Transmission system

1,126,064. Control of stepping motors. SPERRY RAND Ltd. 8 June, 1966 [14 June, 1965], No. 25066/65. Heading H2J. A transmitter for high level electrical signals comprises a commutator having contact-sets 3, 4, 5, co-operating with brushes 7, 8, 9, which are separately connected through resistors 10 to the bases of thyristors 11, 12, 13. Coils 15, 16, 17 of a repeater 1 are connected to the thyristors and are energized singly or in pairs to provide a field which causes the rotor of the repeater to move to a position corresponding to the position of rotor 2, the latter being energized through step-down transformer 18. Diodes 19 suppress surge currents, a lamp 22 illuminating the repeater system.