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).
The Lucas M45G motor rubber drive and an evaluation of various starter main switches.
| Identifier | ExFiles\Box 168a\4\ img198 | |
| Date | 22th April 1941 | |
| Rm{William Robotham - Chief Engineer}/RC.{R. Childs}8/ET.22.4.41 - 4 - Electrically, the Lucas M45G type motor is suitable for all rationalised models, including the B.80. The weak link is in the rubber drive which, at the moment, is not good enough for the B.80. Messrs. Lucas are now fully aware of the trouble and have promised us a better drive. We have not received any yet. The Lucas M45G type motor has been fitted to the following cars:- 9-B-V (B.60) 1-RI-1 (B.40) B.80 No.6 B.50.LS (B.II) { see Rm{William Robotham - Chief Engineer}/RC.{R. Childs}1/WH.26.5.39. 6-B-IV (B.II) { The rubber drive failed on 9-B-V after 4920 miles. We recommend the Lucas M418G type for the Myth. This is as fitted to Rover 10, M.G. Midget, Sunbeam Talbot 10 and Vauxhall 10. We recommend a Bendix drive as used on the Sunbeam Talbot. STARTER MAIN SWITCH (D.C.D. 1109 Std) - The standard switch is very reliable and we have had no complaints during the last twelve months. It is, however, rather costly, and attempts have been made to cheapen this unit by omitting the carbon contacts and simplifying the armature and yoke. One unit was made up by HPS{Horace Percy Smith - Experimental Factory Mgr}/TT. and another of this type detailed by Ry/RD. to DCD.123. We find that, unless adequate contact pressure exists, intermittent failure will result. We have had intermittent failures on both the HPS{Horace Percy Smith - Experimental Factory Mgr}/TT. switch and the DCD.123 type, due to oxidation of the contacts. We have, however, a switch in view for the Myth in the standard Lucas ST.900 solenoid switch. The S.T.900 switch has a contact pressure of 9 lbs. against only 2 lbs. on the hinged type switch to DCD.123. The ST.900 has completed an endurance test of 15,000 operations under working conditions without showing any sign of failure (Rm{William Robotham - Chief Engineer}/RC{R. Childs}1/JH 26.1.38). This switch may be mounted on the carcase of the motor, if desired. | ||