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).
Specifications and test results for the revised Starter Motor A.2.
| Identifier | ExFiles\Box 64\1\ scan0256 | |
| Date | 1st December 1926 | |
| x7620 EFC. EFC4/T1.12.26. STARTER MOTOR A.2. The following are details of A motor, revised and designated A2:- This machine has the deep slot type armature taken from C machine, with the carcase, poles and field windings of A motor. Particulars. Poles with reduced cores. Teazer winding 36 turns per pole, 17 SWG. placed near the carcase. Resistance of winding taken between the terminals .409 ohms at 45°C. Resistance of main winding taken between terminal and positive brush holders. .0185 ohms at 45°C. Resistance of armature winding and brushes .0168 at 18°C .0127 ohms at 45°C. Resistance of armature winding measured from one commutator segment to another at 90° .0078 at 18°C .0086 ohms at 45°C. Shaft thread = 20° spiral. (i.e. 70° helix). Reduction gear on motor = 96 to 31. Motor pinion to flywheel = 65 to 9. Total reduction = 22.37 to 1. Light Test. Teazer. { (Speed at 12 volts (cold). 720 r.p.m. { " " 20 amperes. 806 r.p.m. Main. { (Speed at 6 volts (cold). 1750 r.p.m. { (Amperes at 6 volts. 20.0 ~~r.p.m.~~ Crawling Torque. { (Teazer torque for 20 amperes 18.37 lb-inches. { (Main torque for 100 amperes 112.5 lb-inches. { " " " 120 amperes 139.5 lb-inches. Running Torque. { (Torque at 1500 r.p.m. for 100 amps. 94.87 lb-inches. { " " " " " 120 " 129.70 lb-inches. EFC/HEW. | ||