GB896415A - An apparatus for the conversion into two potentials of an alternating current generated by scanning rotating bodies - Google Patents

Abstract

896,415. Measuring dynamic unbalance electrically. AVERY Ltd., W. & T. (Schenck Maschinenfabrik G.m.b.H., Carl). Sept. 23, 1958, No. 30294/58. Class 40 (1). [Also in Groups XL (b) and XL (c)] Apparatus for producing two quadrature sinusoidal voltages synchronous with a rotating shaft, for use in dynamic unbalance measuring systems, comprises a ring 2 (Fig. 1), mounted on the shaft, having half of its surface black and half white, whereby the light from a lamp 1 reflected from its surface to a photo-cell 3 consists of rectangular pulses of equal mark-space ratio, at the correct frequency, which pulses are modified to produce the required quadrature sinusoidal voltages. As shown, the rectangular pulses are fed through a peak limiter 4, an integrator 5 to obtain a triangular waveform, a further integrator 6 to obtain a first substantially sinusoidal waveform, and a third integrator 7 to obtain a second substantially sinusoidal waveform in quadrature with that obtained from the previous stage 6. In another embodiment (Fig. 8), the triangular voltage from 5 is fed to a converter 10 with a non-linear characteristic producing a substantially sinusoidal waveform, and also to a peak limiter 8 giving a trapezoidal waveform, which is integrated at 14 to give a triangular waveform and fed to a second converter 15 similar to 10 to give a second substantially sinusoidal waveform in quadrature with that from converter 10.