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).
Comparing a C.A.V. cut-out to a Lucas fitting and discussing constant current versus constant voltage electrical systems.
| Identifier | ExFiles\Box 61\2\ scan0083 | |
| Date | 27th October 1914 | |
| X.3374 To Na.{Mr Nadin} from R.{Sir Henry Royce} c. to J.{Mr Johnson W.M.} c. to Wor.{Arthur Wormald - General Works Manager} for Mr. Ellis. c. to Bv. EFC R10/IB27.10.14. X. 206. X. 3374. X. 1357. X.1610.-C.A.V. CUT-OUT. With reference to the C.A.V. cut-out, this seems to be a decently made fitting, far different to the earlier one I saw that was sent to us by these people, which was a disgrace to any firm. It is, however, very heavy and a separate fitting and not nearly so light and neatly carried out as in the case of the Lucas, which includes the cut-out in the switch board. The Lucas fitting appears to work with great satisfaction. I have noticed that the cut-out and cut-in of the battery is a much easier job with a constant current system, such as the C.A.V., Lucas, Ward Leonard and others. The reason for this is, that if the automatic switch does not cut in, the potential rises very considerably owing to the winding of the dynamo, and any increased speed above the minimum will almost certainly force the automatic switch to cut-in, and as the reverse current throws the automatic switch out, the whole apparatus need not act with very great precision. This, however, seems not to be the case with the constant voltage system in any case, unless the automatic switch is very carefully regulated it may not cut in. Our own ideas on the subject are that the system ought not to be either a constant current one or a constant voltage one, but that the current should be reduced as the voltage of the cells increases, and the voltage regulator should, therefore, be compound wound. (Contd). | ||