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).
The issues of screening a speedometer and revcounter from interference generated by an ammeter and petrol gauge.
| Identifier | ExFiles\Box 59\2\ Scan382 | |
| Date | 12th January 1934 guessed | |
| Screening of Speedometer and revcounter from ammeter and Petrol Gauge 86051 This screening cannot be carried out successfully on the speedo or revcounter as a slight oscillation is still obtained on the ammeter and petrol gauge. The screening of the speedo or revcounter has a great disadvantage, the screening which must be of iron interferes with the working of the instrument, and has an effect of making the instrument from 25 to 33% slow on its normal calibration. It is doubtful if this error can be compensated by the magnetic shunt fitted for this purpose. The most effective way of screening is by screening the ammeter and petrol gauge. This means that the instrument must be screened all round the side and back and the dial must be of iron. There is a strong magnetic field of an oscillative character radiated from the center of the instruments, and | ||