Abstract: A contactor interlock assembly operable with a racking arrangement for engaging and disengaging a contactor unit with a bus bar arrangement disposed relative to a contactor unit support structure. The contactor interlock assembly includes an arrangement for disabling the racking arrangement when the contactor unit is "ON." A cable connects the racking arrangement to a lever bracket supported by the support structure which is operated by a lever on the contractor unit. The lever operates the lever bracket which causes the cable to disable the racking arrangement. The interlock assembly may also include a second lever bracket associated with a second contactor unit. The second lever bracket is coupled to the first lever bracket by a cable such that the contactor units are also interlocked, such that the operation of one contactor unit is made dependent upon the operation of the other contactor unit.

Abstract: A bus bar stab and insulator assembly for a motor controller has a two-piece housing and a three-piece stab finger clip. The housing base has a number of partitions which define pathways for the stab fingers. The housing cover is slidably mateable with the base and has a tab for receiving a self tapping screw. The stab fingers extend from the housing for making contact with bus bars. The stab finger clip has two fingers with interlocking tabs secured together with a screw which also connects one or more connector cables to the clip. The fingers are constructed of copper alloy and do not require the use of springs.

Abstract: A bus bar stab insulator shroud cooperates with a bus bar stab housing to insulate and protect the stab fingers. The shroud includes an insulative member which has first and second side members connected by a central member which has first and second openings of a size sufficient for receiving stabs of a bus bar stab.

Abstract: A mechanical interlock is provided for a vacuum contactor assembly to insure that the second contactor cannot close after the first contactor closes. The interlock includes a support bracket, a cover plate and an interlock block which was first and second openings and is positioned between the support bracket and the cover plate. First and second ball bearings are positioned in the openings. The cover plate and interlock block are connected to the support bracket. First and second slide members each have an operating arm and a blocking arm with appropriate openings for cooperating with the ball bearings and interlock block openings. The operating arm of one slide is paired with the blocking arm of the other slide so when one operating arm moves the ball bearing it blocks the other slide from moving thereby preventing one of the vacuum contactors from operating.

Abstract: A load break switch and interlock assembly is housed in a cabinet with a door. The switch assembly is oriented 90.degree. from a normal position along the backwall of the cabinet and is located on a sidewall. The switch handle protrudes through the front of the cabinet. The handle is horizontally oriented to interfere with the door when the switch is closed thereby preventing the door from being opened. When the switch is open, the handle is vertically oriented and does not interfere with the door.

Abstract: A shutter mechanism is provided for a motor control center of the type having a backwall with a stab opening for receiving a stab connector for making electrical contact with bus bars which are behind the panel. The shutter consists of two pieces, a stationary member which has a central opening and a vertical slit opening into the central opening and a movable member which has a guide thereon and is positioned between the motor control center and the stationary member with the guide extending through the slit and vertically movable therein. The stationary member is fastened to the motor control center with the central opening overlaying the stab opening. The movable member moves from a closed position to an open position and then from the open position to the closed position under the force of gravity alone without the use of springs.

Abstract: An operator is provided for a molded-case circuit breaker of the type in a motor controller where the circuit breaker is removably mounted on a pan brace which is held in place by a pan latch. The operator mounts on the breaker for opening and closing the breaker and for providing three interlocks. One interlock prevents withdrawal or insertion of the breaker with the operator handle in the "on" position. A second interlock prohibits closing or opening the control door except when the handle is off and a third interlock locks the operator handle in "off" position.

Abstract: A motor control center of the high voltage type which includes a set of three vertically-disposed cubicles. The two lower cubicles house a pair of contactor assemblies, the lowermost contactor assembly being longer than the upper one. The cubicle enclosing the upper contactor is provided with a partition behind which is a compartment containing vertical bus bars. The lowermost cubicle extends beneath this compartment so that the bus bars drop directly down to engage a set of connectors which are also engaged by the lowermost contactor assembly.

Abstract: An improved drawout carriage assembly for the contactor of a high voltage controller. The controller carriage is fabricated from a pair of sheet metal sides, interconnected at their lower edge by formed sheet metal cross members. The upper portions of the sides are comprised of planar sheets of insulating material. A series of insulative cross members are bolted between the opposed faces of the carriage side pieces and locate elements of the contactor mechanism.

Abstract: A lever-type handle for operating a racking mechanism and providing an interlock for a cabinet enclosing electrical equipment. The handle is comprised of two sections which are linked together by a throughbolt. A cover assembly retaining and enclosing a portion of the handle is provided with an opening oriented so that the bolt is only accessible when the handle is in an "on," or energized, position. By removing the through bolt the handle sections are disengaged so that one portion can be moved to a non-locking position and access gained to the cabinet interior.

Abstract: An improved mechanism for racking a contactor mechanism within an enclosure. The mechanism is urged into a fully-engaged position by an arm extending from a rotatable cross shaft which in turn is operated by a pair of complementary four-bar linkages. The first linkage in effect consists of a handle, connecting rod and bellcrank, the second consisting of the bellcrank and another arm, affixed to the cross shaft. An improved spring-loaded detent arm assists in holding the handle in the "racked on" position and a pivoted interlock engages the bellcrank in two positions.