GB397279A - Improvements relating to the production of alternating modulated, signal tone or like currents - Google Patents

Abstract

397,279. Inductor alternators. JONES, W. and MOLE, F. H., Charlton Works, Newlands Park, Sydenham, London. June 30, 1932, No. 18547. [Class 35.] Machines with two or more armatures.-An alternator producing currents of different frequencies for giving several sound tones, comprises inductor alternator sections with rotors mounted on a common shaft, one or more sections being excited by an alternating-current of a lower frequency and one or more by continuous-current or a permanent magnet, the output from each section being supplied to the appropriate sound tone circuit. The sections A, C supplying telephone signal tone currents of frequency 400 and 33 for the " Busy " and " Dial " tones are excited by continuouscurrent and the section B supplying current at a frequency of 133 modulated to 16.6 for the " Ringing " tone is excited by a current of 16.6 cycles obtained from a separate source or from a rotary transformer or converter E which serves also as the driving motor. The section giving the modulated current may have both continuous and alternating-current excitation or alternating-currents of different frequencies may be used simultaneously.