Study on surface film in the wear of electrographite brushes against copper commutators for variable current and humidity

Hu, Zhaoyang; Chen, Z.H.; Xia, Jintong

doi:10.1016/j.wear.2007.01.034

Cited by 74 publications

(43 citation statements)

References 23 publications

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“…There are several different phenomena (electrical, tribological and chemical) (Yoichi et al 2002;Yasar et al 2007;Hershberger et al 2004;McKee et al 1972) which can play a role in the degradation of the C/C materials. Although there are works about motors working in air (Robert et al 1995;Hu et al 2008) the studies concerning motors immersed in organic liquids are almost inexistent (Yamamoto et al 1995). In the aim of understanding the specific interaction between carbon materials and bio-fuels, the adsorption of oxygenated hydrocarbons (ethanol) from a pure organic mixture on carbon was performed in this work.…”

Section: Introductionmentioning

confidence: 99%

A TPD-MS study of the adsorption of ethanol/cyclohexane mixture on activated carbons

et al. 2011

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The adsorption of ethanol/cyclohexane binary mixtures on different types of activated carbons was studied in this work by temperature programmed desorption coupled with mass spectroscopy (TPD-MS). The texture, morphology and surface chemistry of the carbons were evaluated by N 2 adsorption, scanning electron microscopy (SEM) and TPD-MS techniques. The ethanol and cyclohexane TPD-MS desorption profiles showed that specific interactions between the carbon material and the adsorbate are involved during the adsorption. Most of the activated carbons adsorb strongly ethanol on the surface, leading to desorption temperatures above 100°C. Only one carbon exhibits an affinity for cyclohexane. These observations were correlated to the different surface chemistry of the materials.

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Section: Introductionmentioning

confidence: 99%

A TPD-MS study of the adsorption of ethanol/cyclohexane mixture on activated carbons

et al. 2011

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“…Much research has been conducted to investigate the effects of contact voltage drop, surface temperature of brushes, coefficient of friction, normal load, sliding speed, current density, and others as shown in Fig. 1 [8]. In this research, the main influencing factors for brush wear are studied through the contact between brush and commutator.…”

Section: Introductionmentioning

confidence: 99%

An analysis of the main factors on the wear of brushes for automotive small brush-type DC motor

Shin

Lee

2010

J Mech Sci Technol

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Some critical components in motors and generators have sliding electrical contacts. Electrical brushes are commonly used in those contact points to conduct current between the stationary and moving parts of a motor. Brushes are exposed both to mechanical and electrical loading. In this paper, studies on the wear of brushes against copper commutator were briefly reviewed. The main influential factors of brush wear are associated with both mechanical and electrical wear. Brush wear is affected by various factors including temperature, material properties, sliding speed, contact force, and interfacial and environmental conditions. The mechanical wear of brushes is proportional to the brush spring pressure and sliding speed, while the electrical wear of brushes is associated with current and contact voltage drop. To characterize the wear, a brush wear test machine was designed, and influential factors were measured such as electrical contact resistance, temperature, wear mass loss, and so on. The wear tests were processed using a small brush type automotive DC motor.The main objective of this study is to investigate the effects of the wear behavior of copper-graphite brushes in a small brush-type DC motor. The variable conditions are with and without electrical current by changing the brush spring pressure and sliding speed, and the results are electrical contact resistance, voltage drop, brush surface temperature rise, and so on. Brush wear greatly changes with electrical current. This shows that the high current not only produces more Joule heating but also causes an increase in voltage drop, which will result in additional Joule heating.

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“…The average values of mechanical properties such as density and hardness of metal-graphite brush were 2.5 g/cm 3 and 19.0 HsD respectively.…”

Section: Brush Materials and Its Propertiesmentioning

confidence: 99%

Electrical contact resistance and wear of a dynamically excited metal–graphite brush

Turel

Slavič

Boltežar

2017

Advances in Mechanical Engineering

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The wear and contact resistance of sliding contacts are typically researched with a pin-on-disk experiment that prevents dynamic excitation. However, in electrical machines, the brush clearance enables dynamic excitation, resulting in flexible body dynamics. To research the wear and contact resistance during dynamical excitation, an in-situ experimental approach is introduced here, with the influences of rotational speed, electrical current, and temperature being assessed. This research shows that a small wear rate and contact resistance are possible at 10,000 and 5000 RPM if the electrical current is higher than 3 A. It was also found that the contact resistance decreased with an increased ambient temperature, electrical current, and rotating speed, whereas the wear rate increased with the rotating speed at low current density and low ambient temperature.

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Study on surface film in the wear of electrographite brushes against copper commutators for variable current and humidity

Cited by 74 publications

References 23 publications

A TPD-MS study of the adsorption of ethanol/cyclohexane mixture on activated carbons

A TPD-MS study of the adsorption of ethanol/cyclohexane mixture on activated carbons

An analysis of the main factors on the wear of brushes for automotive small brush-type DC motor

Electrical contact resistance and wear of a dynamically excited metal–graphite brush

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