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).
Experiments with a magneto generator and Weston voltmeter for electrical speed indicators.
| Identifier | ExFiles\Box 33\5\ Scan006 | |
| Date | 24th June 1915 | |
| X.1807 To Wor.{Arthur Wormald - General Works Manager} for Hy.{Tom Haldenby - Plant Engineer} from R.{Sir Henry Royce} c. to J.{Mr Johnson W.M.} c. to Wor.{Arthur Wormald - General Works Manager} for Mr. Ellis. R5/IB24.6.15. X. 2125 - RE MAGNETO GENERATOR AND WESTON VOLTMETER ELECTRICAL SPEED INDICATORS X.1782. X.1807. Will you please let Mr. Haldenby experiment with themagneto generator and Weston voltmeter electrical speed indicators. I have not seen the magneto generator, and I fear it is a heavy and clumsy apparatus, but the Weston voltmeter is an extremely neat little instrument indeed, and there are many uses for such an instrument providing we can get the necessary technical data belonging to it, as I have written to Mr. Nadin. In this particular set Mr.Haldenby, together with Mr. Ellis ought to endeavour to find out the voltage and current necessary for the various indications, and whether the indications truly represent the speed at which the magneto is driven; that is to say, whether the equal grading on the scale of the voltmeter represents exactly the speeds intended. This would depend, to some extent, on the magneto generator. For instance, it is supposed that the magneto gives volts directly in proportion to its speed, and the voltmeter is graduated assuming this to be so, but if the magneto generates much current, or has an armature which is not correctly laminated and therefore not free from eddy currents, the reaction of the armature of the generator will cause the field magnets to weaken, and therefore the high reading would read low on the voltmeter. | ||