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).
Test results and performance curves for the Smith (T & M) Type A Dynamo.
| Identifier | ExFiles\Box 3\5\ 05-page169 | |
| Date | 5th March 1920 | |
| X 295 To R.{Sir Henry Royce} from Ck.{Mr Clark} c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to Bm. c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Dal c. to Hs.{Lord Ernest Hives - Chair} CK{Mr Clark}6/T5.3.20. X.295 - SMITH (T & M) TYPE A DYNAMO Further to our EFC1/T13.8.19, we now attach a sheet of curves representing the E portion of the tests on the Smith type A dynamo referred to therein. These give the out-put speed curves of the machine arranged in various ways, (a) (b) (c) (d) as below, and set to charge a six cell battery. (a) as a plain shunt machine (both control brushes removed). (b) one control brush only in action. (c) correctly connected. (d) equal small resistances in control circuits. It will be noted from these curves that the cutting in point in the controlled condition is a little later than as a plain shunt wound machine, which is not the case in the C.A.V. or Lucas dynamos. This is to be explained by the fact that in this scheme of control, so much of the armature is short-circuited that the voltage, however, is considerably reduced. It will be further noted, that the rise of current with speed is so rapid that the characteristic curve crosses that for the simple shunt case and recrosses it again later, whereas in the case of the Lucas E.575, the curve for normal connections crosses the shunt curve once sent to us by Messrs Smith & Co Ltd. Contd. | ||