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).
Letter to Mr. Royce discussing designs for a brake magnet, a terminal box, and the testing of porcelain insulators.
| Identifier | ExFiles\Box 180\M6\ img081 | |
| Date | 23th November 1927 | |
| -FILE- GM.231127.GC. F.H.Royce Esq., "ElmsteadHenry Royce's home in West Wittering", West WitteringHenry Royce's home town, Chichester. 23rd November 1927. Dear Mr.Royce, I am in receipt of your letter of the 19th inst; respecting Brake Magnet, and I have also received your various pencilled notes in connection with the same matter, and it is through extreme pressure of business that I have been unable to reply fully, to the different points raised. I quite clearly appreciate the help which you are giving us on this three phase brake magnet, and I freely admit that I did not quite recognise your previous intentions in regard to the bakelite flange acting as a spacer for the guides. I think matters are quite clear now, and we are at present engaged on embodying them into a final brake magnet drawing, which Iwill send at a very early date. I like your proposed design of terminal box, although I certainly have been somewhat misled by one of your earlier sketches, and the last design submitted was supposed to have been based on one of your own sketches. With regard to the different literature and samples sent, I do not want any of these returning, you are at liberty to keep the whole of the samples and the literature. I hand you herewith a couple of further prints numbers B.152 and B.153, shewing our porcelain insulators carrying mechanical ears for indoor use and for outdoor use. In connection with these insulators, we have had several of them tested by Mr.Beaver at Messrs W.T.Glover & Co.Ltd and the insulators when tested dry and having the space filled in with sulphur and glass, break down at a voltage of 8,000 Volts, and usually this breakdown seems to take place from the edge of the tapped plate to the top of the insulator. I shew the position by means of a red pencilled mark on print B.152. We are trying different filling mixtures and one that we have had filled with bitumen does not break down until 20,000 Volts has been reached, but when it does break down, it carbonizes the bitumen and remains earthed; whereas one filled with sulphur and glass does not carbonize the filling, and shews an insulation resistance of something in the neighbourhood of 20 megohms, even when it has broken down under high potential test. I have recently come across one or two other fillings for insulators, and we are experimenting with different | ||