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).
Specifications for a Weston R.P.M. Indicator, instrument model 269, No. 336.
| Identifier | ExFiles\Box 33\4\ Scan225 | |
| Date | 22th October 1925 | |
| X1782 22.10.25. X.1782 - WESTON R.P.M. INDICATOR. X.1807 INSTRUMENT MODEL 269 . No. 336 Millivolts for full scale deflection 57.45 Milliamperes for full scale deflection 10.95 Hence resistance of instrument = 5.25 ohms. Scale proportionally very fair. Hence error within ± 1%. EFC. | ||