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).
Suggestions for a damper attachment to a starter motor for silent operation.
| Identifier | ExFiles\Box 64\4\ scan0153 | |
| Date | 25th December 1928 | |
| X7655 X7770 Extract from FL/M25.12.28. X7625 STARTER MOTOR. I am sending Mr. Elliott some suggestions for a damper attachment to the rear end of the starter motor to enable the end motion to finish silently. The other features are only a matter of proportions of end pull and spring pressure. I repeat my suggestions of (1) returning to a parallel armature, (2) a hold out spring of lowest possible rating (even pull) of about 25% = a quarter of the weight of the armature, (3) a kick-back spring of very small initial pressure and fairly high rating - (these are only suggestions, and others should be tested.) The dashpot I have schemed allows say 75% of the stroke undamped that can be done quickly, and the remaining 25% allows for the slow coming to rest of the armature endways in each direction. The design only affects the rear end bearing, so is a small item of the starter equipment. (See sketch with original) E.{Mr Elliott - Chief Engineer} is quite right about the crossing of the teeth, but I think if they can get in 50% of the angular time they will do, so when the kick-back spring and torque is made more suitable perhaps a few more teeth in the pinion would do good to the gear - not much harm. In addition I suggest rather coarser teazer winding for greater vigour of end pull and torque - i.e. make it feeble enough and it will stick wherever placed. | ||