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 bench testing and performance analysis of a dynamo, including its physical specifications.
| Identifier | WestWitteringFiles\G\September1921\ Scan94 | |
| Date | 30th September 1921 | |
| R.R. 285A (100 T) (S.H. 798, 10-12-20) G 2947 Contd. -3- EFC1/T30.9.21. provided to effect the connection of four points at the same time. The dynamo looks quite a nice job and has a dull nickel plated finish. On the bench tests we have carried out it has run consistently well. There has been a slight evidence of magnetic hum, but we do not think this will cause us any trouble on the chassis. There is only one brush per brush holder in place of two on the E.575. This has been done to reduce the vibration of the brush holders. The attached photostat gives curves of output in both cold and fully hot conditions with the operating voltages. In the cold condition the output curve, after passing the peak, is somewhat variable depending on the exact bedding of the control brush. In the fully hot condition it is much more stable. It will be noticed that the output curve readily meets our specification of output and has a remarkably rapid rise of output after the cutting-in point, hence, as regards electrical performance, the machine is very good. In the cold condition a cutting-in voltage of 12.4 is attained at a speed of 485 r.p.m. In the fully hot condition a cutting-in voltage of 13.6 is attained at a speed of 565 r.p.m. The carcase diameter is 5". The weight of dynamo, inclusive of pulley, but exclusive of suspension 8ags is 24 lbs. - our suggested limit being 25 lbs. The armature dia. is 3.125", active length 3.30", carcase length 5.55". | ||