GB925576A - Warning apparatus - Google Patents

Abstract

925,576. Measuring electrically. LEAR Inc. May 1, 1961 [May 11, 1960], No. 15620/61. Class 40 (1). In a selsyn system wherein the receiver rotor 24 (Fig. 1) is driven to a null position by a servomotor 28, an additional perpendicular rotor winding 22 is simultaneously driven to its maximum voltage position, and the voltages on the two rotors 22, 24 are compared via rectifier bridges 30, 32 to operate an alarm 36 when the voltage in 22 decreases, or the voltage in 24 increases. In an embodiment for comparing the readings of three flux valve compasses 40a, 40b, 40c (Fig. 2), the magnetic field distribution is transferred to a selsyn 48 to produce an error signal in winding 52 which is amplified at 54 to control a torquing device 56 on the leveling axis of a gyroscope 58, causing it to precess about its azimuth axis, by an angle which is transmitted by selsyn 60 to selsyn 62, the voltage in rotor 66 being fed to motor 70 which drives the rotor 66 to its null position, thereby producing on the compass card an indication of the heading of the supporting vehicle. The angular position of motor 70a is compared with that of 70b by selsyn link 72a, 88. If the two angular positions agree, perpendicular rotors 92, 94 have maximum and minimum voltages induced in them, and any deviation from this condition produces an alarm indication. Similarly, the angular positions of motors 70c, 70b are compared by selsyn link 72c, 80 and produces an alarm indication when they do not agree.