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.

Abstract: A circuit maker and breaker has a removable arc chute for interrupting an arc formed between the movable and stationary contacts. A pivotally movable interlock device is mounted in a cavity in the insulating base of the circuit maker and breaker in the region where the contact-carrying armature is movable into engagement with a magnetic yoke to close the movable contact of the circuit maker and breaker into engagement with the stationary contact. The pivotally movable interlock device includes a plug-like member which is movable into the path of movement of the contact-carrying armature to prevent closure of the armature if the arc chute is not properly positioned on or is absent from the circuit maker and breaker. The interlock device is actuated by a lever which is engaged by a surface on the arc chute as the arc chute is slid into proper position on the circuit maker and breaker, to thereby move the interlock device out of plugging or blocking relation to the armature.