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This paper is devoted to study the influence of ferromagnetic material on arc behavior in low voltage electric apparatus. With the self-programmed interface, one 2-D magnetohydrodynamic arc model can be developed based on the commercial software FLUENT and ANSYS, to study the vapor of ferromagnetic material effects on air arc behavior. Then, the corresponding interruption experiments are performed to verify the simulation qualitatively. It demonstrates that the vapor of ferromagnetic material is disadvantageous to arc interruption characteristics. In addition, the influence of the size of the ferromagnetic splitter plate on arc motion is simulated. It shows that the bigger splitter plate may accelerate the arc motion. Index Terms--Arc, ferromagnetic material, interruption performance, magnetohydrodynamic (MHD) model, vapor.

This paper is concerned with the investigation of the motion of an air arc plasma in a quenching chamber, in particular with the effect of different chamber widths and outlet areas. A simplified arc chamber of a low-voltage switch device is used for the analysis. Based on a set of governing equations, a 3-D air arc plasma model is constructed and solved by a commercial code. It is found that increasing both the chamber width and the outlet area leads to an increase in the arc speed, but the strength of the dependence varies, depending on the values of the chamber width and the outlet areas. The tail of the arc column becomes shorter as the chamber width is reduced. This is shown due to the reduction in the backward flow by the squeezing of the two flow vortices that occurs. Index Terms--Air arc plasma, arc chamber, arc movement, simulation.

Arc-motion process is crucial to the interruption capability of the low-voltage circuit breaker. First, to a simplified chamber with full open venting, with a 2-D optical-fiber arc-motion measurement system, experiments were done to measure the arc-motion velocity in order to analyze the influence of different arc ignition position on the arc motion. It demonstrates that the larger the volume behind the arc is, the slower the arc moves. In addition, the influence of the gassing material on arc-motion velocity was also studied experimentally. Then, the commercial computational fluid dynamics software FLUENT was adapted and modified to develop a 2-D magneto-hydrodynamic model of the arc with the same conditions as the experimental model. The simulation result was consistent with the experiment conclusions. Index Terms--Arc motion, circuit breaker, gassing material, magneto-hydrodynamic.

This paper is devoted to the study of the air arc plasma characteristics and consists of two parts. An optical high-speed imaging system is integrated with pressure sensing, arc current, and voltage measurement to investigate high-speed and high-temperature unsteady arc plasma motion in a molded case circuit breaker (MCCB) model, especially with the influence of polyoxymethylene (POM), polycarbonate (PBT), nylon, and ceramic arc chamber wall materials. It demonstrates that the performance can be improved effectively by adopting POM and nylon gassing materials. Also, spectrum diagnostics is introduced to analyze the influence of polymethylmethacrylate (PMMA) gassing material on the temperature of arc in a simple model. It shows that material added adjacent to cathode is more effective to cool the arc, compared with the case of anode. Index Terms--Arcing, circuit breaker, gassing materials, measurement, spectroscopy.

Air circuit breaker (ACB) is widely used in power distribution system. The movable contact of ACB consists of multiple parallel contacts and the arc will be ignited between arcing contact and static contact when the short-circuit current appears. This paper focuses on the arc evolution process at various currents in multiple parallel contact systems. A 3-D magnetohydrodynamic model of a multiple parallel contact structures is developed. In this model, the anode consists to five parallel contacts, and they are separated by insulation material. The near-electrode layer with a nonlinear voltage–current density characteristic is modeled to describe the near-electrode voltage drop, and the difference between near-anode and near-cathode layers is considered. The magnetic vector potential approach is adopted to calculate the time-varying electromagnetic field produced by the current loop. The arc evolution processes at various currents are analyzed by current density and arc voltage. It is noted that the anode arc root appears on multiple contacts with the increase of current. The arc evolution process mainly depends on the arc resistance characteristic. [ABSTRACT FROM AUTHOR]