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).
Typed memorandum discussing design specifications for an electromagnetic component.
| Identifier | ExFiles\Box 64\3\ scan0003 | |
| Date | 1st January 1924 | |
| -2- R3/M1.1.24. We have arranged convenient copper strips and connections and this rish should ensure the magnet acting against a good pull off spring which is necessary for establishing a good contact for the current going to the actuating magnet. After the armature has been pulled down a small current will hold it down but the gauge of wire for this secondary winding I do not know. Make it fine enough to not roast in any time it is likely to be on, and coarse enough to ensure the magnet holding its armature against the spring mentioned earlier; perhaps about 10 ohms would be about right. There should be no mistake about this scheme being about right straight away, but some good judgment will be required to criticise and modify it quickly, but I have indicated the object and the limitations fairly clearly. There is only the one non-inductive resistance mentioned that I can see any need or advantage to have. Mr. Clark will look into this matter. R.{Sir Henry Royce} | ||