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).
Comparison of the performance, overheating, and design characteristics of various dynamos, including Westinghouse, Bosch, and Rotax models.
| Identifier | WestWitteringFiles\F\January1921\ Scan20 | |
| Date | 30th December 1920 guessed | |
| Contd. -3- EFC3/T11.1.21. in the speed curves and applies only to Westinghouse, Smith 2D, Bijur and Bosch, but it was only the Westinghouse, Bijur and Bosch that were able to attain a nearly steady condition at this larger output without excessive over-heating. Figures for the final conditions attained are given on the accompanying table to which we have also added the various weights of the machine for comparison. Whereas the open circuit volt-speed and the ampere-speed curves of Bosch and Rotax are approximately the same, the Rotax is really a smaller and much less massive machine and heated up unduly when made to give the 9 amperes at 14.6 volts. It should be noted, however, that the Rotax and the U.S.A. Bosch dynamos were really third brush controlled machines with a lower resistance field winding than would be normal, but for the purpose of comparison of performance and arriving at the limitations of the lowness of field winding resistance, it was considered it would be useful to compare these as shunt wound machines with the other dynamos. The Westinghouse machine, which is late on all the volt and ampere curves, is naturally a very cool running machine at a given output. The Bosch machine which is early on all the curves is alright on the small output, but gets rather hot on the large output. This machine, of course, is considerably more massive than the others. Contd. | ||