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).
Description of a pole-shoe arrangement and distributor gear wheel for an electrical ignition component.
| Identifier | WestWitteringFiles\F\January1921\ Scan45 | |
| Date | 28th January 1921 guessed | |
| P.A.38. -2- Contd. the main body of the shoe. Encircling the section where the extension widens out into the main shoe, is fixed a thick rectangular band or collar. This arrangement at low speeds would act simply as an extended pole-shoe which would allow the flux to be dragged forward, and thus give a better spark at retard. As the speed rose, the induced current set up in the low resistance band, would create an M.M.F. opposing and tending to choke back the main flux attempting to pass it, so that at high speeds, this part would automatically be virtually cut off and only the two main parts of the shoes would be in action. Oilways are provided, one to each bearing. The distributor gear wheel, is made of brass and has riveted to it a narrow aluminium ring which it is claimed acts as a damper, reducing the noise of the gears. C.A.P. | ||