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).
Proposal for a modified engagement method for the Spectre starter motor, outlining the disadvantages of the current system.
| Identifier | ExFiles\Box 62\1\ scan0294 | |
| Date | 7th February 1935 | |
| E.{Mr Elliott - Chief Engineer} From Hs{Lord Ernest Hives - Chair}/Wat. c. to SE. c. to Wor.{Arthur Wormald - General Works Manager} c. to Ey. c. to Mx.{John H Maddocks - Chief Proving Officer} c. to EP.{G. Eric Platford - Chief Quality Engineer} MODIFIED METHOD OF ENGAGEMENT FOR SPECTRECodename for Phantom III STARTER MOTOR. The sequence starter motor has several in-herent disadvantages which can be briefly summarised as follows :- (1) The presence of an auxiliary field winding limits the available torque on the motor for a given size. (2) The movement of the heavy armature with the pinion necessitates fairly excessive engaging forces and requires the use of a damper to absorb the shock in and out of gear. (3) The movement of the armature longitudinally necessitates long plain bearings and a commutator double the ordinary length. A new method is proposed in which the slow engagement features of the present sequence starter scheme are retained without the disadvantages outlined above. A brief description of this new scheme is as follows :- (a) The auxiliary (teazer) winding is eliminated and the armature increased in diameter with reduced length field pole cores to give increased torque. The field winding is thus simplified and the motor only requires one terminal instead of three as at present. (b) The armature remains stationary and the whole motor is therefore shortened approximately by the length of the existing travel, i.e. .75 inches. The armature shaft can also be mounted on ball bearings. | ||