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).
Preliminary bench tests on switch units and actuator box components.
| Identifier | ExFiles\Box 64\3\ scan0021 | |
| Date | 7th November 1924 | |
| Contd. -2- EFC3/T7.11.24. Preliminary tests made on the bench with the switch units in mechanical adjustment carefully considered to be suitable, and with windings as originally arranged, indicated two things :- (12.5 amperes at 11 volts) (1) That the teazer circuit current was of insufficient magnitude to provide sufficient torque in the preliminary stage to turn the motor previous to making the actuator box contact. (2) That the strength of the hold-on coil, although sufficient in most cases, would not allow sufficient margin against contingencies such as the coil being hot and the battery voltage low. not On these bench tests we could/judge the operating qualities of the gear meshing, but the actuator box was arranged so as to push away a heavy suspended weight which upon its return would imitate the starting of the engine, by returning the actuator box plunger to its original position, and except for the two points mentioned above, other features app were found to be O.K. It was then arranged to put this on the chassis but it was known that under any condition the motor would not be certain of starting. It was, however, a comparatively simple matter to put in a bye-pass resistance (located under the base of the combined main and relay switch unit) forming a shunt across the actuator box and motor teazer windings in series. This bye-pass resistance was actually connected to two of the terminals under the base, and its electrical location is shown on the attached diagram as a pencilled line. This, without appreciably altering the strength of the actuator box and teazer winding excitation, each element of which had | ||