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).
Screening for wireless interference on cars, specifically ignition resistance and dynamo chokes.
| Identifier | ExFiles\Box 163\2\ img016 | |
| Date | 18th November 1932 | |
| X 86008 PN.{Mr Northey} From Hs{Lord Ernest Hives - Chair}/Wst. & E.P. Hs{Lord Ernest Hives - Chair}/Wst.3/MA.18.11.32. SCREENING FOR WIRELESS ON CARS. Answering your PN.{Mr Northey}1/WT.17.11.32, and GN.5/WT. 17.11.32. The ignition on our cars would probably work quite well with the addition of 50,000 ohms. resistance, but immediately any leakage effects become apparent such as carboning of plugs, or moisture as when starting up from cold in the Winter time, misfires would most probably occur due to the lack of spark energy available at the plug points. We are arranging to carry out a test with 50,000 ohms resistance in order to determine the amount of available voltage for a given leak at the plug points. With reference to your memo re. 25,000 ohms carbon resistance we should imagine that the effect of inductance would also be helpful in providing a choke to the passage of high frequency currents. With regard to the note about dynamos we do consider it necessary to place a choke in series with one of the dynamo leads and a condenser across the bushes. Providing the choke has a very low ohmic resistance the effect would be negligible on the dynamo performance. We will arrange to let you know particulars of the results of our tests if possible by Monday morning. Hs{Lord Ernest Hives - Chair}/Wst. | ||