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 discussing testing condenser materials, coil construction modifications, and issues with ignition at slow speeds.
| Identifier | ExFiles\Box 37\1\ scan 141 | |
| Date | 13th November 1922 | |
| Contd. -2- RL/M13.11.22. the virtues suggested in paras. 2, 3, & 4. (7) Can you test a number of suitable materials probably with a high alternating electromotive force perhaps made into a condenser form so as to find their relative values under headings, 2, 3, & 4, at all usual temperatures up to 100° centigrade. If I remember rightly you made such a test with an American Bosch condenser last year and shewed that the material used in the insulation was bade for energy losses which increased with heat. Apparently it would need a means of temperature control say by water circulation, and a means of measuring small alternating currents both in amperes and in watts. I am suggesting a modification of the method of constructing the coil. You will see in this that my views are that the L.T. wires and the volts holding down the coil are a source of loss, also the metal under the base. In conclusion we think we understand the phenomenon fairly well but we shall be pleased if you can explain how it is that the ignition becomes defective at slow speeds, because I cannot gather any reason for this failure except possibly that it may be due to the slow break allowing the breaking spark to be prolonged and so reducing the energy available. Another point I should like to prove is, is there any advantage in more highly insulating the H.T. wire and terminal instead of bringing it to the bakelite terminal. This could be easily arranged by fitting an ebonite tube | ||