Abstract: In order to facilitate the installation of off-premises equipment which distributes CATV signals from a distribution cable to subscribers and to allow different subscribers to receive different classes of service (basic service alone or with one or more premium or pay-per-view channels), a pair of housings are used, one containing circuits for tapping the signals from the cable and the other for electronics hardware which processes the signals and distributes them to subscribers in accordance with the class of service which is ordered by the subscribers. The housing containing the tapping circuits is permanently connected to the cable and need not be removed or replaced when connecting additional subscribers or changing the class of service. The housing containing the electronics hardware for processing the signals may be attached to or along side of the first housing. The first housing may be suspended from the strand which supports the cable in an aerial mount configuration.

Abstract: The invention is directed to an improved scrambler capable of self-calibrating output signals. In one embodiment, the scrambler provides an encoded signal along separate signal pulses. A portion of one signal is made to correspond to a portion of another signal to thereby self-calibrate the signals. Also, portions of the incoming video signal are forced to correspond with internally generated voltage level signals.

Abstract: A circuit breaker having an automatically adjusting magnetic armature is provided. The magnetic armature includes a spring-biasing means to automatically maintain one end of the armature in the contact with the electromagnet and the other end away from an adjacent electromagnet. The magnetic armature includes a pair of slightly curved arms which are disposed about a pivot guide post. When current through the circuit breaker exceeds a predetermined amount, the end of the armature normally biased away from the adjacent electromagnet is suddenly attracted to the electromagnet. The force from the spring-biasing means is overcome, and the slightly curved arms of the armature pivot about the pivot guide post so that the armature contacts the adjacent electromagnet. A latch holder at the end of the armature becomes disengaged from a latch means to cause the circuit breaker to open.

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 electric distribution panel is constructed with an insulating base formed by extrusion. Also extruded with the base are two rows of circuit breaker mounting ledges, hook formations for each of the mounting ledges to mechanically secure circuit breakers at the load ends thereof, and channel defining formations to slidably receive neutral bars disposed outboard of each of the mounting ledges. A tie bar extends transverse to the neutral bars and provides an electrical connection therebetween. Wiring guide elements are slidably received by appropriate formations of the base and in particular the base is provided with elongated apertures to receive annular embossments of one of the wiring guides elements so as to permit expansion of the base without buckling thereof even though the mounting surface for the distribution device does not expand at the same rate as the base.

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.

Abstract: An improved system for sensing current flow in a single phase or polyphase circuit to be protected and deriving a single signal representing composite current flow. A ramp-like reference signal is applied to one input of a comparator at sampling intervals, and the outputs of a plurality of current amplifiers coupled to the other comparator input so that the duration of a change in signal output level of the comparator is an inverse function of composite current. An accumulator stage stores portions of incoming current signals less a predetermined fraction of previous accumulator contents. In the event of circuit interruption the accumulator is decremented in a manner which reflects the inferred thermal history of the system.

Abstract: An improved anti-rebound mechanism for circuit breakers having a blow-off, current-limiting feature is provided. The improvement consists of a ferromagnetic latch which is activated by any massive current surge through the circuit breaker sufficient to cause blow-off current interruption. The latch is caused to be magnetically attracted to, and engage with, a notch on a movable arm of a circuit breaker to maintain the arm in an open position until the circuit breaker is manually reset in a closed position.

Abstract: A circuit interrupter of the type including an arc chute and separable contacts between which an arc may be drawn is provided with flash plates. The plates are disposed at either side of the region in which an arc forms and serve to protect the adjacent interrupter housing, while assisting in channeling the arc into the arc chute. The flash plates are formed of a ceramic material and are provided with a plurality of grooves running the direction generally transverse to the direction of the arc.

Abstract: An easily visible condition indicating device to signify a lack of pressure within the envelope of an electrical interrupter of the type utilizing a pressurized-gas environment. The system includes a rotatable drum contained within a housing having an aperture through which the drum is viewed. When pressure within the interrupter drops a spring-biased bellows collapses, causing the withdrawal of stops which hold the drum in place against spring tension. This allows a biasing spring to rotate the drum so that a different portion thereof, such as a different colored segment, is viewed through the housing aperture in order to provide a visual indication of a low-pressure condition.

