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).
Difficulties and potential solutions for isolating starter motor circuits on Phantom II and 20/25 models.
| Identifier | ExFiles\Box 166\3\ img007 | |
| Date | 1st December 1932 | |
| Ry/RD. from Hs{Lord Ernest Hives - Chair}/Wst. c. E.{Mr Elliott - Chief Engineer} c. CX.{Major Len W. Cox - Advertising Manager} X6090 Hs{Lord Ernest Hives - Chair}/Wst.2/ADB.12.32. RE : ISOLATION OF STARTER MOTOR CIRCUITS P.II and 20/25. With regard to Sale's request for the starter operating relay circuits to be off when the switchbox is off as per your Ry/RD2/W7.12.32. We cannot agree to the scheme as outlined on the blue print sent us owing to :- (a) The starter main switch and teazer current being fed through the ammeter. (b) The starter relay circuits being unprotected by a fuse other than the heavy main emergency fuse. In the case of the 20/25 where no teazer circuit is incorporated, there would be the main switch operating current which, with the switch proposed, would amount to 14 amperes at 12 volts. With the lamps and ignition switched on this sends the ammeter needle off the scale and would be alarming to some customers. In the case of the 40/50, the main switch plus teazer current at 12 volts amounts to 32.5 amperes which, with lamps and ignition on, would damage the ammeter upon repeated use. The only possible way of successfully isolating the starter circuits is by means of a separate switch taken from terminal 8 on the distribution board. Even this, on the 20/25, would not give adequate fusing protection for the starter relay circuit as no accessory box complete with fuses is fitted. We pointed out in our Hs{Lord Ernest Hives - Chair}/Wst.5/ADL9.1.32 and Hs{Lord Ernest Hives - Chair}/Wst.1/9.2.32 what we considered to be the best schemes and we understand you have a switchbox designed on these lines similar to the Bosch which will get over our difficulty entirely. For the existing 20/25 and P.II we can see no way out of the difficulty other than the use of a separate master switch. Hs{Lord Ernest Hives - Chair}/Wst. | ||