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).
Explanation of the dynamo-battery system, detailing the function of the danger lamp under various fault conditions and the cutout coil connections.
| Identifier | WestWitteringFiles\R\2October1927-November-1927\ 45 | |
| Date | 18th April 1925 guessed | |
| -6- Contd. (3) An open circuit on the dynamo-battery system for which no current is shown by the ammeter. Again, charge must be switch/off. On the supposition that it is either (2) or (3), as soon as the dynamo is switch/off again, the lamp will go out, but if the lamp does not go out then it is (1). The danger lamp is arranged to be supplied through the danger unit contacts from a point as near to the positive terminal of the battery as reasonably possible, but to retain protection against an accidental earth on the supply wire we have put this on the top side of the main fuse. That means that if the open circuit occurs in the battery itself or main fuse, the lamp will be lit from the dynamo and probably burn out in the daytime. (N.B. The high voltage of the dynamo will keep the cutout contact on contact). We have, however, avoided the burning out of the danger lamp as a result of a broken connection anywhere else in the circuit by making the circuit of this danger lamp quite independent of the circuit of the relay, in fact by using four terminals on the unit. Even so, it appears to us that such a unit is not so safe in emergency as the auto-switch. Before passing over to the consideration of the auto switch, we wish to refer to the connection of the shunt coil of the cutout, viz. COSH, (the series coil being labelled COSE). This we have shown connected in the way which we have recently described as being preferable to the standard connection, viz. as being fed through the field fuse from the Contd. | ||