The Life and Letters of Sebastian Ziani de Ferranti

SUBJECT AREA: Electricity, Public utilities

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Ferranti, who had taken an interest in electrical and mechanical devices from an early age, was educated at St Augustine's College in Ramsgate and for a short time attended evening classes at University College, London. Rather than pursue an academic career, Ferranti, who had intense practical interests, found employment in 1881 with the Siemens Company (see Werner von Siemens) in their experimental department. There he had the opportunity to superintend the installation of electric-lighting plants in various parts of the country. Becoming acquainted with Alfred Thomson, an engineer, Ferranti entered into a short-lived partnership with him to manufacture the Ferranti alternator. This generator, with a unique zig-zag armature, had an efficiency exceeding that of all its rivals. Finding that Sir William Thomson had invented a similar machine, Ferranti formed a company with him to combine the inventions and produce the Ferranti- Thomson machine. For this the Hammond Electric Light and Power Company obtained the sole selling rights.

In 1885 the Grosvenor Gallery Electricity Supply Corporation was having serious problems with its Gaulard and Gibbs series distribution system. Ferranti, when consulted, reviewed the design and recommended transformers connected across constant-potential mains. In the following year, at the age of 22, he was appointed Engineer to the company and introduced the pattern of electricity supply that was eventually adopted universally. Ambitious plans by Ferranti for London envisaged the location of a generating station of unprecedented size at Deptford, about eight miles (13 km) from the city, a departure from the previous practice of placing stations within the area to be supplied. For this venture the London Electricity Supply Corporation was formed. Ferranti's bold decision to bring the supply from Deptford at the hitherto unheard-of pressure of 10,000 volts required him to design suitable cables, transformers and generators. Ferranti planned generators with 10,000 hp (7,460 kW)engines, but these were abandoned at an advanced stage of construction. Financial difficulties were caused in part when a Board of Trade enquiry in 1889 reduced the area that the company was able to supply. In spite of this adverse situation the enterprise continued on a reduced scale. Leaving the London Electricity Supply Corporation in 1892, Ferranti again started his own business, manufacturing electrical plant. He conceived the use of wax-impregnated paper-insulated cables for high voltages, which formed a landmark in the history of cable development. This method of flexible-cable manufacture was used almost exclusively until synthetic materials became available. In 1892 Ferranti obtained a patent which set out the advantages to be gained by adopting sector-shaped conductors in multi-core cables. This was to be fundamental to the future design and development of such cables.

A total of 176 patents were taken out by S.Z. de Ferranti. His varied and numerous inventions included a successful mercury-motor energy meter and improvements to textile-yarn produc-tion. A transmission-line phenomenon where the open-circuit voltage at the receiving end of a long line is greater than the sending voltage was named the Ferranti Effect after him.

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