Rolls-Royce Archives
         « Prev  Box Series  Next »        

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).
Comparison of the performance curves for Lucas, Smith, and Rotax dynamos.

Identifier  ExFiles\Box 36\4\  scan 171
Date  17th November 1920
  
Contd. -3- EFC1/T17.11.20.

performances of the Lucas and Smith machines controlled in their respective manners and for this purpose we have drawn curves of these other performances on the same sheet on which the performance of the Rotax is shown hot and cold. We have also drawn on this sheet our specified performance for any dynamo for the R.R. car. Regarding the performances of Smith and Lucas dynamos shown, these are the averages of three independent experimental curves, but it should be stated that in the case of the Lucas these were taken on dynamos with the control brush in the makers' original position and not in the somewhat retarded position in which we now receive them with the object of reducing the singing of the machine to a more reasonable amount.

The output of the Rotax machine will be seen to rise to a maximum very rapidly and then fall considerably. If the curve found for cold performance represented the performance hot, we should say that this was quite a desirable form of output curve, but we think it will be agreed that, taken all round, the output of the Smith 2D is, for an inherently controlled machine, the best that we know by a considerable amount.

Curves of the field currents of the Rotax dynamo are given, showing how this current drops away as the speed increases. The Rotax dynamo may have a slight advantage as regards efficiency owing to the not having excited coils in opposition and to the fact that the field current results

Contd.
  
  


Copyright Sustain 2025, All Rights Reserved.    whatever is rightly done, however humble, is noble
An unhandled error has occurred. Reload 🗙