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).
Use of paraffin wax for insulating ignition coils.
| Identifier | ExFiles\Box 69\1\ scan0154 | |
| Date | 11th October 1928 | |
| To BY.{R.W. Bailey - Chief Engineer} from EFC. c. BY/RD. c. Mr. Brock. X8710 EFC9/T1.10.28. PARAFFIN WAXED PAPER INSULATED AND PARAFFIN WAX FILLED IGNITION COILS. We have not been able to prove any material advantage of the paraffin wax insulated coils (secondaries) over the standard, but we think there is a slight advantage because we have definitely shown that the leakage of the paraffin waxed paper under D.C. pressure is less than that of the present standard oiled paper. Further experiments, however, are in progress. We think it may be an advantage to increase the margin of voltage of the coil in any case by making use of 20,000 turn secondaries, and we have informed you elsewhere to this effect, and asked you to instruct coils accordingly. In regard to paraffin wax filled coils, please find attached copy of my assistant's report WD.{Mr Wood/Mr Whitehead}14 which I think you will find instructive. Pure paraffin wax not taken above 130°C. is absolutely leakless on our test at the highest pressure and degree of current sensitivity which we utilise, but, as referred to, in the report, soon becomes conductive if taken much above, say 150°C. owing to the cracking which takes place. As concluded in the report, we do not think there is going to be much advantage of coils filled with paraffin wax over coils made up with paraffin waxed paper which we think should be right when the arrangements of the coil and the circuit is right in other respects. EFC. Attached WD.{Mr Wood/Mr Whitehead}14. | ||