From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Report from the British Electrical and Allied Industries Research Association on hard composite insulating materials.
| Identifier | ExFiles\Box 24\2\ Scan207 | |
| Date | 21th February 1922 | |
| X 1109 DIRECTIONS FOR THE STUDY OF HARD COMPOSITE DIELECTRICS. 565 and cellular materials. The output before the war was well over one million tons. The clay is won by washing over the face of the rock with a stream of water and picking the face, and in modern plant by hydraulic mining with pressure jets. The clay and water or slip are pumped to the surface, passed over obstacles and through channels called “micas,” where the fine silica and mica are deposited. From the “micas” the slip is run into tanks where the clay is allowed to settle and finally, when in a butterlike state, it is thrown on the floor of the “dry,” where the bulk of the water is driven off by heat and the clay containing some 12 per cent of water is ready for sale. In all these four trades you will find every sort of temporary device, every kind of clever expedient used to save labour, at small capital expense because all the traders are relatively poor but the skill of the workers is great. It is a splendid field in which young engineers may study, and the fact that Cornwall and the Camborne School of Mines have sent all over the world so many skilled miners is proof of its efficiency. On these primary trades depend coal miners, rope and sail makers, ship-builders, carriers, manufacturers of agricultural and mining plant and, finally, the Electric Power Company. Before the war, as I have said, all these trades were in a fair state of prosperity; -now, owing to the failure first of tin mining and then of the export trade in china clay, all are in want. Coal is not wanted, the electric power output is reduced to a point where the Company can hardly meet working expenses, and all the subsidiary trades suffer. The failure is not, in Cornwall, due to strikes or demands for unpayable wages; the source of their woes is so clear that the men are fully seized with a rough knowledge of economics. The men were, and are, willing to work for any living wage, but there is no one to pay it. It is a grievous position and there is no very clear remedy. Until the American demand increases there can be no revival in china clay. The Americans may have gold but they do not want clay, and so the harbours are full of idle ships. The heavy taxes stop restoration because capital is wanted to re-start trade and the Government take in income and other taxes and in death duties the money, and with it the energy and boldness to face chances, that trade so badly needs. Generally speaking, the man who makes a safe investment does not really help trade; primarily he provides for his old age. The essence of trading is adventure involving risk, and that risk is carried either by the man who trades with his own money or who by investing in ordinary shares helps others to bear the risk. When we see Ordinary shares being asked for, we shall know that trade has begun to revive. I suggest that a study of the history of trade is one full of use and interest. History is taught too much as a record of rulers, of kings, of ministers and of law-makers, rather than of the traders in whose interests many of our laws were made, and in fact, many wars fought. Read of Simon de Montfort and the Wars of the Roses and the laws of Henry VII and of Stuart times in the light of trade. The histories of the city companies provide interesting and often exciting reading. The record of the lives of such men as Thomas Gresham and of Cecil Rhodes open up new fields for thought and for example in adventure and statesmanship. It is for the young men to remain students and to add to the greatness of our Empire by facing fortune and bearing the risks, aye and of winning the rewards, as in days of long ago. DIRECTIONS FOR THE STUDY OF HARD COMPOSITE DIELECTRICS (INSULATING MATERIALS). (REPORT RECEIVED FROM THE BRITISH ELECTRICAL AND ALLIED INDUSTRIES RESEARCH ASSOCIATION, 21ST FEBRUARY, 1922.) CONTENTS. Clause No. . . . . . . . . . . . . . . . . . . . . . . . . Page Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . 565 Introduction . . . . . . . . . . . . . . . . . . . . . . 566 1 Temperature Grading . . . . . . . . . . . . . . 566 2 Conditions of Test . . . . . . . . . . . . . . . . 566 3 Resistivity . . . . . . . . . . . . . . . . . . . . . . 567 4 Surface Resistivity . . . . . . . . . . . . . . . 568 5 Electric Strength . . . . . . . . . . . . . . . . 569 6 Toughness . . . . . . . . . . . . . . . . . . . . . . 569 7 Plastic Yield with Temperature . . . . . . 570 8 Cross-breaking Strength . . . . . . . . . . . . 571 9 Crushing . . . . . . . . . . . . . . . . . . . . . . . 571 10 Ageing . . . . . . . . . . . . . . . . . . . . . . . . 572 11 Density . . . . . . . . . . . . . . . . . . . . . . . . 572 12 Water Absorption . . . . . . . . . . . . . . . 572 13 Tool Wear . . . . . . . . . . . . . . . . . . . . . . 572 14 Chipping . . . . . . . . . . . . . . . . . . . . . . . 573 VOL. 60. PREFACE. This Specification defines methods of test intended for use in the investigation of the mechanical and electrical properties of hard composite insulating materials. The clauses of the Specification are not intended as “acceptance” tests in the purchasing of such materials, although developments of some of them eventually may be capable of adoption for this purpose. The methods of test have been defined only after a long series of trials, using a wide range of hard dielectrics. Materials were included having bases of vulcanized rubber, vulcanized bitumen, shellac, and synthetic resin respectively, amongst others, but the large amount of actual data collected in the course of the research is not incorporated in this Specification. 39 | ||