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).
The performance tests of a slow speed servo motor, including torque ratio, mechanical efficiency, and deflection.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan135 | |
| Date | 25th March 1924 | |
| R.R. 493A (40 H) (SL 42 12-7-23). J.H., D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. 9940 REF: Hs{Lord Ernest Hives - Chair}/ACL1/LG25.3.24. EAC.111. SLOW SPEED SERVO MOTOR W.W.3. The following tests were made on the servo fitted with 35º actuating thread. (1) Determination of the ratio of total torque given out by servo (available for braking) to the torque applied. The tests were made at a car speed of 30 m.p.h. with loads equivalent to pedal pressures of 17 to 150 lbs. The ratio torque given out / applied torque varied from 3.47 with 17 lbs. pedal pressure to 1.56 with 150 lbs. pedal pressure, an average value being 1.8. This ratio calculated from the LeC. drawing should be 3.19. For the Hispano, this ratio has an average value of 4 (by experiment). As the torque given out by this servo is equal to the sum of the applied torque and the friction torque, the friction torque is equal to 0.8 for the average value. (2) Mechanical efficiency of the actuating thread (well lubricated) When in motion the mechanical efficiency was 98% but a greater load was required to start movement which reduced the efficiency to 65.5%. (3) Deflection of the outer servo plate under load. [Diagram Text] DRIVEN PLATE ANNULAR GROOVE OUTER PLATE LOAD FERODO DISC | ||