Remote control receiver for central remote control installations utilising audio-frequency signals superimposed on the mains network

摘要

820,141. Electric selective signalling. LANDIS & GYR A.G. Aug. 1, 1957 [Sept. 27, 1956], No. 24469/57. Class 40 (1). A receiver for a remote control system of the kind using audio-frequency signals superimposed on the mains network Q has a synchronously-moving selector switch arm w, Fig. 2, a relay R energized by the incoming control pulses through a frequency-responsive circuit EK and, in series with the contact r of this relay, a controlled auxiliary contact h which makes after and breaks before the contact r so as to protect the latter against undue wear. The switch arm w is driven by a synchronous motor Sy which is started by a start pulse ST, Fig. 1. Subsequent pulses B in the cycle cause contact r to close while the arm w is in contact with corresponding studs S to energize relay coils K 3 , K 4 , &c. These coils are arranged in pairs and displace switches k 3 , k 4 , &c. to alternative positions. The auxiliary contact h, which may be much more robust than contact r, is driven by a cam from the synchronous motor Sy and closes for short periods th shown in line D 3 . The switch arm makes contact for periods t w shown in line D 2 . The load current is therefore switched on and off by contact h, the length of life of contact r being increased accordingly. In the form of Fig. 5, the auxiliary contact h is replaced by contacts h 3 , h 4 , &c., in the circuit of each control coil K 3 , K 4 which are single-coil change-over relays. The contacts h 3 , h 4 transfer when the coils K 3 , K 4 are energized and make contact with the alternative stud, thereby interrupting the coil current. The current is therefore switched on by the relay contact r (which is the less damaging of the two operations) and is switched off by the relay contacts h 3 , h 4 , &c. Furthermore, on repetitive orders, occurring in subsequent cycles, there is now no circuit through the coils K 3 , K 4 , &c. so that no current passes when the contact r makes.