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).
Experimental tests of the Peregrine starter motor, comparing two different armatures.
| Identifier | ExFiles\Box 62\1\ scan0105 | |
| Date | 12th January 1933 | |
| X6134 - E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Wst. c. to By.{R.W. Bailey - Chief Engineer} c. to Wor.{Arthur Wormald - General Works Manager} c. to Sg.{Arthur F. Sidgreaves - MD} Hs{Lord Ernest Hives - Chair}/Wst.6/KT.12.1.33. PEREGRINE STARTER MOTOR. We have now completed experimental bench tests and chassis tests with a Peregrine starter motor, in which we have tried two experimental armatures. The armatures in question were to D.100364 and D.100427 respectively. We attach herewith curves showing the torque, ampere and B.H.P. characteristics of the motor fitted with each armature. An examination of these curves shows that the 29 slot armature gives the highest B.H.P. figure, but at the expense of a heavy current. This current would only operate for a very small period of time, however, as immediately the motor speeds up, the efficiency increases rapidly thus lowering the current. Neither of these two armatures gives the maximum efficiency we are anxious to attain, which we consider is explainable by the fact that in the 29 slot armature we have reduced the number of conductors to too low a figure, whereas in the 19 slot armature we have not reduced them enough for a substantial reduction in armature resistance and increase in iron to be gained. We propose to review our calculations in view of the results obtained, in order to ascertain what further improvement can be effected in the armature circuit. The power output of this little motor is now very satisfactory, and it now remains for us to make it more efficient. Actually our maximum B.H.P. is .91 with the 29 slot armature to D.100364, as against .80 on the Bosch, but the Bosch maximum efficiency is .54 as against .44 on the R.R. motor. We have also examined the field circuit of the Peregrine motor, and hope to issue our recommendations for improvement in this direction also, shortly. The engagement of the Peregrine motor with the flywheel gear ring is not satisfactory for the following reasons :- | ||