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).
Armature losses in three types of narrower brush EAC dynamos.
| Identifier | WestWitteringFiles\O\2April1926-June1926\ Scan225 | |
| Date | 21th June 1926 | |
| To R.{Sir Henry Royce} from EFC. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to Da.{Bernard Day - Chassis Design} E.{Mr Elliott - Chief Engineer} c. to Rg.{Mr Rowledge} By.{R.W. Bailey - Chief Engineer} c. to EP.{G. Eric Platford - Chief Quality Engineer} ORIGINAL EFC3/T21.6.26. X.8671 EAC.DYNAMO OF THE NARROWER BRUSH TYPE. As referred to in our EFC3/T27.5.26, we now give three blueprint pages of curves of the observed armature losses in the three machines - (1) Present standard. (2) Narrower brush and wider air gap machine. (3) " " " " with thinner armature plates. The curves shew the magnitudes of the various losses on a speed base. In other respects the curves are self-explanatory. The mechanical brush friction in all machines is very much the same. The hysteresis loss suffers a distinct drop from the standard machine to the other two, the loss for which is practically the same. The eddy and circulating current losses suffer a fair drop from the standard machine to the N.B. machine, and a still further drop from the N.B. to the N.B. with thinner armature plates. The brush short circuiting current losses suffer a big drop from the standard machine to the N.B. machine, and are about the same as this latter for the N.B. machine with thinner armature plates. In addition there is attached a sheet shewing the development of a formula for the variation of the combined eddy current and hysteresis losses of the three machines with speed. These N.B. machines shew good promise of being in actual use a good deal electrically quieter than the present standard. EFC. | ||