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 and operational tests on a starter motor, its armature, and teazer circuit.
| Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan159 | |
| Date | 1st March 1929 guessed | |
| contd :- -2- the only appreciable noise in each [illegible] direction being the slight click when in each case the armature takes up a solid connection to the piston. (3) An electrical operation test. The motor still being held in the brake test bench clamps (with no wheel for the pinion to engage into) the effect of switching on and off the normal voltage to the teazer circuit (teazer + main + armature) was noted. The operation was disappointing compared with the operation of the taper armature motor with 18 S.W.G. teazer winding previously observed. The motor accelerated too quickly rotationally and not sufficiently longitudinally. In most cases the armature did not reach even the stage of taking up solid with the piston before the rotational velocity had increased and reduced the current unduly. Ultimately the armature spun very fast and dropped back almost to its initial position. This performance is very different from that noted on the 3.100 to 3.000 taper armature with 18 S.W.G. teazer in which case there was in similar circumstances a definite bump to the outer stop. In so far as the operation called upon the services of the damper to prevent longitudinal knock, the damper was observed to be effective. (4) An operation test on the starter motor rig previously referred to :- Teazer current operation, main current off :- Motor advanced into gear most times, (i.e. only failed by corner jamming comparatively rarely) but produced an appreciable rotational knock on the teeth, due to the vigorous torque. The longitudinal tooth friction under the action of the torque prevented the armature from advancing sufficiently far to operate the main switch contact except occasionally and then only just. On switching off, the armature would return to out of gear position definitely and practically noiselessly. Operation with main current on :- in cases in which the main switch operating circuit was made, the motor would proceed to turn the crankshaft (against the same brake or suitable amount as in previous tests) but without complete engagement and on attaining a speed corresponding to rolling a hot and easy engine, the longitudinal hold in on the reduced main current became too weak, the contact was broken and the motor dropped out (press button still on and hold off coil only in action). We appear now to have experienced very nearly completely satisfactory operation in parts, i.e. in different motors, and switches, but not yet to have put up a single system incorporating all good features together. We are arranging for a return experimentally to the taper armature, in fact, at the time of writing contd :- | ||