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).
Revised calculations and modifications for the Peregrine starter motor.
| Identifier | ExFiles\Box 179b\2\ img127 | |
| Date | 17th November 1932 | |
| ORIGINAL X6134 R.{Sir Henry Royce} From HS{Lord Ernest Hives - Chair}/Wat. c. to ES. c. to WGR. c. to By.{R.W. Bailey - Chief Engineer} c. to K.{Mr Kilner} HS{Lord Ernest Hives - Chair}/Wat.4/WA.{Mr Wallis}17.11.32. PEREGRINE STARTER MOTOR. With reference to R.2/M.7.11.32., our original calculations were wrong in that we assumed too high an efficiency for the running working torque of this small motor. This resulted in the number of conductors calculated being too high. Upon revising our calculations as a result of the efficiency figures we have since measured on the small Bosch motor we arrived at a much smaller number of conductors required owing to the lower efficiency assumed putting up the running current. We attach herewith our revised set of calculations also the estimated flux densities at various points of the magnetic circuit. The present motor on the Peregrine is by no means finality as regards performance, as to save time and to get the motor to give a better stalling torque we merely stripped the original armature, cut the slots shallower and rewound with half the number of conductors. Attached blue print shows the performance of the motor with this preliminary modification. HS{Lord Ernest Hives - Chair}/Wat. | ||