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).
Proposed design variations for a distribution box and its electrical connections.
| Identifier | WestWitteringFiles\R\2October1927-November-1927\ 185 | |
| Date | 21th November 1927 guessed | |
| -3- Contd. to the cutout, the external connections to this box being precisely as at present. We feel confident enough of the results to ask for a design of such a distribution box. In the diagram there are two slight variations from the exact electrical arrangement which we are testing, for reasons which we have already given and now repeat - (1) The negative end of the auto switch shunt coil is taken not to earth but to the moving contact or lever of the cutout, the object being to include in the protection given by the auto switch faults in the series coil and the earthing connection of the series coil of that unit. (2) The positive ends of the shunt coils of both the auto switch and the cutout are together connected to the C terminal of the distribution box and fed through the field fuse instead of as arranged for the standard system being both connected to the B terminal. From the point of view of electrical functioning there is, as we have indicated, very little in this change. It means, however, that there are only three connections to the auto switch unit instead of four, a circumstance which might facilitate removal of that unit. With the auto switch on the system and in working order, the field fuse is unnecessary from the point of view of protection of the dynamo and the system, and in any case such present protection is only partial. It still remains of the same kind of use as the armature fuse is at present, viz. as a protection against earths on the dynamo wires if the charging switch should be "on" and the engine stopped. It would probably be desirable to retain it in case the auto switch were removed or out of action for any reason, leaving the system only where it is as at present standard. In fact, we have suggested that in a new design of distribution box, both the cutout and the auto switch unit be made replaceable, each as a unit, without necessitating the removal of the distribution box base. EFC. | ||