Abstract: A puffer interrupter has two axially spaced movable pistons fixed to the movable contact. A fixed barrier is disposed between the two pistons and a further fixed barrier is positioned at the end of the cylinder chamber. The two fixed barriers form three variable volume chambers with the two movable pistons. As the interrupter is opened, the central chamber formed between the end movable piston and fixed barrier between the two pistons reduces in volume to generate an increasing pressure while the two volumes on either side of the central volume increase in volume to produce a decrease in pressure. Gas then flows axially through the separating contact from the decreased volume central chamber to the outer reduced-pressure chambers. An auxiliary piston is formed within the central chamber and can increase the central chamber volume when the pressure within the central chamber exceeds a given value due to blockage of the nozzle by high arc-generated pressures.

Abstract: A high-voltage power circuit breaker contains a plurality of phases which are contained in respective separate tanks which may be filled with sulfur hexafluoride. Each phase contains a respective trip-free contact operating mechanism connected to the interrupter contacts within the tank. Each of the trip-free operating mechanisms are closed simultaneously by a pneumatic closing mechanism contained in only one of the poles and connected to the other pole operating mechanisms by a common operating rod. Each of the poles are simultaneously closed by the pneumatic operating mechanism, and each pole can open independently of the other poles through its own trip-free operating mechanism.

Abstract: A high voltage switch has a molded plastic support base which carries contact terminals at its opposite ends and on the front surface of the base. Switch contacts are connected to the terminals. The support base is hollow and its interior and exterior surfaces are slotted or projections are added to increase electrical creepage from the switch support to the switch contacts. The support base has openings for receiving elongated bus terminals to allow rear connection of the switch terminals rather than front connection to the front switch terminals. A rotatable operating shaft is mounted at the rear of the base and connected to the switch blade by insulation operating links. A suitable operating mechanism is fixed to the operating shaft at one end thereof.

Abstract: A stationary contact of an electromagnetic contactor having an insulating contact mounting plate is part of a contact combination that includes a contact arm, a retainer and a fastening screw for electrically and mechanically securing the contact combination to a terminal of the contactor. The contact is mounted on the forward end of the arm and the retainer, constructed of spring sheet material, engages the rear of the arm. The front of the arm and the retainer cooperate to form a recess which receives and grips a formation of the mounting plate.

Abstract: A unitized combination motor starter includes a unitized insulating base for an electromagnetic contactor section and a circuit breaker section having automatic trip means. The unitized base is part of a common insulating housing for the contactor and circuit breaker sections and circuit elements serially connecting these sections are disposed within the common housing.

Abstract: A magnetic trip means for automatically opening a circuit breaker contact upon the occurrence of predetermined fault current conditions is constructed of a stationary yoke, an armature biased away from the yoke and movable toward the yoke for tripping of the switch, an actuating coil in series with the contacts, and a sealed capsule coaxial with the coil for obtaining selected tripping characteristics. Within the sealed capsule there is a movable magnetic core biased to a normal position extending substantially outside the coil. The core is movable inside of the coil toward the armature upon the occurrence of overload current conditions with movements of the core toward the armature being retarded in a controlled manner. Control is obtained by closely spacing the outer cylindrical wall of the core and the inner cylindrical wall of the capsule, and additionally by utilizing a viscous fluid within the capsule.

Abstract: An electric switch mounted within an enclosure having a hinged cover is manually operated from outside the enclosure by a handle mechanism secured to the enclosure. The cover is provided with a single aperture near the edge thereof remote from the cover hinges, with this aperture providing clearance for the operating handle and housing of the mechanism when the cover is closed and also providing clearance for a catch which holds the cover closed. A defeatable cover interlock prevents opening of the cover when the switch is closed, and a defeatable switch interlock prevents closing of the switch when the cover is open. The handle mechanism housing is provided with a front recess having a pivoted indicator member therein which is connected by a wire link to the cradle of the trip free contact operating mechanism.

Abstract: An electric switch mounted within an enclosure having a hinged cover is manually operated from outside the enclosure by a handle mechanism secured to the enclosure. The cover is provided with a single aperture near the edge thereof remote from the cover hinges, with this aperture providing clearance for the U-shaped operating handle of the mechanism when the cover is closed and also providing clearance for a catch which holds the cover closed. The mechanism also includes a defeatable cover interlock to prevent opening of the cover when the switch is closed, and a defeatable switch interlock to prevent closing of the switch when the cover is open. Each interlock comprises a flat member biased to an active position by a U-shaped wire spring, positioned for cooperation with different arms of the operating handle, and mounted for movement in planes perpendicular to the cover when the latter is closed.

Abstract: A conduit hanger includes an inverted U-shaped bracket having laterally spaced depending legs swingable supporting at their bottoms closure arms. The closure arms are swingably between a closed position extending toward each other and gravity urged toward such position and being urged upward under pressure to an open position providing bottom access between the bracket legs. One or both closure arms may be provided with openings proximate their inner ends and the other arms may be provided with depending legs for engaging a respective opening. In another form, a closure arm projects through an opening in one bracket leg toward the other and is pivotted at its outer end to the bottom of a link whose top is pivotted to the upper outer face of the bracket leg.

