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).
Brush and pole positions for Goshawk & EAC dynamos.
| Identifier | ExFiles\Box 51\1\ Scan319 | |
| Date | 6th December 1923 | |
| EFC. {E. Fowler Clarke - Electrical Engineer} AB.95. X.4383 6th Dec. 1923. X.4383. RR. DYNAMO BRUSH & POLE POSITIONS. X.9660. Herewith a rough diagram indicating the average relation of poles and brushes with the armature neutral of GoshawkAero EngineCodename for 20HP Car / Aero Engine after KestrelAero Engine & EAC. dynamos. The control brush position given for the GoshawkAero EngineCodename for 20HP Car / Aero Engine after KestrelAero Engine is the average which occurs on machines set to the production test, these being about 8¼ clear segments between the adjacent faces of the positive and control brushes. The position given for the EAC machine is the average found on the dynamos so far tested when set to comply with general specification. In this case, the spacing between the adjacent faces of the positive and control brushes is about 8½ segments. The angles given on the rough diagram refer to the centre lines of the brushes and poles. The widths of the brushes in relation to one commutator segment taken as unity in each case are :- GoshawkAero EngineCodename for 20HP Car / Aero Engine after KestrelAero Engine. Main, 1.32 or 16.4º Control .88 or 10.9º E.A.C. (Handwritten above: 1.576 18.9º) Main 1.47 or 17.6º Control 1.15 or 14.3º 1 com. seg. + insulation = 12.4º on each machine. F.J. Allen. | ||