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The positive results of works of the electric brushes were obtained with upgraded polymer overlays NK-8

polymer overlays NK-8Dumper rubberized overlays NK-8 had successfully tested on Zmiev HES. Undoubted effect were marked at reduction of vibrations in compared with metal overlays NK-1 and NK-2.

Date: 21.08.2018

Specialists of the company LEG Ltd. have developed a brush holder with a roll constant-pressure spring

Brush holder with a roll constant-pressure spring

Specialists of the company LEG Ltd. have developed a brush holder (see fig.) with a roll of constant-pressure, which helps to prolong the сommutator and the brush service life; excludes the «human factor»; allows to install a brush with a large radial size (up to 80 mm); provides a uniform constant pressure on the brush. The figure shows a brush with a shock-absorbing polymeric plate NK-8. The plate is unified and allows to install the brush both in a traditional brush holder, including the one with collet gripping unit, and in the brush holder with the roll constant-pressure spring.

There is a vertical groove in the brush box, which allows visual wear monitoring, and if there is a retainer on the plate NK-8 (in the figure), it limits the ultimate wear of the brush.

 

Date: 07.08.2018

A new type of overlays NК-8 is developed

Overlays NK-8A new type of overlays NК-8 is worked out and is undergoing tests now. In case of positive test results it is supposed to replace metallic overlays NК-1, NК-2 and rubber overlays NК-6, NК-7 with these ones at all types of carbon brushes execution.

Date: 20.07.2018

Specialists of the company LEG Ltd. have developed and put into production new carbon brush materials - EF-68 and FE6X.

Carbon brushes from the new graphite-polymeric materials EF-68 and FE6X have high physico-mechanical and collector characteristics. The materials passed a full cycle of bench tests at the certified center of the SE Plant Electrotyazhmash. The above-mentioned materials are characterized by: low wear, reduced coefficient of friction (0.13-0.16) when the total voltage on a pair of brushes drops to 1.6-3.2 V and a uniform brush film, which is fast formed.

A key feature of these materials is that they work instead of several completely different classes of brush materials: EG61A, G-27, MGS8. This list is by no means exhaustive.

 

Date: 01.02.2017 details

We offer you to read our thought on the determination of the optimum sliding electric contact operating conditions based on minimum energy release conditions

Determination of the optimum sliding electric contact operating conditions based on minimum energy release conditions

A huge amount of research has been devoted to issues related to optimum working conditions of sliding electric contacts (e.g. carbon brushes). A considerable number of theories, has been put forward, more or less successfully describing some individual cases. Every self-respecting manufacturer (and we are no exception) shall certainly indicate the operating conditions of all own brands of carbon brush materials which he sees optimal.All the brochures dedicated to carbon brushes by all means specify the maximum permissible collector linear speed, the suggested brush pressure, normal current density, the coefficient of friction and contact voltage drop across a pair of brushes. All manufacturers of electric machines consider themselves to know the optimum collector temperature and a lot of other sliding contact parameters. However, up to now the trial and error method has been the only way to select carbon brushes for a newly created machine.

Date: 15.12.2016 details