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).
Specifications for two experimental ignition coils with tapped secondary windings for voltage measurement.
| Identifier | ExFiles\Box 69\1\ scan0323 | |
| Date | 7th May 1930 | |
| Memo from EFC. c. Sft{Mr Swift}/Mr.Brock. c. Ry. X8710 EFC5/AM 7.5.30. X.8710. IGNITION COIL WITH TAPPED SECONDARY WINDING FOR LAYER VOLTAGE MEASUREMENT. X6014. Our preliminary experiments with the ignition coil with tapped secondary which we asked you to obtain for us in our EFC2/AM1.2.30 have shown up some interesting results regarding the distribution of peak voltage in the layers. It now becomes desirable to try another otherwise standard coil in which the inside end of the secondary is not connected to the outside end of the primary but is independently brought out so that we may connect it as desired, the coil also to have the following tappings :- One after the second secondary layer, one after the 4th secondary layer, one after the 6th secondary layer, one after the 24th secondary layer, one after the 26th secondary layer, and in order to compare the voltage in the top layers one after the 54th layer one after the 56th, the last one or H.T. end of the secondary being the end of the 58th layer. A second coil, exactly similar to the above with similar tappings with the exception that the lower layers are provided with tinfoil inter-leaving in a similar way to that described verbally to Mr.Brock, who produced for us an experimental ignition coil with tinfoil so arranged therein which coil has so far behaved very well. We shall then be able to compare the layer P.D's and whether the potential gradient across the inner layers where breakdowns have occured is or is not stabilised as the case may be. EFC. | ||