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).
Test report on dynamo voltage output and contact sparking, leading to a compromise using a resistance to simulate a load.
| Identifier | ExFiles\Box 59\1\ Scan150 | |
| Date | 29th June 1920 | |
| Customer's No. 2. temperature. It was found that at 3000 rpm (about 41 car mph) on open circuit, the machine put up 16.0 volts and above that speed could rise to much higher values. At this value of resistance however, considerable contact sparking was beginning to appear when introducing it into the field circuit. It was therefore decided to effect the compromise of using a resistance of such value that the dynamo would light a tail-lamp (roughly representing an ignition load) at 16.0 volts at 3000 rpm. The value required to do this was found to be 165 w., but this was low enough to render the contact sparking reasonably mild. The length of 22 SWG Eureka wire was 18.5 ft (cont-d) | ||