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).
Electrical quantities and torque specifications for a 20 HP starting motor.
| Identifier | ExFiles\Box 50\2\ Scan082 | |
| Date | 5th May 1919 | |
| X4298 To EFC. from E.{Mr Elliott - Chief Engineer} c. to CJ. c. to Bn.{W.O. Bentley / Mr Barrington} c. to Da.{Bernard Day - Chassis Design} c. to EH. E5/G5.5.19. X.3534. 20 H.P. STARTING MOTOR. X.3009. ---------------------------------------------------- In getting out the electrical quantities for the 20 H.P. starter motor, would you kindly note that the speed of the motor is supposed to be 3,000 revs. per minute when starting the engine, and the overall reduction on the gearing of 48 to 1. We took the starting torque for the 20 H.P. engine to be 450 lbs. inches at the crankshaft, this figure being pro rata with the 40/50 H.P. chassis at 900 lbs. inches, the basis of comparison being the relative displacement of the engines. E.{Mr Elliott - Chief Engineer} | ||