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 performance, focusing on series winding, commutator sparking, and potential improvements.
| Identifier | ExFiles\Box 179b\1\ img354 | |
| Date | 14th March 1933 | |
| HS{Lord Ernest Hives - Chair} Received FROM R.{Sir Henry Royce} ORIGINAL VIBRATOR CONTROL. R5/W10.3.33. Sent off 14.3.33. x6092 I am pleased to hear that you are making some progress as regards vibrator control and dynamo. In one of your memos. you mention trying some series winding on the dynamo. I cannot see how this can do any good, either arranged to help the winding, or to oppose the winding. It would merely mean that the shunt winding was cut out more or less to make up for the series winding. I could imagine however that some series winding on the vibrator control would help its magnetism, and prevent excessive rush of current in case the battery is down, but I do not think this will be touching the point that is worrying - "the sparking at the commutator". In my own experience which was very extensive in dynamos in the pioneer stages the best improvements were increased number of sections in the commutator, and a decreased polar embrace of the pole pieces, and a field system that had small distortion, leaving a rather larger period for peaceful commutation. In the very early days we made a good reputation upon this feature of sparkless commutation. In passing one might suggest that it would be a good thing to see whether the wear of the brushes was very much different running on a commutator without any current, and also whether it was affected very much by temperature of the commutator. If we can reduce the sparking we can probably reduce the heat of the commutator and so get a combined advantage. My own feeling is that it must of necessity very largely benefit the dynamo if the revs. were not so high. Higher speed must make more heat, friction, sparking, wear, and everything, and if our tests shew to the contrary then something has deceived you, and the experiment should be repeated until we are sure we are not being deceived. If the vibrator is satisfactory then we can, and must, have this system quickly. For a given useful output it is easier on the dynamo than the miserable 3rd. brush and its conditions. R.{Sir Henry Royce} WST See me HS{Lord Ernest Hives - Chair} | ||