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).
Modifications to the Peregrine & Bensport starter motor to improve performance.
| Identifier | ExFiles\Box 179b\1\ img018 | |
| Date | 20th August 1932 | |
| HS{Lord Ernest Hives - Chair}/WST. ) FROM R.{Sir Henry Royce} By E.{Mr Elliott - Chief Engineer} ) C. to SG.{Arthur F. Sidgreaves - MD} WOR{Arthur Wormald - General Works Manager} ...INAL! PEREGRINE & BENSPORT STARTER MOTOR. R4/M20.8.32. X6134 This vigorous little engine is proving rather difficult to turn over the compressions for obvious reasons, but I now understand that there is little doubt about this if we adopt the various modifications already suggested by Derby and WW. The first was to wind the motor with a coarser gauge copper. This increases the volumetric efficiency of the copper in the coil, takes more current from the battery, and naturally will make the motor more vigorous. It was intended however that this should be used with an increase in the gear ratio between the motor and the engine. These two combined will act like compound proportion, and might leave the motor powerful enough, but Derby have suggested that the motor carcase be increased to 4" dia., so as to make a more powerful and efficient motor, which will naturally turn more of the energy of the battery supply into useful work, as well as being capable of taking more energy. These three modifications should easily make a difference of over 100%, which we hope will make this item thoroughly reliable. It will be noted that this ratio between engine and motor cannot be obtained with a crash type of pinion, which would demand a considerable increase in the bulk of the motor, and would lead to a natural decrease in the speed of the motor, both of which we should be sorry to adopt. R.{Sir Henry Royce} A | ||