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

Abstract

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.

Compliant mechanosensory composite (CMC): a compliant mechanism with an embedded sensing ability based on electric contact resistance

“…Many previous works have used ECR for sensing in various applications. For example, the ECR between carbon fiber polymer matrix composites [21], steel and cement [22], cement and cement [23], polymer and polymer [24], graphite and graphite [25], metal and metal [26], metal and graphite [27], etc. Owing to the ease of fabrication and integration, the ECR between polymer and polymer is utilized in this work.…”

Wear Rate vs Dynamic and Material Properties at Elevated Temperatures for a Copper-Graphite Brush

“…Strojniški vestnik -Journal of Mechanical Engineering vol(yyyy)no, p-p conditions was reported previously [26]. The 90 tests were conducted for temperatures of the brush between 30 • C and 120 • C. The wear rate of the brush was identified with a camera using a digital image correlation, where the initial s 1 and final s 2 positions of the brush were measured.…”

“…The dynamic properties were investigated through the natural frequencies, the hysteretic damping ratio and evaluated through the material's properties, i.e., hardness tests and DSC, while the wear rate was measured previously, see, e.g., [26].…”

“…They observed that an increase in the copper content in the composite leads to a change in the shape of the TG curves, while the binder properties, an ordinary compound of the brush composite, can be tested with differential scanning calorimetry (DSC) [23]. In addition to the DSC analyses, the material properties were also studied using hardness tests [24].The effect of temperature on the dynamic properties of the brush is not commonly referred to as an influencing wear parameter, and only a few studies have paid attention to these properties separately [17], [20], [22] and [25].The aim of this study was to analyse the effect of temperature on the dynamic properties of the copper-graphite brush and to compare it to the wear rate.The dynamic properties were investigated through the natural frequencies, the hysteretic damping ratio and evaluated through the material's properties, i.e., hardness tests and DSC, while the wear rate was measured previously, see, e.g., [26].This research is organised as follows: in Section 1 the experimental methodology is introduced, in Section 2 the experimental results with a discussion are presented, and in Section 3 the conclusions are given. …”

Wear Behavior of Graphic Brush for Motors in the High Humidity of Tropical Climate with Current

“…In contrast, the contact resistance decreased with an increased ambient temperature, electrical current, and rotating speed. The results were founded when studied electrical contact resistance and wear of a dynamically excited metal-graphite brush [19]. Hao Zhaohase studied electrical current, apparent contact pressure, sliding velocity, and electrical sliding wear behavior of Cu-Ti3AlC2 composites.…”