GB1157062A - A Method and Arrangement for Determining the Mechanical State of Machines - Google Patents

Abstract

1,157,062. Testing machines electrically. KONSULTBYRAN IKO A.B. Feb. 23, 1968, No.8831/68. Heading G1N. The output of a vibration pick-up (not shown) is filtered at 200 to pass only those high frequency oscillations which correspond to mechanical transients set up in the pick-up by vibration of a machine under test, the electrical oscillations corresponding to the actual machine vibration not being utilized. The characteristics of the pickup being known, the high frequency output provides a measure of machine vibration and hence of wear. The pick-up output is applied to a filter unit 200, which feeds both a measuring unit 300, which determines the frequency of occurrence of transients above a certain amplitude, and also a second measuring unit 400 which determines the maximum energy content of the transients over a given period. The signal to unit 400 may be passed first through a segregating unit 500 which is synchronized to the machine under test and enables the energy content of transients occurring at a given point at each cycle of operation of the machine to be measured. The transients produced in the output of a Piezo electric pick-up attached to the machine are separated from background vibrations by a filter (204-209, Fig. 2a', not shown) in the unit (200, Figs., 2a<SP>1</SP> and 2a<SP>z</SP>, not shown). The unit (200) also includes differential amplifiers (212, 217, 221, 225, 228 and 250) pulse shapers (218, 251) and integrators (221, 233) for producing, for each transient, a pulse (5, Fig. 2b not shown) with an amplitude proportional to the energy content of the transient (1). The measuring unit (300, Fig. 3a, not shown) includes a monostable (305) and produces a pulse (8, Fig. 3b, not shown) for each energy pulse (5) in excess of a certain level (6), and also an integrater (307, 308) giving an output proportional to the occurrence frequency of the pulses (8). The second measuring unit (400, Fig. 4a not shown) includes an integrator (407, 408) whose output (9, Fig.4b not shown) represents the maximum amplitude of pulses (5) over a period of time controlled by a switch (410). Alternatively the period of time is controlled by the segregating unit (500, Fig. 5a not shown) which receives a synchronizing pulse (13, Fig. 5b not shown) from the machine and generates a sawtooth (14), the period being selected by adjusting (at 510) a voltage (15).