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 ignition system's coil, condenser, and contact breaker, comparing Bosch and American components.
| Identifier | ExFiles\Box 61b\4\ scan0051 | |
| Date | 18th July 1921 guessed | |
| Oyl - G 18721 Sheet #3. As regards the protection of the coil, the only H.T. terminal is of a similar type to the magneto H.T. terminal and could be turned, as shown above with the open side away from the fan blast. The standard position for the Bosch coil is on the dashboard, and perhaps it would be worth while ascertaining by experiment whether this position gave us inferior ignition with the American Bosch outfit. X.2512 (4) Condenser - This is of the standard American battery ignition type. A sample of a Westinghouse condenser similarly made was sent to Mr. Royce with my letter Oy2/G25521 re "Distributor and Contact Breaker". The Westinghouse Co. use paper impregnated with "Halowax", made by the Condensite Co. This wax has a high melting point and dielectric strength. The Bosch Co. use a double thickness varnished paper, sample of which is attached. Double thickness is used for increased dielectric strength and decreased chances of faults. The two strips of double thickness paper and two strips of tinfoil are wound on an oval shuttle by hand. Each strip passes under a rubbing contact which removes dust from the strip. The winding handle is connected to a Veeder counter, and at every so many turns the operator inserts a small strip of tinfoil for making the connections. Three connections are thus made at equal distances along each plate. When the condenser is wound, it is pressed between dies to the "kidney" shape and inserted in the metal box. The wax which flowed on 4-EX was the black insulating wax on the condenser connecting strip which runs from the condenser to the L.T. terminal on the contact breaker casing. This wax is now replaced by one having a melting point of 220°F.{Mr Friese} X 1819. (5) Contact Breaker - The oil inside the contact breaker casing is due to the car having been turned over on its side during a testing run. It is engine oil from the crankchamber. The whole head was flooded, but as soon as the car was righted, the battery ignition operated perfectly. | ||