GB861474A - Photo-electric angular position indicator for balancing machines for rotating bodies - Google Patents

Abstract

861,474. Photoelectric rotational balance indicators. AVERY Ltd., W. & T. Aug. 10, 1957, No. 25308/57. Class 40(3) In a photo-electric angular position indicator employing a wattmeter or wattmeters, for measuring the unbalance of rotary bodies, a polarity reversing device controlled by photoelectric pulses produced by a narrow mark on the periphery of the rotary body is connected in circuit with a condenser to produce across the condenser a triangular waveform at half the rotational frequency of the rotary body, the triangular waveform being applied to a frequency doubling circuit and then to voltage dependent resistances to produce a sinusoidal waveform for the reference phase of the wattmeter or wattmeters. A relatively narrow mark 5, Fig. 1, on the periphery of a rotor 2 produces electric pulses in a photoelectric scanning device 4, the pulses being used to control a polarity reversing device 7 in the supply circuit of a condenser 8 so that the triangular waveform shown in Fig. 4 appears across the condenser. The alternating component of the triangular waveform of Fig. 4 is separated by a condenser inductance circuit 9 and is rectified in a dry rectifier 10. The output of the rectifier 10 is applied to a further condenser inductance circuit 11 which separates the alternating component to produce the triangular waveform of Fig. 7 which is of twice the frequency of the waveform shown in Fig. 4. The output of the circuit 11 is applied to an arrangement of voltage dependent resistances 12 which convert the signal to the sinusoidal form shown in Fig. 8, which is applied to the coil of the wattmeter measuring system for comparison with an unbalance component voltage in known manner.