Study on Arc of Electromagnetic Relay Contacts Opening a DC Low Current Resistive Circuit with a Constant Velocity

摘要

An electrical arc appears on the contacts of relay when opening a current above the minimum arc current in a circuit. A Magneto Hydro Dynamics (MHD) model was employed to simulate this dynamic arcing process. The distribution of arc parameters such as temperature, electrical field, and magnetic flux density when breaking a 5A-DC-low-current was obtained. The behaviors of arc parameters with the length of gap between contacts increasing were also simulated. Then this MHD model was combined with structured dynamic layering which is one of the dynamic meshing techniques of computational fluid dynamics (CFD) to calculate the dynamic arcing process, and the arc parameters when breaking a 5A-DC-low-current with a constant velocity were also obtained. It turns out that the computation of time-varying contact voltage and arc duration agrees well with the test results so that the validity of simulation can be proven indirectly.