Hinton Heavy Current Electricity in the United Kingdom

History and Development
1. Auflage 2013
ISBN: 978-1-4831-6020-7
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 88 Seiten

Heavy Current Electricity in the United Kingdom: History and Development focuses on the history and development of the electricity supply industry in the United Kingdom. The laws passed by Parliament, including those governing gas or other public companies supplying light by electricity, are considered, along with the nationalization of the electric power industry. This book consists of six chapters and opens with a discussion on Michael Faraday's discovery of electromagnetic induction that paved the way for the development of electric power, along with some major engineering achievements that contributed to advances in electricity generation. The next chapter looks at some of the laws enacted in Britain to regulate the use of electricity, including the Public Health Act of 1875 and the Gas Act of 1847. The debate over the merits of direct current vs. alternating current is also examined, together with attempts to remove legislative restrictions regarding the supply of electricity; Thomas Edison's establishment of Electric Light Company in America; and the emergence of the British manufacturing industry. The final chapter is devoted to the nationalization of the British electricity industry and the role played by the Central Electricity Board. This monograph will be of interest to energy policymakers as well as those in the electricity industry.

Autoren/Hrsg.

Hinton, Christopher

Leseproben

CHAPTER 1

Pre-history

Publisher Summary

This chapter provides an overview of the discovery of electromagnetic induction. The discovery of electromagnetic induction was an epoch-making discovery because, together with the earlier invention of the steam engine, it made more difference to the pattern of world life than any other discovery since the invention of gunpowder. The history of electric power is similar to that of steam engine because electricity had been in practical use for half a century before its nature was understood. However, the difference lies in the fact that the steam engine was invented and developed by engineers. Electricity, on the other hand, had been systematically studied by scientists for more than half a century before engineers had reason to be interested in its practical uses and electricity gives us the first example of the modern pattern of development, in which new technologies are conceived in laboratories and nursed by scientists before being put to work by engineers.

The epoch-making discovery

At the end of August 1831 Michael Faraday wrote in his notebook: “Have had an iron ring made (soft iron), iron round and in. thick and ring 6 in. in external diameter. Wound many coils of copper wire round one half, the coils being separated by twine and calico-there were three lengths of wire each around 24 ft. long and they could be connected as one length or used as separate lengths. By trial with a trough each was insulated from the other. Will call this side of the ring A. On the other side but separated by an interval was wound wire in two pieces, together amounting to about 60 ft. in length, the direction being as with the former coils; this side call B. Charged a battery of ten pairs of plates 4 in. square. Made the coil on B side one coil and connected its extremities by a copper wire passing to a distance and just over a magnetic needle (3 ft. from the iron ring). Then connected the ends of one of the pieces on A side with battery-immediately a sensible effect on needle. It oscillated and settled at last in original position. On breaking connection of A side with battery again a disturbance of needle. Made all the wires on A side one coil and sent current from battery through the whole. Effect on needle much stronger than before.”

Faraday was recording his discovery of electromagnetic induction. The ring is still in the Royal Institution.

Many great scientists had come near to forestalling him and one had failed to do so through pure bad luck. But it was Faraday who made the discovery and the development of electric power dates from the paper which he read to the Royal Society on 24 November 1831 describing his experiment. It was an epoch-making discovery because, together with the earlier invention of the steam engine, it made more difference to the pattern of world life than any other discovery since the invention of gunpowder.

The years of engineering leadership

But it was epoch-making in another and equally important way. The electric power industry was born of and nursed by scientists; almost every previous industrial development had been brought into the world by practical men and had grown up in the hard nursery of industrial trial and error; the scientist had only been brought in , sometimes to explain a failure, sometimes because curiosity led him to seek explanations of phenomena which were already being put to practical use.

