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).
Continued discussion on the design of a starter motor, covering push-button operation, winding specifications, and potential jamming.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan056 | |
| Date | 17th August 1926 | |
| To R.{Sir Henry Royce} Contd. ----------------- -2- EFC2/T17.8.26. ----------------- end pressure from the solenoid. It has always appeared to me that we have got to use a comparatively heavy teazer current to be safe in all circumstances, and the contact for which may not be reliably made by a hand push button, therefore I have thought that the push button ought to be foot-operated because we are so much more certain that way of getting the effective copper contact against the strong spring. Then again, any tendency of a foot-operated push button to remain on contact longer than a hand-operated one will be accommodated by the particular feature of this silent starter. You may remember that we have already increased the winding gauge of the actuator and teazer windings from 18-SWG as originally arranged, to 17-SWG, and it may still be that for winter conditions, apart from any jamming, we have to go still further than this, say to 16 SWG., still further increasing the actuating current which has to be carried by the push button contacts. Previous to putting on the car, we had considered the action of the whole thing and had ourselves come to the conclusion that we could not see how it could fail to engage, i.e. how it could jam, unless it got into one particular but unlikely position in which the resultant force between the pinion tooth and wheel tooth were normal to the direction of the helical thread, and provided, as you say, the teazer was sufficient to turn the motor without load. Our apprehension was on the core of that latter condition, but as previously Contd. | ||