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).
Tests conducted on ignition coil insulating papers for secondary winding insulation.
| Identifier | ExFiles\Box 61\1\ scan0137 | |
| Date | 15th October 1930 | |
| X6110 By.{R.W. Bailey - Chief Engineer} from EFC. c. Sft{Mr Swift}/Mr.Brock EFC2/AM15.10.30. X 6110. X.1109. X 8712. IGNITION COIL INSULATING PAPERS FOR SECONDARY WINDING INSULATION. Further to our EFC4/AD10.10.30, further tests have been carried out on three other samples of insulating paper handed to us by Mr.Brock namely, Symon's varnished paper, Symon's untreated glazed paper, Symon's untreated plain white paper baked and wax impregnated. The tests carried out were similar to those reported in our note above referred to, and my assistant's report WE.53 on the actual tests reads as follows, the figures given being definitely comparative with the similar figures given in the previous report :- "The peak breakdown voltage test on a .0045" thickness of each sample gave the following results :- Peak breakdown volts per mil. Varnished paper - 7940 volts - 1764 Untreated glazed paper. - 4080 volts - 907 Plain paper wax impregnated. - 6350 volts - 1410 The conductance test on each sample gave the following results. Paper tested. | Conductance at 60°C. | Conductance at 80°C. | Conductance at 100°C. Varnished | 0 | .0004 mms | .001 mms Plain glazed. | 0 | 0 | 0 Plain wax impregnated. | .002 mms | .008 mms | .038 mms mms. = micromhos. | ||