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 specifications for various starter motors, continued from a previous page.
| Identifier | ExFiles\Box 61b\3\ scan0201 | |
| Date | 10th November 1927 guessed | |
| -3- Starter Motor Tables - Contd. MOTOR. X.2642. RR.45a clc. | X.3082. RR.45a. clc. | X.1058 Bijur I.A.D. | X.4007 U.S.A. Bosch. | X.1086 Westinghouse. | X.4341 C.A.V. S.B. MAGNETIC CIRCUIT. Air gap (inches) | .025 | .025 | .022 | .019 | .035 | .050 COMMUTATOR & BRUSHES. Commutator dia. | 2.436 | 2.400 | 2.083 | 1.544 | 1.790 | 1.780 Comm. length. | 1.250 | 1.250 | 1.187 | 1.150 | .969 | 1.125 Grade & hardness of brushes. | CM1. Morgan-ite. | CM.3. Morgan-ite. | Metite N More metallic than CM.3. | CM4. Morgan-ite. | SPEER K.K.K.K. Similar to CM3. | CM0. Morgan-ite. No. of brushes. Arrgt. of brushes. | 4 at 90o | 4 at 90o | 4 at 90o | 4 at 90o | 4 at 90o | 4 at 90o Brush contact total area for current(sq.") | .75 | .75 | .492 | .660 | .548 | .478 Advance or retard of brushes. EFC. | ||