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).
Letter from Bosch Limited answering technical queries about a dynamo's performance and load.
| Identifier | ExFiles\Box 60\4\ Scan130 | |
| Date | 22th December 1931 | |
| Page -2- BOSCH, LIMITED Date December 22nd, 1931. (a) What is the maximum open-circuit speed at which this dynamo can be run without undue heating on the regulator points occurring - The limiting factor under these conditions would be the reliability of the ball races. We consider that you can speed this dynamo up to 5,500 r.p.m. for periods of 15 minutes with perfect safety. With regard to your question (b) Is it possible to satisfactorily run this dynamo under any conditions, i.e. with lamp loads or just ignition load, without being connected to the battery It would be practical to run this dynamo under these conditions for several hours without any ill-effects. We note that your complete lamp load was approximately 120 watts and the battery capacity 80 amp. hours, 12 volt. We would advise you the dynamo was regulated for a lamp and ignition load of about 200 watts, in accordance with your Order No. 16304 dated 23rd June. If you only have a 120-watt lamp load and say approximately 20 watts for the ignition, we should s e t the regulator a little lower. Please be informed, however, that this has nothing at all to do with the trouble which has been experienced, namely the burning of the contacts. We are returning this dynamo to Stuttgart, and sending them a copy of this letter, and we await your reply, so that we may pass same on to them to help them in their investigation. Thanking you for your co-operation in this matter, we are, Yours truly, BOSCH LIMITED, [Signature] Technical Manager E7711. H.J.G. 5M-4.31. | ||