Abstract
ANYTHING that will cheapen the cost of the electrification of our railways deserves serious study at the present time. In the United States, a continually increasing number of automatic sub-stations are being employed in electric traction. It is interesting, therefore, to notice that in the extension of the London Electric Railway from Hendon to Edgware, which opened for traffic on August 18, there is a completely equipped automatic sub-station. Although there are several of these stations in Great Britain in connexion with lighting networks, this is the first to be used for traction purposes. The building has been designed for three 1200-kilowatt rotary converters with all the necessary control gear and accessories. The sub-station gets a 10,500-volt three-phase supply from the Lots Road Generating Station at Chelsea, the frequency being 33-J. It is situated at Burnt Oak, which is one mile from the Edgware terminus and four miles from the manually operated substation at Golder's Green. To start a rotary converter at Burnt Oak, it is only necessary to close a switch at Golder's Green, all the subsequent operations being automatic. Cooling air for the transformers is supplied by a centrifugal blower. The automatic devices protect the machines in all conditions of overload. For example, when the load is too heavy, the circuit breaker opens and a resistance is inserted in the machine circuit and the rotary is disconnected from the supply mains. After a short interval the circuit breaker closes again and connexion is re-made. If the fault has been cleared, normal operation is resumed, but if not, the same sequence of operations happens again. If this happens a fixed number of times, the breaker is automatically locked and an engineer must be sent to investigate and remove the fault.
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Current Topics and Events. Nature 114, 287–290 (1924). https://doi.org/10.1038/114287a0
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DOI: https://doi.org/10.1038/114287a0