RU1815710C - Brush-and-collector unit - Google Patents

Abstract

Usage: electric cars, mainly aircraft. SUMMARY OF THE INVENTION: A brush-collector assembly comprises a collector on which diametrically oppositely arranged brush holders with different-polar current collector brushes are mounted. New in the brush-collector assembly is the presence of additional process lubricating non-conductive molybdenum disulfide brushes and a non-conductive binder, installed in additional non-current brush holders on each collector path. Technological lubrication brushes are located between bipolar current collector brushes and are spring loaded. The length of the process lubricating brush is equal to the length of the current brush, and the width is greater than the thickness of the insulation between the collector plates. 3 ill. ate with

Description

The invention relates to electrical engineering, in particular to constructions of a brush-collector assembly of electrical machines, primarily aircraft.

It is an object of the invention to reduce wear on slip rings and additional brushes by forming a specific varnish film including molybdenum disulfide on the collector.

In FIG. 1 shows a general view of a brush-collector assembly; in FIG. 2 - brush holder with a group of collector brushes; in FIG. 3 - brush holder with additional brushes.

The brush-collector assembly contains a collector 1, on which diametrically opposite brush holders 2 with different-polarity current collector brushes 3 and brush holders 4 with additional brushes 5, made of a mixture of molybdenum disulfide 80-95% and non-conductive binder, up to 100% are installed mass of the mixture.

Additional brushes 5 are installed in brush holders 4 on each track of collector 1. The number of additional brushes 5 on the track of the collector is determined from the condition of obtaining minimal wear on collector and additional brushes.

The length of each additional brush 5 IT is equal to the length of the collector brush 3, and the width (bm in Fig. 1) of the additional brush 5 is chosen greater than the thickness of the insulation (bf in Fig. 1) between the collector plates.

Additional brushes 5 are spring-loaded with a force that ensures minimal wear of the additional brushes 5 and collector brushes 3.

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Additional brushes 5 are installed between the collector brushes 3 of different polarities. The installation location of the additional brush 5 is selected taking into account the smallest effect of sparking under the collector brushes 3 on the additional brushes 5. For example, in reversible electric machines with the same level of sparking on the anode and cathode polarized current collector brushes, additional brushes are installed at the same distance from different rtnokotemnyh brushes. In non-reversible electric machines, in the absence of sparking on the running edge of the current collection brush, additional brushes can be installed in close proximity to the running edge of the current collection brush.

The operation of the brush collector assembly is as follows.

When the collector 1 is rotated, additional brushes 5 made of a mixture based on molybdenum disulfide constantly lubricate the surface of the collector 2, along which the collector brushes 3 slide. A specific polyturn film containing molybdenum disulfide is formed on the surface of the collector 1, thereby reducing friction coefficient contact pair of the collector brush - collector, since the additional brushes 5 are non-conductive, they do not close the collector plates and there is no sparking under them, which eliminates the possibility of v reducing lubricating properties of molybdenum disulfide under high temperatures, due to sparking. Non-conductive additional brushes that do not close the collector plates during operation of the electric machine do not cause a decrease in the EMF of the parallel branches of the core winding and distortion of the operating characteristics of the electric machine.

The object of the invention is implemented on a special serial electric machine of low power tight design (6 W), in which between the main brush holders with different polarity collector brushes there is a currentless brush holder with an additional brush made from a mixture of molybdenum disulphide and LBS-5 bakelite varnish, which allows additional brushes withstand operating temperatures up to 200 ° C and does not emit volatile substances when heated, accelerating the wear of current collection brushes in airtight machines.

The length of the additional brush is chosen equal to the length of the collector brush to ensure uniform lubrication of the collector over the entire width of the working path, determined by the axial length of the collector brush and thereby achieve the same wear of the collector and collector brushes along the width of the sliding surface.

The width of the extra brush is chosen to be greater than the thickness of the insulation between the collector plates to avoid

the possibility of trapping an additional brush in the interlamella space. In this case, the width of the additional brush is equal to the width of the collector brush in connection with the use of a serial brush holder for its installation.

The specific pressure on the additional brush is selected from the condition of obtaining the same (in height) wear of the current collection and additional brushes.

0 G21A brushes were used as current collection brushes. The wear of the brushes is determined under normal conditions for 150 cycles of operation of the engine, in climatic conditions when operating for 50 cycles, the pressure on

5 collector brushes equal to 80 g, pressure on additional brushes - 70 g.

Test data are set forth in the table.

From the above data, it follows that the installation of an additional brush on the work path made it possible to reduce the wear of the collector brushes under all operating conditions of the tested motor.

The greatest effect of the use of non-conductive additional brushes based on molybdenum disulfide is obtained when they are operated in vacuum at positive or negative temperatures, depending on the brand of current-collecting brushes.

0 The use of a brush-collector assembly in comparison with the prototype allows to reduce the wear of the current collection and additional brushes due to the formation of a specific polishing film on the collector,

5 including molybdenum disulfide and thus increase the life of the electric machine.

Claims (1)

SUMMARY OF THE INVENTION A brush-brush assembly of an electric machine comprising a collector, multi-current collector brushes installed in diametrically opposite brush holders and additional brushes, characterized in that, for the purpose of 5 to reduce wear on the collector and additional brushes, additional brushes are installed spring-loaded in additionally inserted brush holders between different-polarity collector brushes on each collector track, the length of each the extra brush is equal to the length of the current-made of a mixture containing a discontinuous brush, and the width selected is more than 80-95% molybdenum molybdenum and a non-conductive insulation thickness between the collector binder - the rest is up to 100% of plates, with additional brushes. mixture weight Fig.Z