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).
Sluggish motion and lubrication issues in sequence starter motors, comparing different designs.
| Identifier | ExFiles\Box 179\2\ img283 | |
| Date | 27th February 1932 | |
| ORIGINAL To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Wst. c. Sg.{Arthur F. Sidgreaves - MD} Nor. c. E.{Mr Elliott - Chief Engineer} De. c. Ry. Y543 X6079 SEQUENCE STARTER MOTOR TROUBLES. We have found that the chief difficulty experienced with these motors in service and on experimental chassis has been sluggish longitudinal motion when working on the "teazer" slow motion circuit. We have proved that this sluggish motion has been due to two things, namely, over-lubrication of the motor and sliding gear friction when going into full engagement. With the motor connected to the Bijur oil supply, in spite of the fact that small gauge plugs are used, we find that the bearings tend to get oiled excessively, the excess oil getting on the commutator causing excessive brush friction due to the carbon dust mixing with the oil and forming a gummy paste. Also in cold weather we have found coagulation of the oil in the bearings has occurred sufficient to prevent full engagement on the "teazer" circuit. We have tried self lubricating bearings containing graphite as used by Delco-Remy and Lucas with very little success, their conditions being different to ours in that their Bendix type motors rotate only and there is no sliding action in the bearings. The increased frictional effect over the small periods the motor is used is therefore negligible compared with the main motor torque. We have found on the Bosch motors which have used the sliding armature principle of engagement for over 10 years that the bearings have no outside method of lubrication i.e. there are no lubricating caps but the driving end bearing is lubricated by means of a spring loaded felt pad let into the bronze bearing bush and fed from a reservoir of oil saturated cotton wick packed in a circular cavity all round the bearing. The commutator end bearing simply relies on the initial supply of grease smeared on the bearing and a certain amount of surplus grease which percolates from the spring barrel inside the armature shaft. These motors work very satisfactorily as regards sliding motion and the bearings maintain their lubrication. We are trying experimentally a similar scheme of lubrication on our own sequence motor as we wish to make our motor self-lubricating and waterproof which, of course, entails blocking up all oil drain holes etc. | ||