Abstract: A contactor having main and auxiliary contacts and an arc quenching system including a blowout coil. The blowout coil is connected in series with a first and second set of auxiliary contacts and the resulting series combination connected in shunt around the main contacts. The second set of auxiliary contacts is arranged to open after the first auxiliary closes and before the main contacts close in order to remove the blowout coil from the circuit when the main contacts are carrying load current.

Abstract: Means for causing the properly-polarized one of a pair of series-connected DC contactors to open before the other, depending upon the direction of load current flow. Load current is caused to link the magnetic circuit constituted by a contactor coil, frame and armature; with current flowing in a first direction, the linking has an additive effect, strengthening the MMF in the magnetic circuit. When current flows in the opposite direction, the MMF is weakened which allows the contactor to open more quickly.

Abstract: A DC contactor providing increased magnetic efficiency, reduced contact bounce, and shorter arc time has a movable contact carrier bar pivotally mounted relative to a clapper armature so as to prevent tilting about its longitudinal axis and eliminate rotational bounce; a pre-loaded contact pressure spring which resiliently urges the contact carrier bar against the armature; an armature retainer spring which resiliently urges the pivoted end of the armature backward and downward against the yoke so as to displace dirt accumulated in the pivot area and prevent jamming of the armature; a generally hyperbolic magnetic pull characteristic with the knee at approximately the one-half armature travel position and the magnetic pull at the two-thirds armature travel position being approximately twice the magnetic pull at the knee to thus provide relatively high magnetic pull per ampere in the region above the knee; the magnet gap between armature and core at the point of contact engagement being less than that at the k

Abstract: The contacts of a DC contactor operating in a contaminated atmosphere are prevented from welding as a result of jamming of the armature by a thin nonmagnetic shim which is mounted on the armature so that it is disposed in the closed magnetic circuit and retains a dirt-shielding gasket above the armature pivot area so that falling dirt cannot accumulate between armature and yoke where it might, absent the gasket, interfere with closing of the armature and thus result in reduced contact pressure and increased heating of the contacts.

Abstract: An auxiliary interlock switch for a DC contactor has a reciprocable one-piece insulating contact carrier and plural bridging contacts interchangeably mounted thereon in alternative positions to provide different desired arrangements of normally open and normally closed contact sets with the stationary contact posts. The contact carrier has a return spring compressed within a spring-receiving cavity and elongated abutment-receiving apertures registering with opposite ends of said cavity through which an abutment member, that is releasably assembled to the contact carrier, may interchangeably freely extend to permit relative movement therebetween and against which one end of the return spring reacts to resiliently bias the contact carrier against reciprocation in one direction.