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).
Test report on the effect of an auxiliary gap in improving ignition coil sparking.
| Identifier | WestWitteringFiles\F\January1921\ Scan16 | |
| Date | 31th December 1920 | |
| 88261. EFC. 31.12.20. X.3199 - EFFECT OF AUXILIARY GAP IN IMPROVING IGNITION COIL SPARKING. To carry out this test with various main gap leakages, a variable gap was placed in series with one of the six gaps, operated from the distributor. Across this main gap a leakage was arranged with 12 cyl. 6 volt Remy ignition coils as described in connection with the "Utility" test (15.12.20). Without any leakage across the main gaps, the auxiliary gap appears to have no advantageous effect. With two Remy coil secondaries in series, with the primaries short circuited, across the main gap alone, sparking ceases completely at 5.25 mm. The introduction of an auxiliary gap also of 5.25 mm, restores sparking almost regularly. With one Remy secondary across with the primary closed, the main gap ceases fire at 2.75 mm. An auxiliary gap of about 3.0 mm. now allows fairly regular sparking to occur. With a leakage across the main gap an auxiliary gap of about .004" quite perceptibly improves sparking. Within the limits of the possibility of sparking at all, it seems that the wider the auxiliary gap, the more certain is a spark to pass at the main gap. F.J.A. | ||