GB313524A - Improvements in synchronous electric motor systems - Google Patents

Abstract

313,524. Karolus, A. June 13, 1928, [Convention date]. Frequency, changing. - Synchronous electric motors suitable for television and other apparatus are fed from mains of low frequency transformed or tuned up to higher harmonic frequencies, and are used either as driving motors of the apparatus or as auxiliary synchronous motors coupled to main driving-motors. In one arrangement an alternating current network 1 supplies a 50-cycle current to a main motor 5, and current of tuned-up frequency to a synchronous motor 10. A frequency transformer 6, 8 has a variable resistance 7 to vary the current through the primary winding 6, the secondary winding 8 being tuned with the inductance of the motor 10 and the variable capacity 9 to a higher harmonic of the feed system e.g. 500 cycles. The picture transmission apparatus 11 is connected to the common shaft of the motors 5, 10, and motor 5 maintains synchronism with motors similarly fed by the circuit 1. The frequency transformation may be obtained by other means such as by the use of glow or arc discharge tubes. Rectification may be used to obtain frequency duplication.