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).
Describing the 'Utility' test procedure for spark coils and magnetos.
| Identifier | ExFiles\Box 37\1\ scan 092 | |
| Date | 7th January 1921 | |
| To R.{Sir Henry Royce} From EFC. c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to PN.{Mr Northey} c. to By.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Da.{Bernard Day - Chassis Design} c. to EWT. for R.R.Inc. X 3199 EFC2/T7.1.21. X.3199 - "UTILITY" TEST OF SPARK COIL OR MAGNETO. V.460 This was referred to in our report EFC5/T18.12.20 on bench tests of Watford magnetos. "Utility" test is the name given to a test to find out the capability of a spark generator of producing a spark under adverse, e.g. leaky, sparking plug conditions. The Ideal artificial leak would be one of pure resistance only, but it is not easily possible to obtain such a resistance which can be suitably varied. An alternative is to connect the secondaries of ignition coils or magneto armatures across one of the test spark gaps and to vary a low resistance connected to the primary circuit of such coils or magneto armatures. In the "utility" tests being made by us on magnetos and battery ignition we make use of two Remy 12 cyl. 6 volt ignition coils, these coils having the advantage that the primaries and secondaries are entirely distinct, there being not even a condenser connection between. Our "utility" test consists in (a) First trying the spark length obtainable on one of the six spark gaps fed from the distributor of the magneto or battery ignition. (b) Secondly, connecting the two secondaries of the two Remy 12 cyl. 6 volt ignition coils in series across this gap and short circuiting one primary. Note:- The effect of the two secondaries in series without one primary short circuited is practically Contd. | ||