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).
Notes on dynamo windings, ignition coils, and comparisons of various magnetos.
| Identifier | ExFiles\Box 4\5\ 05-page174 | |
| Date | 31th March 1921 | |
| Contd. -3- E1/G31.3.21. (l) Mr. Clark to get out the winding with even number of teeth and dummy coil, and a moderate number of teeth, so as to use punched plates and avoid milling. This should give us a silent machine and good insulation to earth by grouping coils. (m) The radial air space for R.R. machines should be as follows :- 6" dynamo .015 5½" dynamo .012 5½" motor .015 4½"motor .012 (n) Also dynamo should have spiral teeth and gentle approach of poles for silence, spirally castellated or knurled shaft with identical armature punchings located on top of teeth. (o) Mr. Clark to take the Bosch ignition coil back with him and find out why the Bosch ignition set can be sold at a price of £3.15.0 while R.R. coil costs £4.10.0 (11) Mr. Royce thinks we shall have to stick to the Watford Company, but get them to improve their machine. He thinks the sleeve is a very good device to use, and that its effect on the controls is negligible. The B.T.H. sleeve machine should be tested on a car. Have since noticed Watford appear to have their armatures wrongly timed with the break. The minimum break speed should be between the central and retarded position; they have it in the advanced position. Sleeve one is quite O.K. and very good. We do not want extra weight and cost. (12) Robert Bosch (German) and Conner (English) seem the best magnetos offered, though the sleeve Watford, B.T.H. and also Dixie (inductor type) are excellent for slow running. We understand the American Bosch broke down and another had to run at 520 revs. in retarded position; out of three there was one good one. (Kindly confirm or contradict this promptly - F.H.R.). E.{Mr Elliott - Chief Engineer} See O.I.C.7606 VOL H FILE R.R | ||