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).
Material comparison report testing the voltage breakdown and punchability of different bakelite and paper samples.
| Identifier | ExFiles\Box 39\3\ Scan311 | |
| Date | 1st December 1924 | |
| RR 238 (150 BKS.) (OB 451-8 12-24) MP 306975 ROLLS-ROYCE LTD. INSTRUCTIONS. To _________ Order No. ________ Customer's No. 5 | Material | R.M.S. Volts | Peak Volts per mil | | :--- | :--- | :--- | | Cont. bakelite .035" | 9700 | 392 | | " " .065" | 9000 | 196 | | " .065" | 16200 | 352 | | Bakelaque cloth .072" | 10800 | 477 | | " paper .020" | 6150 | 435 | From this it appears that the Bakelaque is superior to our present standard, although breakdown strength is not of first importance for our purposes. The samples of Bakelaque have had some washers punched from them. The cloth variety punched fairly well, but not quite so cleanly as the standard, while the paper grade was slightly more ragged at the edges. Signed (WACE) This Sheet must be filed on completion of the work. | ||