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 results for two sets of screened ignition cables fitted with different Lodge screening caps for tank engines.
| Identifier | ExFiles\Box 163\2\ img066 | |
| Date | 3rd August 1933 | |
| 6008 E.{Mr Elliott - Chief Engineer} From Ha/Wst. c. to Wor.{Arthur Wormald - General Works Manager} c. to By c. to Mx.{John H Maddocks - Chief Proving Officer} c. to F.{Mr Friese} c. to RHC{R. H. Coverley - Production Engineer}/CEP. Hs{Lord Ernest Hives - Chair}/Wst.8/MA.3.8.33. IGNITION SCREENING FOR TANK ENGINES CONTRACT T/555. We have now tested two sets of screened ignition cables fitted with two different types of Lodge screening caps. One set of cables were fitted with the combined plug and screen known as type SR and the other set fitted with the type L screening cap designed to fit an ordinary sparking plug. The voltage necessary to spark over the plug points with the plugs under pressure at 100 lbs per sq.in. was measured with and without the screening and the following results were obtained :- TYPE. OPERATING VOLTAGE % DIFFERENCE. WITH SCREEN. WITHOUT SCREEN. L 5900 5020 14.7 Increase with screening. SR 5500 4840 12.0 Increase with screening. This difference of potential should still be well within the capabilities of our ignition system. We are now handing these cables and plugs over to Mx.{John H Maddocks - Chief Proving Officer} in order that they may be engine tested. Will Mx.{John H Maddocks - Chief Proving Officer} please arrange to return these wires to us at the completion of his tests. Ha/Wst. | ||