Abstract
ON December 10, Mr. J. M. Kennedy, Electricity Commissioner, inaugurated the”Actadis’ system for the ripple control of the public lighting of Maidstone. This is the latest development of a method which began with the lamplighter going his rounds with his pole. The method is the distribution of high-frequency A.C. ripples over the electric supply network from a central transmitting apparatus. The high-frequency machine which generates the current injected at various points into the network is rated at 30 kilowatts, and its frequency can be varied between 300 and 900. They are injected directly on to the 6,600 volt A.C. system and actuate relays on the low-tension side. As condensers are placed in the high-frequency circuits, the power consumption is small. At present there are about 500 relays installed for the control of the lamps. The great advantage of the system is that the whole street lighting of a city can be switched on or off by actuating push buttons at a central point. If this system were adopted in a city, every street lamp could be extinguished within a few seconds of warning of an emergency being received. The system can also be used to control part of a load, for example the load required for the”water heaters', for a short time so as to prevent the maximum load, as shown by the”maximum indicator’ being exceeded. The system was installed in Maidstone by Actadis Ltd., Vincent House, Vincent Square, S.W.I. The bulk of the apparatus is manufactured in Great Britain.
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Control of Public Lighting. Nature 140, 1090–1091 (1937). https://doi.org/10.1038/1401090d0
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DOI: https://doi.org/10.1038/1401090d0