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).
Continuation of starter motor comparison tables for 40/50 HP size, Group A models.
| Identifier | ExFiles\Box 61b\3\ scan0197 | |
| Date | 10th November 1927 guessed | |
| -2- Starter Motor tables Contd. 40/50 HP. size. Group A.{Mr Adams} MOTOR: X.3247 C.A.V. ZC. | X.3161 Lucas A.510. | X.1058 Bijur A.21. | X.1248 Bosch S.45. | X.2642 RR.17. (clc.) | X.2642. RR.24. (clc.) FIELD CIRCUIT No. of wound poles: 4 | 4 | 4 | 4 | 4 | 4 Size of conductor: - | - | - | - | .370 x.056 | .370 x.056 No. of turns per coil: 6 | 18 | - | - | 13.5 | 13.5 Arrgt. of coils: 2 S. 2 P. | 4 in P. | 4 in P. | 4 in S. | 4 in S. | 4 in S. Resis. of field circuit (ohms at 18°C): .0039 | .0028 | .0012 | .0030 | .0204 | .0204 ARMATURE CIRCUIT Type of winding: Ret. wave 2 circ. | Ret. wave 2 circ. | Ret. wave 2 circ. | Prog. wave 2 circ. | Ret. wave 2 circ. | Prog. wave lap 4 circ. No. of slots: 21 | 43 | 21 | 41 | 17 | 24 No. of conductors: 84 | 86 | 84 | 82 | 102 | 384 Conductors per slot: 4 | 2 | 4 | 2 | 6 | 16 Coils per slot: 1 | 1 | 1 | 1 | 3 | 2 No. of coils or comm. bars: 21 | 43 | 21 | 41 | 51 | 48 Turns per coil: 2 | 1 | 2 | 1 | 1 | 4 (2 S 2 B) Virtual conductors: 42 | 86 | 42 | 82 | 102 | 96 Winding pitch in virtual conductors: 9&11 | 21 | 9&11 | 21 | 25 | 25 frd. 23 bck'd Step or winding pitch in slots: 5 | 11 coil 10 com | 5 | 11 coil 10 com | 4 coil 4&3 com | 6 coil 5&6 com Size of conductor sq. inches: - | - | - | - | .0078 | - Resis. of armature circuit between appropriate comm. bars. (ohms at 18°C): .0086 | .0084 | .0016 | .0095 | .015 | .0195 Ratio of field resistance TO ARM. RESIS.: .453 | .333 | .750 | .316 | 1.36 | 1.046 | ||