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).
Extract from a conference minute regarding issues with a dynamo's cutting-in speed and interactions with Lucas Electrical Co.
| Identifier | ExFiles\Box 36\4\ scan 214 | |
| Date | 13th June 1921 | |
| X3014b Extract from MINUTES OF CONFERENCE OF 13th JUNE, 1921. DYNAMO X.3014a. X.3014b. X.4060. 43 X.252. X.294. Cutting-in speed. We have for a considerable time complained that the cutting-in speed of the E.575 dynamo is too high. This has been repeatedly mentioned to the Lucas Electrical Co. and they have been furnished with an output curve which we have suggested ought to be attained. Mr. Breeden replied that they originally made a machine complying with the specified curve, but it was rejected by R.R. on account of its weight, in favour of their standard E.575 dynamo which did not comply exactly with the curve. This was confirmed by Mr. Bailey, Mr. Clark and Mr. Hives. Mr. Clark stated that recently the Lucas Elect. Co. have sent us a dynamo identically the same as the E.575, with the exception that it is 1" longer on the armature and carcase. This is now under test and so far as the tests have gone, this machine is a very decided improvement over the standard E.575; the cutting-in speed in our specified hot condition having been reduced from 710 to 540 revs. At the same time, it does not comply with our specified curve in the early stages, the output being about one amp. less on the average between the speeds of 700 revs. and 1200 revs. but as regards heating it is O.K. Mr. Breeden further stated that after our adoption of the Lucas E.575 dynamo he, in response to our demands, designed a special concentric type, 4 pole dynamo, of the same overall dimensions as the present E.575, with the object of complying with the output curve submitted by us. They made three of these machines, and, after repeated tests, found that they could get them to comply with the curve, but that they could not make them silent. They thereupon resorted to lengthening the present E.575 machine by 1", in order to have a machine which was not so seriously stressed electrically. | ||