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).
The failure of a carbon copper type starter switch due to incomplete pedal depression.
| Identifier | Morton\M1.1\ img060 | |
| Date | 15th September 1921 | |
| E.{Mr Elliott - Chief Engineer} from Hs.{Lord Ernest Hives - Chair} Ref Hs{Lord Ernest Hives - Chair}1/Lg 15-9-21 ORIGINAL H82/LG4.10.21. X505 X3757 CARBON COPPER TYPE STARTER SWITCH. The carbon copper starter switch which has failed when in use by us has been the one fitted to 5.EX Car which has a 3-speed box and starter on the flywheel. The failure occurred due to the pedal not being pressed completely down. The blade carrying the copper contact became red-hot and took a permanent set. The contact between the carbon brush and the blade is very poor - it is at that point the heating commences. We are sending the blade to you. We consider that the carbon copper contact switches are only satisfactory when operated by relay. We feel it is bound to happen that the switch will not be completely closed when it is hand or foot operated. This is very likely to happen with the carbon contact switch because it must necessarily have a longer range of movement. As soon as the carbon contact is made, the motor will dash off and the operator might easily then stop pressing the starter pedal any further. Failures of carbon copper switches may be attributed to abuse but they are certain to get abuse on a car. All the American cars we have handled have had plain starter switches and we have never had any trouble with them. Lucas' are using a switch very similar to the Delco. We shall be using this switch on Coshawk 11. until the R.R. is ready. EFC. is in agreement that a plain switch similar to the Marmon should be more reliable than one with carbon and copper contacts when operated by foot. Hs.{Lord Ernest Hives - Chair} Hs{Lord Ernest Hives - Chair} supplies the evidence asked for. Hs.{Lord Ernest Hives - Chair} | ||