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).
Summary of a visit to Messrs Lucas to investigate and discuss dynamo regulator troubles and specifications.
| Identifier | ExFiles\Box 166\2\ img169 | |
| Date | 11th February 1938 | |
| By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/RC.{R. Childs} c. By/RD. 6092. Rm{William Robotham - Chief Engineer}/RC.{R. Childs}1/AP.11.2.38 Re. Visit to Messrs Lucas (7.2.38) In order to investigate regulator troubles Rm{William Robotham - Chief Engineer}/CAP. and myself visited the works of Messrs Lucas and discussed the subject with Mr.C.E.Robinson, their regulator expert. The following is a summary of the discussion. Our present regulator in its early form, known as the B.2.CJ1, had a setting of 15 to 15.5 volts, and had a series compensating winding of 3 turns. The resulting dynamo output at 13 volts being 9.2 to 13.0 amperes, which is too low. In November 1937, this setting was altered to 15.3 - 15.8 volts, in order that the load should comply to our specification, namely:- Output at 13 volts. Output at 15 volts. Cold 14.0 - 16.5 amps. 1.0 - 7.5 amps. Hot 15.0 - 18.5 amps. 3.5 - 10.5 amps. In this form it represents our present standard and is known as the B.2.CJ.1.A. type. Our specification is now considered to be too low, and we find our requirements are in the neighbourhood of 19.0 amperes at 13.5 volts. For experiment, we obtained from Messrs Lucas three regulators with a higher setting, namely, 15.8 to 16.4 volts; these will supply a load of 19 to 19 1/2 amperes at 13 volts, when in a hot condition, but even this will not entirely balance the probable load when running at night. However, we have ordered six more of this type for trial on the road. The only alternative to this, is a regulator with 2 1/2 turns instead of three on the series compensating winding, coupled with the higher setting. This will give a mean load of 19 amps at 13.5 volts, which we estimate will meet our requirements. Messrs Lucas are setting two of these units for use, and we will, on receiving them, carry out a road test. In the case of the P.III. chassis, an improved dynamo will be required in order to give the increased load without undue sparking at the higher speeds. In view of the fact that the C.A.V. Co. are not making this type of regulator now, it will take a week or two to get things moving, it will also incur extra cost for continued. | ||