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).
Electrical resistance and power distribution in an actuating magneto coil to reduce error in a Lucas switch.
| Identifier | WestWitteringFiles\D\March1920\ Scan18 | |
| Date | 1st March 1920 | |
| To CK.{Mr Clark} from R.{Sir Henry Royce} -2- R5/G12/3/20 Contd. susceptible to temperature changes. I suggest that 5 volts be absorbed in the actuating magneto coil and 10 volts in the external resistance coil. if we used .300 current to operate it, it should be the maximum. we should then, in the R.R. proposal, get only 1 1/2 watts in the actuating coil and 3 watts in the resistance coil. The total resistance of the fine wire circuit would be about 50, 17 being on the magnetic, and 34 on the external resistance. The external resistance can be quite a small unit (so long as it does not get hot enough to roast the insulation) as the wire having a very low temperature coefficiency would not matter if it did get hot. By such a policy I believe we could alter the fault shewn in your tests of the Lucas switch by about four, that is, it would be only 25% of its present amount of error. R.{Sir Henry Royce} | ||