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).
Comparison table of various starter motors suitable for large cars, detailing their dimensions.
| Identifier | ExFiles\Box 61b\3\ scan0157 | |
| Date | 1st June 1921 | |
| V543 1.6.21. X.543 - STARTER MOTOR TABLES X.3174. (Additional sheet I) (Motors of size suitable for large car) | | X.3247 C.A.V. ZC | X.3161 Lucas A.S1C. | X.1058 Bijur A.21. | X.1248 Bosch S.45. | X.2642 R.R.17 CIC | X.2642 R.R.24 (CIC) | X.2642 R.R.45a (cic) | X.3082 RR.45b (SC) | X.3740 RR.45c (U.S.A. motor). Also RR S.motor for early cars. | X.1058 Bijur A.I.D. | X.4000 U.S.A. Bosch. | X.1086 Westinghouse. | X.4341 C.A.V. | |---|---|---|---|---|---|---|---|---|---|---|---|---|---| | **CARCASE.** | | | | | | | | | | | | | | | Diameter. | 4.500 | 5.650 | 5.500 | 5.900 | Not circular | Not circular | Not circular | 6.000 | 6.000 | 5.500 | 4.850 | 4.940 | 5.000 | | Length. | 5.375 | 3.750 | 7.600 | 4.768 | | | | 5.175 | 4.475 | 7.250 | 5.920 | 5.600 | 4.740 | | Thickness. | .280 | .375 | .275 | .385 | | | | .325 | .325 | .270 | .240 | .300 | .300 | | **ARMATURE.** | | | | | | | | | | | | | | | Diameter. | 2.870 | 3.575 | 3.560 | 3.700 | 3.600 | 3.600 | 3.600 | 3.600 | 3.600 | 3.875 | 3.250 | 3.250 | 3.000 | | Length (active) | 2.800 | 2.050 | 3.000 | 2.870 | 2.550 | 2.550 | 2.550 | 2.250 | 1.575 | 2.670 | 3.800 | 3.300 | 3.050 | | **END CONNECTIONS** | | | | | | | | | | | | | | | Length of overhang at driving end. | .9" | .85" | 1.0" | .9" | 1.3" | .95" | 1.3" | 1.1" | 1.1" | 1.05" | .8" | 1.0" | .75" | | Length of comm. connections. Excluding com. spokes. | 1.45" | 1.0" | 1.05" | .9" | 1.25" | 1.2" | 1.15" | 1.15" | 1.15" | 1.0" | 1.0" | .9" | 1.15" | | Ditto including com. spokes. | 1.7" | 1.2" | 1.3" | 1.05" | 1.5" | 1.45" | 1.4" | 1.4" | 1.4" | 1.2" | 1.2" | 1.1" | 1.4" | Note:- All machines are 12 volt except Bijur A.21 which is 6 volt. (Text in right margin: R.R. 13 (500) (S.L.) 22. 26-8-21. G.1089) | ||