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).
The experimental testing and failure analysis of various ignition coils.
| Identifier | ExFiles\Box 69\1\ scan0257 | |
| Date | 15th November 1929 | |
| X.8710 15.11.29. X.8710 X.4501 EXPERIMENTAL IGNITION COILS. Standard type, but with paraffin wax paper in place of varnished paper. We have had three of these. One has failed in normal experimental operation. L.S. type. Primary winding with no extra insulation at ends paraffin wax paper secondary insulation and 20,000 secondary turns. We have had seven of these. One (L.S.8) has failed on prolonged excess voltage test. Five others O.K. on cars, and one O.K. on bench. L.C. type. Larger core, larger gauge primary winding without extra insulation (21 SWG. in place of 22 SWG) thick paxolin tube slipped over primary to form rigid base for secondary. 19,000 turns of secondary with standard varnish paper insulation. We have had four of these. Two (L.C.2 & L.C.3) broke down on preliminary schedule tests and were unwound for inspection and no obvious fault was found in either case. The other two (L.C.1 & L.C.4) are going O.K. on experimental chassis. | ||