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).
Calculations and proposed alterations for a new sequence starter motor.
| Identifier | WestWitteringFiles\P\October1926-November1926\ Scan144 | |
| Date | 27th November 1926 | |
| To AJS. from EFC. c. BJ. BY.{R.W. Bailey - Chief Engineer} ORIGINAL EFC1/T27.11.26. RE SEQUENCE STARTER. V620 We regret we have not been able in our previous note to give you the complete information asked for in your AJS1/M9.11.26. We are now in a position to do this. It appears from our calculations, that for this new 13 to 1 ratio we can do very well with the present New PhantomCodename for PHANTOM I starter motor armature with the number of slots and windings as at present, but that it will be necessary considerably to reduce the number of turns of resistance of the main series field winding for satisfactory results. The number of turns will be 3 1/4 per pole in place of 6 1/2, and the section, the maximum possible we can get in. In looking over previous results, we have noticed, as would really be expected, that low efficiencies at high torques always occur when there is a big ratio of field resistance to armature resistance. As this motor has to work efficiently at a much higher torque, this change will be very necessary, and there is little doubt that a motor arranged with this change, but otherwise similar, will shew a much better brake efficiency performance on the bench than we have obtained on the present Phantom motor. As the change is comparatively small, I am proposing to put in hand for experimental test a motor with this alteration and to obtain the brake efficiency test results as soon as possible. We hope to be able to send you more detailed information and | ||