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).
Spark characteristics, oscillation, and the effects of varying secondary gap.
| Identifier | ExFiles\Box 52\3\ Scan292 | |
| Date | 6th August 1919 | |
| H.R. 235 A (100 T) (S.F. 846 6-8-19) G 2460 Contd. -4- EFC {E. Fowler Clarke - Electrical Engineer} 2/T111217. All sparks resume on dropping speed to 1100 R.P.M. It may be mathematically proved and is pointed out in accompanying notes that after the instant of secondary spark, the primary current consists of an oscillation of higher frequency and greater damping than in the absence of the secondary circuit, the amounts of these quantities depending upon the closeness of the coupling between primary and secondary. The closer the coupling the more rapid and more quickly damped are the oscillations. If the speed is not too low and the coupling not too good, and make follows break after a short enough interval, there might still be some oscillation going on at make, which would fizzle out at make, by the condenser discharging itself across the gap, and causing a "splashy" spark, as observed for Remy 6 at highe speeds. One would think that a spark of this type was much less injurious to the contacts than the soft arcy variety. ----- Effect of variation of secondary gap. Remy 1.2. Speed 900 R.P.M. Primary gaps .020". We found that reduction of secondary gap length from maximum possible length to indefinitely small gaps | ||