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).
Comparing a Bosch starter motor's 'teazer' circuit with other systems, including those on Alfa Romeo and Bentley vehicles.
| Identifier | ExFiles\Box 179\2\ img142 | |
| Date | 1st January 1932 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/wet. c.c. Ev.{Ivan Evernden - coachwork} M.{Mr Moon / Mr Moore} c. Sg.{Arthur F. Sidgreaves - MD} WGT. ORIGINAL Hs{Lord Ernest Hives - Chair}/wet.7/ADS.1.32. X6079 STARTER MOTOR With reference to your RL/M4.1.32, Bosch certainly has a similar teazer circuit to ours and they also now incorporate a safety scheme. This safety scheme is effected, not by means of an electrical hold off circuit but by arranging that the starter pinion has a free wheel ratchet. This means that should the customer hold on the starter button after the engine has fired, i.e. keep the teazer circuit operating, the pinion can freewheel. It would certainly be an advantage if the present standard automatic switch could be simplified in some way by modifying the method of preventing teazer engagement after the motor has started. The original Bosch scheme was to provide a contact at the back of the cut out armature so that immediately the engine started the dynamo cut out would operate owing to the fact that the plain shunt machine used had a very steep voltage speed curve. The operation of the cut out therefore open circuited the teazer circuit and prevented any re-engagement by pressing the button whilst the engine was running. We have removed the Bosch motor from the Alfa Romeo and find this to be very interesting from the point of view of design and will prove helpful in arriving at a suitable design for J.3. and Peregrine. There appears to be no damping feature for the armature, however, and on the large 8-litre Bentley, the armature thumps very badly on coming out of gear - our damper system is a definite advantage. HS{Lord Ernest Hives - Chair}/wet. | ||