Abstract: A single pole molded case circuit breaker is constructed with an internal metal frame to which the contact operating mechanism is mounted. This mechanism includes a releaseable latch for maintaining the mechanism cradle in its reset position wherein the circuit breaker contacts may be closed. The latch is a plate-like element having an integrally formed ear that directly engages the cradle for latching thereof. A socket rivet provides a cantilevered support for the latch on the frame. This rivet is keyed to the latch so that operation of the latter may be coordinated with operation of an external device.

Abstract: A molded case multi-pole circuit breaker is provided with a solid state trip unit constructed to automatically open the breaker responsive to predetermined fault current conditions by actuating a permanent magnet latch. The circuit breaker is also provided with a thermal-magnetic trip means that acts independently of the solid state trip unit to automatically open the breaker responsive to predetermined fault current conditions.

Abstract: A hybrid circuit breaker consists of a series-connected vacuum interrupter and sulfur hexafluoride interrupter wherein the contacts of each are simultaneously operated. The sulfur hexafluoride interrupter is of the type in which an arc is rapidly rotated through a relatively static volume of sulfur hexafluoride. In one embodiment of the invention, the vacuum interrupter is replaced by a second sulfur hexafluoride interrupter in which the arc gap between the electrodes receiving the final arc to be interrupted is relatively smaller than the corresponding arc gap in the other sulfur hexafluoride interrupter.

Abstract: A multipole circuit breaker is constructed with a single rod pivotally mounting all of the movable contact arms to a common one piece molded insulating carrier. Individual torsion springs engage each of the contact arms to provide contact pressure when the circuit breaker is closed. The construction of the contact arms and carrier are such that under severe overcurrent conditions electrodynamic blowoff forces acting on the contact arms may bring about contact separation that is substantially as great as the contact separation that takes place when the circuit breaker is opened normally by its contact operating mechanism.

Abstract: An electric motor for driving a circuit breaker operating handle is connected to the latter by two sets of linkages. The first set of linkages includes a drive arm and a driven arm mounted on fixed spaced centers and interconnected by a cam means. The drive arm is pivoted by connection to the drive motor through gearing and a slip clutch, and mounts a roller entered into a cam slot formed in the driven arm. The second set of linkages consists of a drive link and a main link also mounted on fixed spaced centers with the main link having means for engaging and moving a circuit breaker operating handle. The drive and main links are connected by a roller-slot arrangement, with the roller being positively guided along an arcuate path formed about a center remote from the centers of the links and arms. Positive guidance of this connecting roller causes the effective lengths of the links to change in accordance with different positions of the circuit breaker handle.

Abstract: A single pole molded case circuit breaker is constructed with an internal metal frame to which the contact operating mechanism is mounted. This frame provides the pivot bearings for main elements of the mechanism as well as having integrally formed stops for certain of these elements.

Abstract: A cutter for corrugated aluminum flexible pipe having a plurality of successive circumferential corrugations. The cutter frame is formed of two members hinged at one end and releasably closed at the other end to form a ring, a guide wheel or wheels ride the crest of one corrugation and a resiliently flanged wheel or wheel opposed to the first guide wheel or wheels ride the trough on either side. The blade is connected adjacent to one or between a pair of resiliently flanged wheels which permit the blade to be driven into the pipe. The C members are resiliently compressed toward each other by an adjustable spring controlling bolt which sets the pressure on the blade and allows for proper cutting even when the pipe varies in diameter. A handle recess or recesses on the ring receives a handle to rotate the ring for cutting.

Abstract: A single pressure sulfur hexafluoride circuit interrupter is contained in a bottle or elongated, cylindrical housing filled with gas under moderate pressure. The bottle contains arcing and main contacts arranged generally along the axis of the bottle and arranged to separate from one another in the vicinity of a pair of spaced conductive rings fixed relative to one another, and which serve as arc runners. Each of the rings is connected in series with a respective coil which is wound on the axis of its respective ring and which encircles the cooperating contact and conductors therefor. The coils and the conductive rings create a magnetic field which spins an arc drawn between the spaced short-circuited rings through the sulfur hexafluoride gas, thereby to extinguish the arc.

Abstract: A multipole molded case circuit breaker of moderately high rating is constructed of a stack of single pole units each having a contact operating mechanism and a trip unit. The movable contact arm is so positioned that it is subjected to magnetic blow-off effect, which even at relatively low fault levels, tend to open the contacts to enduce a current limiting action. A conducting strap within each pole unit housing is connected to the line terminal and is provided with a plurality of spaced connecting points each accessible through a different opening at the rear of the housing for connection to a panelboard bus bar.

Abstract: A multi-pole circuit breaker is provided with a molded common trip bar means including a bar having integrally formed bearings defining a pivot axis remote from the bar, integrally formed links individually connected to the overload sensing means of each pole, and an integrally formed projection for releasing a latch of a trip free contact operating means.

Abstract: An over-voltage protection apparatus includes an over-voltage detector measuring the voltage between each energized conductor and a neutral or ground line associated therewith series connected between an A.C. power source and a utilization device and an over-current protection device, such as a circuit breaker, to disconnect the conductors from the energy source in the event the voltage on any one of the energized lines exceeds a predetermined threshold voltage. Suitable over-voltage detectors consist of any device which is non-conductive for all input voltages less than a threshold voltage and are conductive after the input voltage has exceeded the threshold voltage.The over-voltage protection apparatus described is applied to A.C. power circuits having at least one phase and at least two wires. Use of the apparatus to also provide protection in the event of an open neutral line condition, when unequal loads are present between at least two energized conductors and the neutral line is also described.