A New Frequency Selective Vibrometer

Abstract

This paper gives the theory and practice involved in the design of a small instrument which is useful in measuring the frequency, direction, and amplitude of vibration. The instrument obtains its frequency selectivity and high sensitivity by mechanical resonance. A novel method of tuning is employed which also produces variable damping in such a manner as to produce an essentially flat frequency response. The direct indicating model shown in the accompanying photographs covers an amplitude range up to 0.010″ double amplitude and a frequency range from 800 c.p.m. to 2000 c.p.m. Other ranges have been covered by other models and models have been produced using a photoelectric pick-up which made it possible to read the vibration amplitude on a meter with greater precision than on the direct indicating model.