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).
The bench testing of a modified Bentley starter motor for increased stalling torque and improved cold starting.
| Identifier | ExFiles\Box 62\1\ scan0248 | |
| Date | 30th April 1934 | |
| Hs{Lord Ernest Hives - Chair}/Wst.1/WA.{Mr Wallis}30.4.34. BENTLEY STARTER MOTOR WITH INCREASED STALLING TORQUE FOR BETTER STARTING FROM COLD. We have now tested on the bench one of the new motors to R.R.Sch.508 produced in order to increase the engine speed when cold and also to increase the stalling torque of the motor. When first produced the motor only had a very small increase of power over the present standard Bentley motor to R.R.Sch.399. The reason for this was that the field winding was inadequate and another field winding was instructed to details DB.{Donald Bastow - Suspensions}626 having increased section of copper and also having one more turn per pole. The net result of this was to increase the magnetisation of the motor considerably without any increase in the total ohmic resistance. With the modified field winding the starter motor gave very much increased power and stalling torque performance and the results of the bench tests are shown on the attached curves which have for comparison a standard Bentley starter motor to R.R.Sch.399 shown dotted (BHP. only). The stalling torque increase is approximately 42% and this is maintained with very little reduction right up to the maximum BHP. point. This motor has now been fitted to a Bentley Chassis for cold starting tests etc. Hs{Lord Ernest Hives - Chair}/Wst. Starter Motor Test Report Attached to By's copy only. | ||