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).
Wiring and improvements of an auto switch unit.
| Identifier | WestWitteringFiles\R\2December1927-February1928\ Scan157 | |
| Date | 9th February 1928 | |
| In this combined unit we have, in accordance with previous explanations, shown both shunt coils supplied with positive current from distribution box terminal C which normally supplies the field current. We think this is the right way. It results in the auto switch having three terminals only. We are also sending you an up-to-date diagram of a single auto switch unit giving the terminals and winding directions approved for this case of such a unit which is directly applicable to existing cars. In this case we have four terminals because the cutout shunt coil is supplied from the distribution box terminal B, and for a reason previously given, the auto switch shunt coil should also be supplied from this same terminal B, the field current, however, must be supplied from terminal C and there must therefore be four terminals. Since fitting the auto switch unit to your 14-EX car we have arrived at and made some minor improvements. For instance, we found it much better to let the contact points meet normally, as there might be a slight tendency to tax inconsistent working with the contact points meeting not normally as in the unit which you have. With these minor improvements we have now got equally consistent working with these new units as we originally obtained with those which we knocked up out of distribution board parts. We understand that the necessary steps have been Contd. | ||