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 shunt wound machines, including Bosch, Smith, and Bijur, focusing on performance and output curves.
| Identifier | WestWitteringFiles\E\July1920\ Scan27 | |
| Date | 22th July 1920 | |
| Contd. -3- EFC1/T22.7.20. simple shunt wound machines, or may be used as simple shunt wound machines, making use of the full available winding space for a field winding (which condition excludes the Lucas machines owing to their control windings), the Smith machines come next to the Bosch in this respect and later on comes the Bijur 12 volt machine. The matter of open circuit voltage is, however, of course, not the only consideration, it being necessary to study at the same time the ampere output speed curve of each machine when operating on an ideal battery with scheduled volt-ampere characteristic. X2608 Our curves show that the Bosch ampere output speed curve, in spite of its early voltage, does not bend over and cross the others; in other words, the performance of the Bosch as a shunt wound machine is definitely considerably better than any other. It was so much better that it has been necessary to have a specially large pulley for driving this Bosch machine, owing to the high torque necessary to correspond to the low speed for a given power; otherwise we were troubled with slipping of the belt. Between the Smith and the Bijur machines there is not very much to choose. The Smith machines (used as shunt) are a little earlier in cutting in, but the ampere output speed curve does not rise so quickly, and therefore, in general, crosses the curve for the Bijur machine in a way which will be illustrated when our curves are issued. It would appear that in designing our own Contd. | ||