GB391565A - Improvements in or relating to synchronous electric motors - Google Patents

Abstract

391,565. Motors. TELEPHONE MANUFACTURING CO., Ltd., Hollingsworth Works, Martell Road, West Dulwich, London, and BURRIDGE, B. J., 1, Banstead Way, Wallington, Surrey. Feb. 6, 1932, No. 3600. [Class 35.] Motors with unwound iron armatures; driving arrangements.-In a synchronous motor for clock driving &c. of the type comprising a stator having a number of teeth which at any instant will all be of the same polarity, a toothed rotor and a stator core coaxial with the stator and rotor, the stator core has a length substantially equal to or greater than the axial length of the exciting winding to which the alternating current is supplied and the rotor is pivotally mounted in or on the end of the stator core or a part attached thereto. The stator structure comprises a central core 11 carrying the winding 14 and side arms 10 secured by a nut 12 to the end of the core and terminating in an internally toothed ring 16. The soft iron disc rotor 28 is mounted in a non-magnetic bush 23 on a spindle 20 journalled in a non- magnetic bushing 21 recessed into the enlarged top of the core 11, the stator and rotor teeth being shaped as shown in Fig. 2. The object of the bushes 21, 23 is to reduce saturation at the centre of the rotor disc. A flywheel 25 is loosely connected to the rotor spindle 20 by rod 26 fixed in the flywheel and passing through a hole of larger diameter in the spindle and the motor is started by giving the rotor an impulse.