Arc Behaviors of Three Kinds of Bridge-type Contacts when Opening a Resistive Load in Range of from 300VDC to 750VDC

The DC contactors are widely used with the development of DC power system, which raises a claim on high voltage and long lifetime contactors. The designs on contact system and arc chamber in the contactor are necessary for arc quenching and meeting the requirement of DC high voltage break. In this paper, arc behaviors when three kinds of bridge-type contacts (traditional bridge-type contact, bridge-type contact with two parallel contact, bridge-type contact with four series contact) open a DC resistive load are studied by analyzing arc shapes and waveforms of arc voltage and current. The power voltage varies from 300V to 750V, the current varies from 30A to 100A, the material of contact is copper and the arcing gas is air. Two cuboid permanent magnet are used to provide adjustable magnetic field for accelerating the arc quenching. The arc duration, the arc lengthening time and the arc blowing time can be obtained as the power voltage increases from 300V to 750V, the current increases from 30A to 100A. The magnetic field keeps 100mT. The results are of practical value for designing the contact system of a high voltage and long lifetime DC contactor.