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).
Explaining the methodology for creating and interpreting utility performance curves for magnetos.
| Identifier | ExFiles\Box 48\2\ Scan300 | |
| Date | 9th July 1925 | |
| UTILITY PERFORMANCE CURVES OF MAGNETOS. These curves are drawn on a horizontal base of angular position of primary break with a vertical scale of speed in r.p.m. The datum for the angular position of break is the position 0° at which maximum flux is induced through the armature under stationary conditions. The vertical reference line is drawn to correspond to a position of 90° later than this. The contact breaker range of the magneto is roughly 60°, i.e. from 90° approx. full advance to 150° approx. at full retard. The vertical lines drawn of the limits of contact breaker range enclose, together with the high speed and low speed curves, an area at every point inside which the magneto, in the condition represented by that point, is capable of firing the standard leaky gap, defined in par.(5) of our General Specification of Magneto Performance. Thus the utility performance of various magnetos may be graphically compared by plotting such diagrams. In the present case this has been done for the present standard magneto No. 77606, and also for a special magneto No. 82558. Contd. | ||