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).
Specifications for two new field windings for the Phantom III dynamo to increase resistance.
| Identifier | ExFiles\Box 168a\3\ img479 | |
| Date | 12th March 1938 | |
| 6142 BY/RD.1/B.12.3.38 PHANTOM III DYNAMO : FIELD WINDINGS - SEC. S100. (6.5 Ohms required). In order to obtain a slight increase in the resistance of the field winding on the Phantom III dynamo, we wish to try two new windings. Will you please order the two types of winding wire specified below, and build up one set of field coils from each type of wire. These coils to be fitted in turn to an existing dynamo in the possession of Rm{William Robotham - Chief Engineer}/RC.{R. Childs} Prices per lb., for 1000 lb lots, should be obtained for each winding wire. 19 SWG. (.040 dis.) Specially Fine D.C.C. Copper Wire - Dis. over insulation not to exceed .0475 - 7 lbs. 19 SWG. (.040 dis.) Enamelled and Specially Fine S.C.C. Copper Wire - Dia over insulation not to exceed .0475 - 7 lbs. The two coils should be built up to the production arrangement D.75275, except that the number of turns should be as many as possible. (At least 276 turns). The remaining material required for these two windings is :- Egyptian Tape .005 x 12 mm. 140 Ft. 40/36's Cable. Spec. 260A. 18.000 D.70710 Cable Eye. 4 off. all of which is production material. The resistance of each winding should be taken, and we hope to get at least 6.5 ohms required by the regulator. BY/RB.{R. Bowen} | ||