Abstract
IN addition to the usual source of electric power for supplying lamps and signalling devices, it is sometimes necessary, in order to safeguard life and property, to have another source of power that can be available in emergency. Such additional sources are necessary for theatres, cinemas, hospitals, and for all large buildings through which there is a continuous stream of traffic. Up to the present time, storage batteries have often been used for this purpose, but their drawbacks are their expense and the gases they develop, often necessitating the use of a large separate room. A petrol electric set has sometimes been suggested, but there is frequently difficulty in starting it after a long period of standstill. Fire risks also impose restrictions in the selection of rooms for these sets. In a recent issue of Allgemeine Elektricitts Gesell-schaft (A.E.G.) Progress, a new emergency lighting set is described which eliminates practically all these difficulties. It consists simply of a small water turbine, which can be connected to the municipal water mains and drives a direct current generator (turbinamo). The water supply to the turbine is normally cut off. Should the normal supply voltage fall for any reason, an electro-magnet ceases to act and so a cut-off device is released, and the pressure of the water in the mains opens a valve and the machine rotates. The water pressure required is anything between 3 and 6 atmos. (42.5-85 lb. per sq. in.). The lighting set has a vertical axis, and takes up very little space. It should be placed near the water supply mains. As a disturbance rarely occurs, and lasts only very little time, the cost of the water used is negligible.
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Emergency Lighting Sets. Nature 130, 54 (1932). https://doi.org/10.1038/130054c0
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DOI: https://doi.org/10.1038/130054c0