Abstract: A circuit interrupter particularly suitable for use in an oil filled distribution transformer having an elongated contact arm pivotable about one end with a movable contact attached to the other end through suitable insulating members to electrically isolate the movable contact from the elongated contact arm. The movable contact is a bridging contact for completing a series circuit through two stationary contacts. The movable bridging contact is spring biased away from the elongated contact arm. A retainer restricts the movement of the bridging contact away from the insulating members attached to the elongated contact arm. The biasing spring is disposed between the insulating members and the retainer. Grooves formed in the sides of the insulating members restrict rotational movement of the retainer and bridging contact. For larger circuit interrupters, a bridging contact assembly can be utilized having a plurality of parallel bridging contacts and a plurality of biasing springs.

Abstract: An enclosed circuit interrupter includes a removable drawout unit mounted within an enclosure and sealed by an enclosure door. The drawout unit is movable between a connected position and a disconnected position by a levering mechanism operated by a levering crank. A shutter prevents insertion of the levering crank unless the circuit interrupter is tripped by actuation of a trip plate. An interlock prevents removal of the inserted levering crank when the drawout unit is at any position intermediate the completely connected and completely disconnected positions. Closing of the enclosure door is prevented when the levering crank is inserted.

Abstract: A circuit interrupter including a drawout unit mounted within a sealable enclosure and operable between engaged and disengaged positions. A removable conductive safety barrier at ground potential is mounted on the front of the drawout unit and prevents any human contact with components at high potential. An interlock prevents removal of the safety barrier unless the drawout unit is in the fully levered out position. A hinged plate is operated by replacement of the safety barrier to allow the drawout unit to be operated to the engaged position.

Abstract: A power resistor including a resistance element of metal ribbon formed into an edgewound helix, and an internal three-point support structure axially disposed within the interior of the helix. The support structure includes three insulating assemblies each having a plurality of insulators secured by longitudinal compression springs to a support bar. The support structure also includes a pair of spreaders located at opposite ends of the helix, each having three radially extending arms. Assembly of the resistor includes the steps of inserting the insulating assemblies into the interior of the helix, radially spreading the insulating assemblies against the interior of the helix, and welding the ends of the support bars to the extending arms of the spreaders.