Study of Some Influencing Factors of Armature Current Distribution at Current Ramp-Up Stage in Railgun

Abstract

Current ramp-up is an important stage for a railgun electromagnetic launch system. In lots of launching experiments, a big chunk of deposit aluminum can be found on the rail surface at the start-up position of the armature-rail contact area, sometimes, erosion is even emerged. The transition at current ramp-up is mainly related to local degradation of armature. The larger value of maximum current densities at the rail/armature (A/R) interface would lead to armature local temperature increasing rapidly, which deteriorates the material property of armature, degrades the static electrical contact performance, and reduces the railgun lifetime significantly. In this paper, for restraining start-up transition, several influencing factors of armature degradation and melt are studied based on current concentration. Rail resistivity, rail dimensions, armature resistivity, and the shape of current supply are considered and simulated. At current startup, skin effect and induced current are analyzed, which are considered as the direct factors of armature's current distribution. Armature current distribution and the maximum current density are obtained and compared for each factor. Finally, launching experiments are carried out as the same condition with simulation. On the rail surface at the start-up position of the A/R interface, the depositions reflect the current distribution on armature with different factors influence at the current ramp-up. The results of experiments are in reasonable agreement with simulation description.Index Terms-Armature current distribution, current ramp-up, influencing factors, the maximum current density.

Research on the Ablation Resistance of TiC Particle-Reinforced Aluminium-Based Composite Coatings on Armature Surface

“…In the process of electromagnetic launch, physical processes such as magnetism, heat, and force are coupled with each other. Under the combined action of friction heat, joule heat, and arc heat, the armature and rail will melt, splash, and even evaporate, and the formed metal vapor enters the gap between the armature and rail and transforms into a plasma state, which leads to the transition of the armature rail gun from good sliding electrical contact to destructive arc contact [33], thus causing more serious erosion to the metal material of the armature and rail.…”

Armatür Sargisinin Sarim Sayisinin Bi̇r Elektri̇kli̇ Araç Prototi̇pi̇ İçi̇n Tasarlanan Diş Rotorlu Firçasiz Doğru Akim Motoruna Etki̇leri̇

“…In the literature, it is observed that the heat density on the luminaire increases if this value is high. It is known that keeping the internal temperature of the motor low, as well as increasing the efficiency, will increase the motor efficiency and provide a more useful motor design [21]. ρ = (11) The expression of the self-resistance of the material is given in (11).…”

Analysis of an iron-core and ironless railguns powered sequentially

“…A leading theme of these studies is constructional solutions for increasing value of the magnetic flux density in the area where the projectile is accelerating (Min et al, 2015;Vincent and Hundertmark, 2015). The main problems with rail accelerators are a power source that generates a very high current peak (one or more times) from kiloamperes to even megaamperes in some milliseconds and constructional materials of rails and projectiles, which are exposed to dynamic influence of current during the operation of the device (Tang et al, 2015).…”