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).
Winding specifications for an auto charge control switch.
| Identifier | ExFiles\Box 43\1\ Scan031 | |
| Date | 9th February 1928 | |
| To OY. from EFC. c. Na.{Mr Nadin} X3988 EFC3/T9.2.28. AUTO CHARGE CONTROL SWITCH. XL400E In our EFC3/T3.2.28 we said we would be writing you further and sending some diagrams. Most of the explanation necessary I think you will find in our report EFC2/T9.2.28 which you will receive about the same time as this note. As it may be a convenience, I am attaching a second copy of the connections of the RR. auto switch unit to this note, in addition to the one contained in the main report. We are winding your auto switch with a shunt winding of 32 SWG. D.S.C. the number of turns of which will be approximately 1400, this filling the space to approx. the same degree as in our 12-volt case. We are winding the resistance with 26 SWG. D.C.C. Eureka, arranged to give about 21 turns. it is packed up some distance from the core before the winding is started. The resistance of this will be about 5 ohms. If this resistance is found unsuitable either one way or the other it will be very easy for you to have the winding altered to 24 or 28 SWG. Eureka, as you may decide, keeping approximately the same number of turns. We think the resistance should be such that what we call the second cutting-in, i.e. the cut-in of the dynamo with this resistance in series with the field, should only just occur within the working range of speed. EFC. | ||