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 choices for a sequence starter motor, including gear ratio and armature specifications.
| Identifier | WestWitteringFiles\Q\April1927-June1927\ 116 | |
| Date | 11th June 1927 | |
| TO EFC. FROM R.{Sir Henry Royce} ORIGINAL R1/M11.6.27 X7625B SEQUENCE STARTER. No.2B.Scheme. I have decided that this shall push out instead of draw in, and the design we have settled upon permits of a 16 to 1 gear instead of about 13 to 1. This would appear to make calculations much easier, and so improve the efficiency. I should prefer the strip wound armature with one turn per section, the number of sections being from between 40 and 50. Naturally we should prefer to use plates with stamped grooves. These can now be made so accurately even though a large number of slots. The scheme we have made for the design seems much better than our previous one, and we shall avoid the spring pressure rising so high because we intend to let the contact points fall into contact by spring pressure when the armature shaft is out of the way. This will avoid the armature end pull rising for this purpose. I am proposing that the armature shall finish level with the pole pieces, and that the armature core shall be ground taper on the outside. I do not propose altering the dia. of the carcase, and the shaft dia. will be just about .8. I would like you to send as quickly as possible the starter motor we have made, and also the Bosch starter motor, for comparison. [Handwritten note] Plates if stamped, grooves naturally must be parallel. if milled then taper & follow outside R.{Sir Henry Royce} YHR | ||