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).
The construction and testing of an ignition coil without ballast, including tabulated results from a six-hour run.
| Identifier | ExFiles\Box 61b\4\ scan0146 | |
| Date | 26th October 1927 guessed | |
| 2 This sheet is split up from each end for a distance of 1-1/4", the slits being spaced 1/8" apart and the strips thus formed, are twisted through 30° approx. It would seem that the original intention was to fold these flexible frills around the ends of the coil and thus make a more or less closed magnetic circuit, but this has not been done. The inside end of the secondary is connected to the high tension terminal on the top of the coil, the outside end of the H.T. is connected to the inside end of the primary and both taken to a L.T. terminal. The only cause of failure in our experience, has been the break-down of the insulation between this L.T. terminal and the H.T. terminal. The outside end of the primary is connected to another L.T. terminal. The three terminals are on the top of the coil, the H.T. in the centre protected by a tall sleeve of Bakelite which is moulded solid with the cap. The two L.T. terminals are arranged symetrically on either side of the central (H.{Arthur M. Hanbury - Head Complaints} T.) terminal. RE: IGNITION COIL WITHOUT BALLAST Below are the figures which we have obtained on a six hour run, with the coil connected across the terminal of a six volt battery, to which was connected a Westinghouse regulated generator. The readings are taken at intervals of 30 mins. TIME CURRENT TEMP VOLTS ACROSS TERMINALS ROOM. TEMP. 0 5.5 25º 6.4 25º 30 min. 4.2 55º 6.75 26º 60 " 4.0 60º 6.75 26º 90 " 4.0 66º 6.75 26º 120 " 4.0 68º 6.75 26º 150 " 4.0 69º 6.75 26º 180 " 4.0 69º 6.75 26º 210 " 4.0 70º 6.75 26º 240 " 4.0 75º 6.75 25º 270 " 4.1 74º 6.75 24º 300 " 4.1 74º 6.75 24º (Continued) | ||