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).
Scheme detailing modifications for the D.CD.1308 Starter Main Switch.
| Identifier | ExFiles\Box 168a\2\ img433 | |
| Date | 20th May 1939 | |
| c. Rm.{William Robotham - Chief Engineer} DA.{Bernard Day - Chassis Design}2/G.20.5.39. D.CD.1308 STARTER MAIN SWITCH. This scheme is suitable for all chassis, and incorporates the following modifications including those made in Experimental Report RM{William Robotham - Chief Engineer}/RC.{R. Childs}8/JH.11.3.39, on the switch built and tested to D.CD.692 and D.CD.1025. (1). Longer plunger having a square face in place of the conical one. This should prevent the plunger binding due to the uneven air gap caused by the cones getting out of centre. (2). Clearance between plunger and bore reduced from .025 to .005 + 4 on diameter, and support bearing deleted, as the longer plunger will provide sufficient bearing surface. (3). Switch arranged to work with plunger in the vertical position, so that weight of plunger and moving contacts will assist the off position. (4). Carbon contact made more robust and contact area increased to equal that of the copper, which is 0.41 sq.ins. (5). Solenoid winding lengthened to suit longer plunger, and iron circuit improved to maintain a more constant sectional area. (6). Moulded base considerably reduced in depth, and arranged to match a moulded cover to provide insulated cable exits, all on the one side. In view of the tests already made, this design should provide a reliable switch free from sticking and burnt contacts. DA.{Bernard Day - Chassis Design} | ||