SU756529A1 - Inductive meter of electric machine brush wearout - Google Patents

Description

The invention relates to electrical engineering.

A tool for measuring the wear of brushes is known. As a magnetically sensitive element, a rod is used that interacts with the cat. Such konsTg operation, having high reliability, greatly increases the overall dimensions of the brush unit.

Also known is a contactless gauge for the position of the brush of an electric machine located in the holder of the brush holder, which contains a magnetic element in the form of a magnetic circuit, which is fixed in the active body of the brush, a magnetic sensitive element in the form of an inductive coil connected through a measuring device to the measuring device.

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However, the reading of the instrument indicating the wear of the brush in the known device is influenced by the alternating air gap between the magnetosignal and magnetically sensitive elements (between the brush and the wall of the holder of the brush holder) arising during operation.

The purpose of the invention is to eliminate the influence of the variable air gap between the brush and the walls of the holder of the brush holder on the readings of the measuring device.

15 This is achieved by the fact that in the proposed device, the magnetosignal element is O-shaped, the magnetosensitive element is located on the holder of the brush holder and covers it, and the plane of the turns of the inductive coil is perpendicular to the longitudinal axis of the holder of the brush holder.

FIG. 1 shows an inductive brush wear meter of an electric machine; in fig. 2 - mutual arrangement of the coil and the 0-shaped magnetic circuit with a non-brush; in fig. 3 - relative position

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756529

magnetic conductor and coil with a worn brush.

The converter for moving the brush into an electrical signal is made in the form of a magnetically sensitive element of an inductive coil 1 (see Fig. 1), covering the holder of the brush holder 2, and a magnetic signal element - O-shaped magnetic circuit 3. The magnetosignal element is located in the active body of the brush 4. Coil 1 is connected via converter 5 to power supply 6 and measuring device 7. For example, a high-frequency voltage source can be used as a power supply, and a filter that cleans the useful signal from components can be used as a power supply. EMF induced by the movement of the brush, caused, for example, protruding insulation of the collector, the deviation of the shape of the collector ring from the circle.

The operation of the device is based on the measurement of an electrical signal due to a change in the flux linkage of the magnetically sensitive element. The latter, in turn, is due to a change in the relative position of the magnetosignal and magnetically sensitive elements.

The meter works as follows ..

When the coil 1 is connected to the power source 6, the coil creates a magnetic flux Φ, which closes along the paths shown in the drawing by dashed lines. The magnitude of the magnetic flux is determined by the MDS of the coil.1 and the total magnetic resistance of the paths of propagation of the flow and, to a large extent, by the relative location of the magnetic core 3 and the coil 1 of the magnetically sensitive element. In turn, the latter determines the resistance of the coil 1 and the magnitude of the current in the value of the measuring device 7. The arrow in FIG. 2 shows the spring force acting on the brush. By

to the extent of the development of the brush at. friction on the collector 0-shaped magnetic core moves with the brush. From a comparison of the patterns of propagation of magnetic fluxes Φ, it follows that the flow of coil coupling changes as the brush is produced.

Thus, the device allows to determine any position (or development) of the brush from the initial one, when a new brush is installed, to the final one, corresponding to its maximum development. In this case, no adjustment of the relative position of the brush and the magneto-signal element is not required when replacing the brush, since the magneto-signal element is located in the brush. The adjustment of the current value corresponding to the initial position of the brush, due to the natural variation of the brush dimensions when it is manufactured, can be easily carried out with the help of a resistor placed, for example, in a measuring device.

The technical and economic effect is ensured by the fact that with a more accurate measurement of the wear of the brushes of an electric machine, the operating costs associated with the premature replacement of brushes are reduced. In addition, when servicing aircraft electrical equipment, due to the technical condition, the level of flight safety increases, since an increase in the reliability of the gauge allows a more reliable prediction of the behavior of the brush-collector unit of the electric machine.

Claims (1)

Claim An inductive wear meter for the brush of an electric machine located in the holder of the brush holder containing a magnetic element in the form of a magnetic circuit that is fixed in the body of the brush, a magnetic sensitive element in the form of an inductive coil connected through a converter to the measuring device, characterized in that the gap between the brush and the walls of the yoke. brush holder on the readings of the measuring device, the magneto-signal element is made 0-shaped, magnetically The tangent element is located on the holder of the brush holder and covers it, and the plane of the coils of the inductive coil is located perpendicular to the longitudinal axis of the holder of the brush holder. 756529 fig.Z