This was certainly true of the steam engine. When, in the seventeenth century, men’s thoughts first turned to the possibility of converting heat into power they had considered using gunpowder as the heat source and this was not surprising. It is interesting to remember that when, in the Second World War, that great power-plant engineer Sir Claude Gibb, who was in charge of armament production in the Ministry of Supply, was teasingly told by the artillery experts that he knew nothing about guns, his answer was that so far as he was concerned, a gun was the simplest form of internal combustion engine that he had ever been concerned with.1 But gunpowder could not provide a practical source of industrial power and it was Papin who, in 1690, guided power-plant development into the right course. One often finds that those ideas which are of greatest importance are expressed in the clearest and most simple way; what Papin said was:2

“Since it is a property of water that a small quantity of it turned into vapour by heat has an elastic force like that of air, but upon cold supervening, is again resolved into water, so that no trace of the said elastic force remains, I concluded that machines could be constructed wherein water, by the help of no very intense heat, and at little cost, could produce that perfect vacuum which could by no means be obtained by gunpowder.” In those words he laid the foundation of steam-engine technology; engineering materials and manufacturing techniques made it impossible to use “strong steam” with safety; the early engines had to be “atmospheric” and they had to use the principle so clearly laid down by Papin.

He did not take his idea beyond the point of testing it with a little cylinder and piston in Huygen’s laboratory where he was employed. Papin’s basic idea was put into practical form by Thomas Newcomen, an ironmonger and smith who, possibly, did not know of Papin’s experiment. Newcomen’s engines had a thermal efficiency of less than 1%, which can be compared with the 38% that is achieved in large modern coal-fired power plants, but his design was a masterpiece of engineering because it kept within the limits of craftsmanship at that time. Newcomen’s engines were used without material change in design for 60 years and in 1769, when Watt patented the separate condenser, there were fifty-seven Newcomen engines working at mines in the Newcastle district alone.3

In Newcomen’s engines the steam was condensed in the cylinder so that the cylinder wall was cooled during each stroke of the piston. James Watt realised how great a loss of heat resulted from this and invented the separate condenser. With characteristic thoroughness he considered alternative methods of applying his invention, including one for a novel and complex rotary engine. It was only after careful thought that he decided that it would be best to use his separate condenser as a development of the well-tried Newcomen engine. Notice, once more, how the great engineer is successful because he is not over-ambitious-“by that sin fell the angels”. Even so, Watt’s engine could not have been a success without the development of Wilkinson’s boring mill, which was designed for machining gun barrels-an early example of the fact that progress in one field of technology is dependent on developments in other fields and that the production of armaments has often led to important advances in industrial technology.

Watt also patented the expansive use of steam but this was of limited value in his atmospheric engine and expansive working became really valuable only when Trevithick, that erratic genius, pioneered the use of “strong steam” (i.e. steam generated at pressures above atmospheric) and built the first railway locomotive. Stephenson greatly advanced the technology and in 1829 his “Rocket” set the pattern of locomotive design for the next century and was so successful that, for many years, his basic designs were used on fixed platforms as well as for locomotion.

Yet all this was done by engineers who knew nothing about thermodynamics and did not understand the nature of heat. Although Joseph Black had investigated the change of state in water and, by his work on latent heat, had provided the scientific basis for Watt’s invention of the separate condenser, it does not seem that there was any determined or continuous effort by scientists to explore the theory of thermodynamics. Heat was conceived as “a subtle, invisible, weightless fluid, passing between the particles of bodies with perfect freedom”.4 It was in this way that Sadi Carnot thought of it when he wrote his classical essay on “The Motive Power of Heat” which was published in 1824, a paper that was of outstanding importance because it introduced the idea of a “cycle” which was “reversible” if it was perfect.

It is interesting to ask oneself whether the conception of heat as a free-flowing fluid may have helped rather than hindered Carnot in arriving at those important conclusions. At the time when the steam engine was invented, the conception of heat as a fluid fitted well with previous experience. Power had previously been produced from water and from wind; both of these were free-flowing fluids. It was not illogical to think that heat, used to produce power, was another free-flowing fluid, which was no more invisible than air. Smeaton had shown that the overshot water wheel was more efficient than the undershot wheel and, in the overshot wheel, the water was let down from a high level to a low level just as, in Carnot’s ideal engine, heat was let down from a high temperature to a low temperature. Obviously the overshot wheel was most efficient if all the water entered the wheel at the highest possible level and left it at the lowest possible level. By analogy, the heat engine would be most efficient if all the heat was added at the highest achievable temperature and rejected at the lowest available...