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 effects of an auto switch and cutout on a dynamo's field circuit and charging current.
| Identifier | ExFiles\Box 59\1\ Scan337 | |
| Date | 27th October 1927 | |
| -5- Contd. We also wrote a sister report EFC7/T27.10.27 in which we considered similar things for the auto switch. We pointed out that the effects already mentioned of operating the auto switch before the cutout were independent of the magnitude of resistance inserted in the field circuit, unless R was so large that the dynamo could not maintain the cutout on contact, in which case a low frequency full travel vibration might take place, i.e. with the negative end shunt coil as originally connected. We reported that we had found that if the resistance thrown into series with the field was more than the amount to reduce the charging current approx. 60%, the auto switch, if non-flexible, might act as a vibrator regulator and within a certain range of slightly varying dynamo speed; this phenomenon being one of normal running was independent of the method of connection, but very dependent upon the R, and would take place upon the road if R was too large. both types of fault Further, it was pointed out that (1) and (2) were entirely overcome by changing the negative end of the shunt coil to the battery side of the cutout. It was noted that this change put us less well off as regards the protection against breaks in the dynamo-battery circuit, because it did not include the cutout operation. It was observed that the further problem was that of getting a big reduction of the charging current without the auto switch becoming a vibrator regulator. It was also observed that if some means had been found which enabled us to increase the value of R without | ||