Experimental study on arc behaviors of a bridge-type contact when opening a resistive load in the range of from 280VDC to 730 VDC

Supply voltage of the dc power system in an electrical vehicle or an airplane keeps increasing with the increment of their electric energy consumptions, which raises a claim on high voltage contactors or relays. Special design on contact system or arc chamber in the contactor for arc quenching is necessary to meet the requirement of dc high voltage break. In this paper, arc behaviors when a bridge-type contact opens a dc resistive load are studied by analyzing arc shapes and waveforms of arc voltage and current. The power voltage varies from 280 V to 730 V, the current is kept to be 50 A, the material of contact is copper and the arcing gas is air. A cuboid permanent magnet is used to provide adjustable magnetic field for accelerating the arc quenching. Key arc parameters, such as arc durations, arc lengths, arc re-ignitions and the period that the arc stays on contact surface, are obtained as the power voltage increases from 280 V to 730 V and the magnetic field varies from 30 mT to 90 mT. The results are of practical value for designing the contact system of a high voltage dc contactor.