Abstract
In stroboscopic measurement of rotational speed, the observed pattern is stationary at everyrotational speed which is multiple of primary speed. Since suitable multiple measuring method hasnot been known, there has been serious troubles in measuring. On the other hand, suitable measuring device is useful not only for removing such troubles but for extending measurable speedrange of the stroboscope.
In this paper two practical methods, method 1 and method 2 are discussed. Operating principlesof these methods are quite different from each other; the former makes use of mathematical natureof series of flush frequency when single stationary pattern appears, but the latter makes use of therelation between the phase difference of two flushes with equal frequency, and the angular differenceof double stationary patterns.
Biased multivibrators modified for the above two methods are presented, and satisfactory result hasbeen obtained. The electronic circuit for method 2 is a little more complicated than that for method 1, but it was proved by experiments that the former is much more convenient for mesuring operation.
