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).
Dynamo switch configurations, circulating current, and output variations on different machines.
| Identifier | WestWitteringFiles\G\October1921\ Scan8 | |
| Date | 7th October 1921 | |
| R.R. 235A (100 T) (S.H. 798, 10-12-20) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2947 Contd. -2- EFCS/T7.10.21. conductors leading from the dynamo to the switchbox and a four-point dynamo switch to take the connections between Field, control and negative terminals and one line wire simultaneously. It was considered it might be possible to keep the control and negative brush connected together so that the three-point switch would serve the purpose. This might have been done on the E.575 machine as the control circuit current and the sparking at the control and negative brushes were no more than normal, and no harm would be done, but in the case of this machine we find by trial that the circulating current is altogether of too large a magnitude, and the four-point switch would be absolutely necessary if this dynamo is used. As already reported, Messrs. Lucas are submitting to us a second machine made up on the single field winding third brush control scheme, and they state that they consider they will be able to obtain the same output characteristics with this other machine. We think that the argument of the variation of output due to the variation of the control brush bedding exists to almost the same extent on the standard Lucas system as it does in the more simple system. We have certainly found variations in the output curves due to this cause. In any case, we do not think the variations with the simple system are serious. It is therefore to be hoped that this other machine will put up an equal performance, as it will no doubt be of the same quality and finish and would appear to be a good Contd. | ||