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).
Modifications and tests on electrical motor components and switches.
| Identifier | WestWitteringFiles\T\2January1929-June1929\ Scan164 | |
| Date | 22th February 1929 | |
| contd :- -4- 8. Main armature spring D.71569 with .125" packing to give a spring + packing set up length of 3.700" and force of 5.05 lbw. 9. Pinion clearance from wheels in disengaged position to be .175" i.e. equal to the damper travel and set of spring reduced to low value by shortening spring. Regarding your R4/M22.2.29. We have brushes to hand with less copper and more carbon, though this does not now seem of such critical importance. A test will be made.xxxx Some time back, we got out and called for a still longer and lower rate spring than the one at present in action. This is not yet available. The two-way push button switch has rendered impossible the motor continuing to turn engine when button is released. No case of non-return of armature has been noticed on recent tests. Press button is not yet quite right, it takes too much pressure to operate and is a little difficult to correct in the new and compact design. Main switch is promising but one difficulty has been the inertia lag of the carbon arm causing the copper to make first. Again a (copper arm - carbon arm) spring of lower rating and greater set is indicated. EFC. | ||