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).
Investigation into the failures and causes of issues with the 20 HP starter motor.
| Identifier | ExFiles\Box 40\5\ Scan178 | |
| Date | 24th June 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} OY. c. to Mx.{John H Maddocks - Chief Proving Officer} EP.{G. Eric Platford - Chief Quality Engineer} c. to Hm.{Capt. W. Hallam - Head Repairs} X3587 Hs{Lord Ernest Hives - Chair}2/LG24.6.27. 20 HP. STARTER MOTOR FAILURES. X5650 We have been investigating the various troubles which are experienced in the Test Dept. with the 20 HP. starter motor. These can be placed in the following order :- (1) Sticking of pinion in disengaged position. (2) Pinion crashing on teeth of flywheel and not engaging. (3) Clutch slipping when engaged. In investigating the first condition, we find that the failures are due to three causes - namely - cross-binding effect of the nut, climbing effect of the stop and a slipping clutch. The cross binding of the pinion unit is due to the slackness of the nut on the thread, which has been found necessary for the free movement of the unit. It appears to happen when the two stop faces are not exactly square, which throws the whole unit cross-wise. The binding is not severe but is sufficient to prevent the unit from engaging at the first attempt. The climbing effect appears to be the worst feature. In this case the slackness of the thread allows the unit, upon being returned, to climb up on the face of the stops causing a binding effect of the unit on the thread and faces of the stops, which requires several attempts when starting before being released. To overcome these two contd :- | ||