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).
Table of various proposals for a 20 HP dynamo for higher output armature.
| Identifier | ExFiles\Box 68\4\ scan0250 | |
| Date | 28th March 1928 | |
| X5663 28.3.28. TABLE OF VARIOUS PROPOSALS FOR 20 H.P. DYNAMO. FOR HIGHER OUTPUT ARMATURE. 29 28 26 24 No. of slots. Winding 1 Dummy One stage short No or two One stage short (all retro.wave) coil. chord. 1 dummy stages short chord. 1 Dummy lapped in. chording. lapped in. One dummy lapped in. No.of virtual slots, coils 57 56 52 48 or comm. segs. Turns per coil. 4 4 3 3 No.of conductors. 456 448 336 312 288 Total conds. per 16 16 12 12 12 slot. Step or winding 7 6 coil. 6 coil. 6 or 5 coil.7 com. 5 coil 6 com. pitch in slots. 7 com. 7 com. Conductor. .040" .040" .048" .048" .048" Tooth neck. .082" .091" .087" .106" .129" Neck x No.of slots. 2.38" 2.55" 2.44" 2.76" 3.10" Copper area per slot (relative). .0256 .0256 .0276 .0276 .0276 Total copper area (relative). .730 .717 .772 .717 .663 EFC. | ||