telephone receiver alreadv installed at the station, the feat which mates new electrical and radio history was accomplished recently. In order to insure that the electrical supply will be without interruption. two transmission lines from different sources of power are used —the Kokomo and Noblesville power plants, respectively. If either of these transmission lines should become interrupted by reason of electrical storms, tbo supply can be resumed immediately from the alternative source. Heretofore. the operation of the oil switches to change over the source of supply ha 3 necessitated the constant presence of sub-station attendants, who have received their instructions for operating the sir itches by long distance telephone. TELEPHONE VULNERABLE TO ELEMENTS. Telephone systems, however, are even more vulnerable than power lines to the action of the elements, and power companies in the past have been unable sometimes to render continuous service during storms. The engineers of the Northern Indiana Company have felt that present day requirements of olectrical supply demanded standards of continuity higher than have been possible heretofore. The present sub-station at Tipton, the operation of which is governed entirely by high frequency waves, is the result of their efforts, and this 'new station marks a new ora in electrical development. CIRCUIT BREAKERS OF 73.000 VOLTS. The station is controlled by two massive oil circuit breakers of 73,C00 volts, 400 ampere rating, and a rupturing capacity of one and one half kilovolt amperes. These circuit breakers are connected to the transmission lines, one from the north, and the other from the south. If either of these lines develops any trouble, it is instantly observed on the power house instrument at Kokomo. In this event the Kokomo operator immediately sends, out a series of high frequency waves which opens up the oil switch at Tipton, connected to the defective line and closes the oil. which is .Connected to the reservo line, the entire operation being completed in a few seconds. METHOD OF OPERATION.' The method by which this is accomplished is as follows : The operator at Kokomo dials a certain number on a telephone of special design similar to an automatic telephone. This telephone dial is connected to a radio transmitter, and the action of dialing sends out a series of modulated radio. impulses to the antenna at Kokomo. Upon receiving these impulses, the antenna af the Tipton station leads them down to a five tube radio receiving set „nd amplifier, where they are multiplied in volume while still retaining their form characteristics. They are then carried to a series of selector relays, which in. turn operate the storage battery switches which actuate the oil circuit breaker mechanism. A special wavelength, entirely outside the broadcasting range, is used, and the series of impulses is as complex as the combination lock of a safe, and in no way subject to extraneous influences. The tests just completed have demonstrated that the apparatus works with infallible accuracy. CONTROLLED BY &UMAN VOICE. Notwithstanding the massive nature of thq apparatus which is controlled by this infinitesimal fores, the teste have shown that instead of dialing a number with the finger, tho radio controlling apparatus is so sensitive that the oil circuit breakers could be actuated by the human voice, and that the modulation could be so arrangod that tho feat of Ali Baba in opening the cave by the words, “Open Sesame,” could be duplicated. It would- be possible actually to adjust the apparatus so that the .operator at Kokomo need only say the words, “Open, circuit breakers, ’ ’ and the breakers, 25 miles away, would open.