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 improvements for the No. 2 Sequence Starter Motor, including winding, armature size, and efficiency.
| Identifier | WestWitteringFiles\Q\April1927-June1927\ 110 | |
| Date | 8th June 1927 | |
| TO EFC.) FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair}) Copy to Mr Wormald ORIGINAL re. SEQUENCE STARTER MOTOR - No.2. SCHEME. RECEIVED JUN 10 Thanks for your suggested winding for the above. It has occurred to me that you might like to lengthen the armature somewhat in the iron core. Any? I believe that this is a new sized machine that we have not yet put into standardisation, and the point is that your figures suggest the efficiency will be so low that it will take a large current to turn the engine at a reasonable speed. There are two ways of increasing the efficiency, both of which are based upon a larger machine. We have little doubt that we could add say 1/4" to the dia. of the carcase, which might allow .150 on the dia. of the armature, and a slight increase in length. ? It is probable that the 41 slot armature (which is considerably more than the Bosch) with an increase in size might make the most efficient machine, and the most silent, and it might be advisable to scale the present machine up, keeping the 41 sections. I am aware that silence is less important in the starter motor than in a dynamo, but we shall try to get the gearing really good so that any unnec- essary noise from the motor armature teeth is undesirable. Please find out if there is any advantage in the 5" outside of motor carcase. Would 5 1/2" or 5 3/4" dia. be equally convenient from a production point of view - (BY.{R.W. Bailey - Chief Engineer} will know.) R.{Sir Henry Royce} | ||