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).
Changes to the insulation of ignition coils for 20-HP & 40/50 HP chassis.
| Identifier | ExFiles\Box 69\1\ scan0283 | |
| Date | 31th December 1929 | |
| RHC.{R. H. Coverley - Production Engineer} EFC. X 8710 BY/RD1/DM.{D. Munro}31.12.29. Ignition Coils. 20-HP. & 40/50 HP. Chassis. Would you please arrange to let EFC. have 2 Ignition Coils which are standard in all respects, except that the secondary insulation consists of 2 turns per layer instead of 3 turns per layer of waxed or varnished paper. The first 3 layers of secondary will be insulated with 4 turns of insulating material instead of oiled silk as at present. This new coil should be marked with the piece number D.72450. The object of this is that we get a more solid winding together with an economy in wire and insulating paper, in fact the less paper we use the less amount of air is trapped therein. Will EFC. please test these 2 coils, one of which should be wound with varnished paper and one with waxed paper, and as soon as possible, as we propose to adopt this on production forthwith. BY/RD. | ||