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).
Design and lubrication of a starter motor dashpot, including motor brushes and teeth engagement.
| Identifier | WestWitteringFiles\T\January1929-February1929\ Scan174 | |
| Date | 22th February 1929 | |
| FROM R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence.) REC'D AT WW. 25.2.29. SS.{S. Smith} STARTER MOTOR DASHPOT. X7625 The 3 specimens I have seen of the above hardly justifies fitting a dashpot, and when we add the extra for the lubricating pipe there becomes too much of it. Naturally we must lubricate the motor bearings (but I am not sure if I have written about this.) I intended to suggest there should be a pipe coming to the main bearing with perhaps two restrictors on to each bearing, one on each bearing casting, and thus let the dashpot be fed by drainage. These could be on steel carcase. [Diagram of starter motor dashpot with labels] Labels: Hole drilled or pipe to bearings. Lubricating pipe. Steel carcase. Do not forget that I have asked for the motor brushes to create less friction by using brushes with less copper and more graphite. I do not think we should reduce the brush pressure. It would be quite easy to take the fall of potential with the motor stalled and running with say 100 amps, and send me a print shewing where the volts are lost. The object of keeping this friction low is first that it shall not prevent the motor returning, and also to avoid this friction reducing the energy of the engagement. I feel that the best of shapes for the engaging teeth is the engaging corners sharp, and the over-running disengaging corners rounded, thus - (overleaf) (1) | ||