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).
The heating tests of a Rotax dynamo, comparing its performance against Smith and Lucas models.
| Identifier | WestWitteringFiles\F\April1921\ Scan59 | |
| Date | 10th April 1931 | |
| To R.{Sir Henry Royce} A.{Mr Adams} R.{Sir Henry Royce} from [REDACTED] c. to GJ. & PN.{Mr Northey} c. to Bm. & By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} & EP.{G. Eric Platford - Chief Quality Engineer} c. to HMI. for R.R.Inc. ORIGINAL EFC4/T1.4.21 X.1005 - ROTAX DYNAMO - HEATING TESTS. X.3936 The result of the heating test of the Rotax dynamo with the control brush in the position corresponding to a scan of 118 electrical degrees, which span corresponds to a curve of performance most nearly like our specified performance (as referred to in our EFC3/T17.3.21 with attached curve), the output being maintained as long as possible at 9 amperes at 14.6 volts, was as follows :- After three hours running the carcase had risen from 15°C to 98°C, the temperature of field winding resistance had risen from 15°C to 130°C and the speed from 560 to 970 r.p.m. Corresponding figures for Smith dynamo tested in the same way with brushes at maker's setting were 68°C and 94°C for the two final temperatures respectively, and 1030 r.p.m. for the final speed, and for the Lucas dynamo were 68° and 117° for the final temperatures and 1370 for the final speed. Further, towards the end of the test the heating was such that 9 amperes was the peak output and for the last 20 minutes it was not possible to maintain the output above about 8 1/2 amperes. Thus, as anticipated, from the point of view of heating the Rotax dynamo is hardly capable of the performance we require and can therefore not really be considered suitable for the R.R. car. The speed it will be noted is considerably Contd.. | ||