GB966766A - An arrangement for providing a measure of the magnet wheel angle of a synchronous generator - Google Patents

Abstract

966,766. Testing synchronous generators; photo-electric systems. SIEMENS-SCHUCKERTWERKE A.G. Feb. 20, 1961 [Feb. 20, 1960], No. 6237/61. Addition to 937, 462. Headings G1A and G1U. [Also in Division H3] In an arrangement according to the parent Specification for providing a measure of the magnet wheel angle of a synchronous generator, square waves are generated corresponding in phase to the alternating output voltage of the generator and to the magnet wheel vector, and these two square waves are used together to produce an output signal consisting of a series of rectangular voltage pulses of constant amplitude, the duration of each pulse being directly proportional to the magnet wheel angle. According to the present invention these pulses are fed to two transmission channels 2 and 4, one of which includes a monostable switching device 5, which lead to a logical gating arrangement giving an output comprising a series of rectangular voltage impulses whose direct current mean value is substantially a broken linear function (Fig. 1), in which no output is obtained until a lower threshold value of the magnet wheel angle is reached and in which the output is limited in amplitude above a second angle value. In one embodiment (Fig. 2) the output from the monostable device 5 is inverted before being combined with the input signal to the whole arrangement in the AND gate 3. This gate will therefore only pass a signal after the pulse from the monostable 5 has finished. The output from the gate 3 triggers the monostable 10 whose output is passed directly to the AND gate 8 together with the output from the gate 3. The gate 8 therefore gives a pulse output whose width is the same as that from the gate 3 provided this does not exceed the width of the pulse from the monostable 10. The monostable 5 therefore determines the lower threshold angle and the monostable 10 determines the range of angles over which a linear output is obtained. The broken linear function is especially suitable in some forms of retroactive control. By a suitable rearrangement of parts (Fig. 3) only one AND gate 12 is required.