Direct current switching apparatus

Abstract

Direct current switching apparatus having two arc extinguishing chambers each comprising a pair of spaced conductors providing cooperable arc runners divergent toward a row of non-ferromagnetic splitter plates and a stationary contact conductively mounted on one conductor, the stationary contacts of respective chambers being mounted on respectively opposite conductors, corresponding conductors in respective chambers being conductively connected to each other and to power terminals of the apparatus, permanent magnets applying a magnetic field across the respective chamber for moving an arc within the chamber, ferromagnetic plates providing flux return paths to optimize and maximize the magnetic field, a movable contact extending into each chamber bridging the stationary contacts and movable to separate from the stationary contacts, drawing an arc therebetween in each chamber, the arc in one chamber bridging the pair of conductors within that chamber establishing a circuit comprising the arc between the conductors and the power terminals in shunt of the movable contact, thereby eliminating the arc in the other chamber, the bridging arc being extinguished in the splitter plates, interrupting the circuit. The magnetic fields are applied in opposite directions in the respective chambers for non-polarized operability of the apparatus and are distorted within the splitter plate area to drive and maintain an arc at a stable arc position against a thickened sidewall portion to withstand erosion.