GB1279840A - Synchro indicating system - Google Patents

Abstract

1279840 Synchro indicating systems BENDIX CORP 12 Dec 1969 [19 Dec 1968 (2)] 60643/69 Heading G1N A synchro indicating system comprises an A.C. synchro transmitter and a D.C. synchro receiver wherein polyphase stator windings of the two synchros are inter-connected through phase controlled rectifier units which each include a pair of transistors. As shown an A. C. synchro 5 comprises a rotor 25 and a stator with 3 windings 28, 29, 30, each connected to a corresponding winding 50, 51, 52 of a D. C. synchro 15 with a permanent magnet rotor 55 controlling one digit of a numerical indicator. The connections are made through phase-controlled rectifiers 10, 10A, 10B each of which comprises a pair of back-to-back NPN transistors 37, 42 controlled through windings 13, 14. These are supplied with supply alternating current biasing a phase relationship with the supply E 1 at 11 as indicated by the dots. Assuming the rotor 25 to be in a position that the L.H.S. of E 2 is positive when the dotted ends are positive then during positive half cycles transistors 42 and 37A conduct and during negative half cycles all transistors are back biased off causing half-wave rectified signals with the polarity shown on the stator windings of syncro 15. If the rotor position is such that the R.H.S. of E 2 is positive when the dots are positive the polarity applied to the stator windings is reversed. Similar argument applies to the voltages E 3 and E 4 and the resultant as applied to the rotor 55 corresponds with the applied position of the transmitter rotor. Similar arrangement may be utilized to control two further indicators Fig. 1 (not shown). A further arrangement, Figs. 3 and 4 (not shown) utilizes phase-controlled rectifiers in only two of the three phase-to-phase stator-connecting lines. In this case each phase-controlled rectifier comprises a PNP and an NPN transistor in parallel.