SU716094A1 - Device for testing electric machine brushes - Google Patents

Description

one

The invention relates to electrical engineering and relates to devices for testing various current collection stations of electrical machines and their components (brushes, collectors, current collectors, etc.).

Devices for testing electrical machines are known, consisting of an external motor, a collector simulator in the form of a short-circuited ring with brushes mounted on it and connected to the power supply circuit through a rheostat 1.

A disadvantage of such devices is the absence of an arcing factor acting in a real electric machine during switching and having a strong influence on the most important characteristics of a contact pair, including wear.

It is also known a device for testing brushes of electric machines, which is closest to the invention and consists of a drive motor, a collector simulator in the form of a short-circuited ring with brushes mounted on it, connected to the power supply circuit through a rheostat and inductance 2.

This device provides education in the contact zone of the arcing factor, adjustable in power and similar in nature, taking place in a real machine during switching. In this way, wear tests are provided under conditions close to real conditions. However, on this device it is impossible to test the brushes of machines with cyclic current overload. In addition, if it is necessary to increase the pulse current load, the arcing power rises sharply, since it depends on the square of the current, which greatly limits the possibilities of this technical solution and reduces the current overload limits.

5 The aim of the invention is the possibility of conducting tests under cyclic current overloads.

This is achieved by the fact that in a known device containing a drive motor, a collector simulator in the form of a short-circuited ring with insulated inserts, mounted on a brush simulator, connected to the power supply circuit through a rheostat and inductance, the brushes are installed

so that the arc values around the simulator circumference between the edges of each insert (a), the incident edges of the adjacent unipolar brushes (b), the external incident and escaping edges of the adjacent brushes (c) and the corresponding edges of the adjacent inserts (d) c inequalities

a b c d, and a

The drawing schematically shows the proposed device.

Brushes of positive 1 and negative 2 polarities (three unipolar brushes are shown in the drawing) are installed on the collector simulator 3, which is a cylinder of electrically conductive material with insulating inserts 4 on the surface in contact with the brushes. Insulating inserts are made from conventional anti-friction materials, such as PCB. They can also be made of electrically conductive materials, in which case they should be isolated from the conductive component of the simulator, for example, using insulating gaskets. One or several isolating inserts are installed on the simulator, depending on the switching conditions of the simulated electric machine.

The simulator is rotated by a driving motor (not shown).

Unipolar brushes are connected to. power supply through a rheostat R and inductance L and set so that the arc size around the simulator circumference between the edges of each insert (a), the arc size between the incident edges of adjacent unipolar brushes (b), the arc size between the external incident and escape edges of adjacent the same-sex brushes (c) and the arc size between the respective edges of the adjacent inserts (d) are related by the inequality a b c d, with c b. but.

The device works as follows

When the simulator rotates at the moments of brushing away from the brushes conducting to the insulating insert, the accumulated electromagnetic energy is released in the form of arcing. At the same time, the arcing power is regulated regardless of the magnitude of the specified overload currents by varying the current values, the voltage of the power supply, the inductance, the number of insulating inserts, and the frequency of rotation.

716094

Due to the position of the unipolar flower and the insulating inserts in the time when one of the brushes is on the insulating insert, the other brushes (at least one of them) are on the conductive part of the simulator and work with current overload, because they take The load of the insulated brush itself, Thus, each of the brushes, except for the moments of running through the insulating inserts, is cyclically loaded

current of increased magnitude, regardless of the regulation of the power of arcing. The degree of overload is governed by the number of unipolar brushes. With two unipolar brushes overcurrent - 100%

(double load), as the number of unipolar brushes increases, the current overload decreases.

The invention allows testing of brushes at given current overloads: and a given spark power without

use of auxiliary equipment. In this case, the current load limits are cleared to double overload.

Claims (2)

Invention Formula Apparatus for testing brushes of electric machines, containing a drive motor, named after a collector in the form of a short-circuited ring with insulated inserts, mounted on a brush simulator, connected to the power supply circuit through a rheostat and inductance, characterized in cyclic overloads, arcs around the simulator circumference between the edges of each insert (a), the incident edges of the adjacent unipolar brushes (b), the external incident and escape edges of the adjacent x unipolar brushes (s) and the respective edges of the adjacent inserts (d) associated with inequality and L d, and c - b a. Sources of information taken into account in the examination 1. A. Bordachenkov and B. Gnezdilov. The collector-brush assembly of traction electric machines of locomotives. M., “Transport, 1974, p. 92 - 94. 2. USSR author's certificate No. 532923, cl. H 011 43/00, 1975 (prototype).