SU29046A1 - Electric vibrometer - Google Patents

Description

The invention relates to SAiektpHHe vibrometers equipped with an inert mass connected to the instrument body by means of springs. In the proposed vibrometer, in order to register the vibrations of the test body, the inert mass is provided with ferromagnetic plastics placed opposite the coils with closed core mounted on the instrument body, on} Chéneny in the shoulders of the Wheatstone bridge.,

In FIG. 1 shows the mechanical part of an electric vibrometer in a longitudinal section; FIG. 2 is a section along AB in FIG. 1 and FIG. 3 is a diagram of the electronic () part of the vibrometer.

An electric vibrometer consists of a metal plug mounted on a vibrating part of a machine or structure of an inert mass 7 in the form of a polygonal parallelepiped of metal with a large specific gravity (for example, lead) suspended by spiral springs 3 to the body of the device.

The springs 3 in one end are attached to the four parallel body of the device, the ribs of mass 2, and the others to the four parallel edges of the body 2. The elasticity of the spring is chosen so that the period of its own

load oscillations in the vertical and horizontal directions would be significantly lower than the lowest frequency of the vibrations to be measured.

Under these conditions, despite the oscillations of the instrument case together with the machine or structure part being examined, the seismically suspended mass will remain at rest and will represent that relatively fixed base relative to which the amplitudes of the vertical and horizontal oscillations of the case and hence the part of the machine or structure under investigation.

The upper and one of the side walls of the housing 2, which are perpendicular to the plane of location of the springs 3, are reinforced inside the housing with flat springs and U-shaped parts of jet coils 4, 4 to 5, 5, two pieces on each wall. On the opposite inertial mass walls / ferromagnetic plates 8 are fixed. The air gaps between the U-shaped parts of the coils and the plates, and hence the coefficients of the self-inductive coils, can be adjusted by screws 7 passing through the walls of the housing 2.

The electric part of the vibrometer (Fig. 3) consists of a Wheatstone bridge operating on alternating current, the shoulders of which include reactive coils 10, W and 4, 4, or 5, 5 with herbal resistances mI and at a constant vibrometer body and with equal coefficients of self-induction. Two of these coils 70 and, / (included in the cross-shouldered shoulders of the Wheatstone bridge are coils with the same and constant self-induction coefficients.

The other two pairs of coils -i, 4 and 5, 5, mounted in the vibrometer box, during its operation (body oscillations represent coils with a variable self-induction coefficient, due to varying air gaps. By means of a switch, these coils can be in pairs 4 and 4 or 5 and 5 are inserted into the other two crosswise-lying shoulders of the bridge. Coils 4 and 4, mounted on the upper wall of the instrument, serve to measure the amplitudes of vertical oscillations, and mounted on the side wall, to measure horizontal oscillations. The bridge diagonals switch on the measuring device / 2 with any rectifier 7 7. The scale of the device 72 is graduated in units of lgm. The alternating current source is switched on to another diagonal. Before starting the readings in the quiescent state of the vibrometer, set screws. coils 4, 4 and 5, 5 can be adjusted so that the equilibrium state of the bridge sets in, which is characterized by the position of the arrow of the measuring device 72.

Due to the introduction of coils with variables of the same nature and

the magnitude of the change, the coefficients of self-induction in the two nakri of the bridge's shoulders, achieve a much greater sensitivity of the vibrometer than in the presence of a coil with a variable coefficient of self-induction only in one of the four shoulders of the bridge.

Increasing the oscillation amplitude measurement limit is produced by the adventure of a shunt to a thermal vacuum element or other rectifier.

The subject matter of the invention.

1. An electric vibration meter provided with an inert mass connected to the instrument case by means of springs, characterized in that in order to record the vibrations of the test body, the inert tube 7 is provided on two mutually perpendicular walls with ferromagnetic plates 8 located opposite the reactive coils 4 mounted on the instrument body 4 4, 5 and 5 with an open core included in the shoulders of a Wheatstone bridge powered by alternating current .2. When using a vibrometer according to claim 1, use screws y. QTaHOBO4Hbir that go outside through the instrument and configured to adjust the size of the air gaps between the jet coils and the plates 8, by pressing them onto the supporting jet coils of the spring 6.,

3.When vibrometer according to claims 1 and 2, use two reactive coils 10 and 7 (7 with identical and constant self-induction coefficients included in the opposite shoulders of the bridge in order to increase the sensitivity of the device.

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