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 direct acting undervoltage release device utilizes stored spring energy to trip a circuit breaker when the control voltage reduces to a critical level (the "undervoltage"). The device includes a solenoid that senses the undervoltage, and a charging motor that automatically resets the device after a tripping operation (provided the control voltage recovers to its normal level). The direct acting feature is achieved by providing a chargable trip spring and a trip pin in the circuit breaker which directly drives the latch bar of the breaker to trip the breaker.

Abstract: A tap changer voltage regulator permits a tap changer selector contact to engage an open circuited new tap without arcing and has a half-tap voltage auxiliary winding which permits halving the inter-tap voltage to thus double the number of steps, and an auxiliary switch with a pair of movable contacts. A first auxiliary contact initially connects a selector contact which has moved to a new tap through a circulating current limiting resistor to a load, preventing load current interruption. A second auxiliary contact is in series with a normally-closed switch through which load current and circulating current flow. A first set of inverse parallel SCR's is in series with the resistor, while the normally-closed switch is shunted by a second pair of inverse parallel thyristors. The first pair of thyristors is not gated until the first auxiliary contact has attained its new position, precluding initial arcing.

Abstract: A rotor having cast squirrel cage windings is provided with a number of spacers for interrupting or spacing the stacked rotor laminations, thus forming vents for cooling. The spacers surround the rotor bars, and have a projection at each side thereof for fitting into the adjacent laminations. The design of the spacers allows them to be narrower than those previously known, thus enhancing air flow through the rotor.

Abstract: The rotor assembly comprises a shaft, a rim structure, and a spider for connecting the rotor rim to the shaft. The spider structure incorporates a number of rigid arms which are secured to and extend radially from the shaft. The ends of the rigid arms are secured such that free radial motion of the rotor rim is permitted with respect to the spider, but angular motion between the rotor rim and the spider is prevented. The rotor assembly further contains a plurality of flexible cross beams and associated floating arms. The cross beams extend between adjacent spider arms, while the floating arms are firmly connected between the middle section of the cross beams and the inner surface of the rotor rim. The cross beams flex in and out in radial directions as the rotor rim contracts and expands, respectively, due to centrifugal or thermal forces.

Abstract: An improved limited-travel linkage for "cracking" a gas blast valve in a circuit breaker. A projection from a portion of the circuit breaker linkage travels along an arc in interfering relationship with a spring-loaded latch on a crank. Movement in one direction engages the latch, turning the crank and cracking the valve. Arc quenching gas then flows through a conduit to the interrupter contacts to blow out the arc drawn between them.

Abstract: Bearing adaptable for use in dynamoelectric machine for preventing current from flowing through the bearing itself. A three-part layer including a base material, a ceramic layer, and an adhesion layer is applied sequentially upon the bearing shell. The last layer is then covered with a bearing material, ordinarily babbitt so that the babbitt, is electrically isolated from the bearing shell.

Abstract: An air disconnect switch incorporates a unique arrangement of an ice breaking self-polishing current transfer horn arrangement which transfers the current to a puffer-type interrupter to effect circuit interruption prior to the disconnect switch being fully opened; the puffer-type interrupter is a dielectric insulated device which has its operating mechanism disposed within the dielectric insulating medium so that the system has no fast-moving external parts and provides a direct drive with minimum maintenance of the mechanism parts. The porcelain tube serves both as the interrupter housing and as the mechanism housing.

Abstract: A tap changer voltage regulator permits a tap changer switch selector contact to engage an open-circuited new tap without arcing and has a half-tap voltage auxiliary winding which permits halving the inter-tap voltage and doubling the number of steps, and also has an auxiliary switch system. An auxiliary static switch circuit initially connects a first tap selector in series with a circulating current limiting resistor and a load to prevent load circuit interruption. An auxiliary selector switch initially coupled to a second tap selector and is in series with a normally-closed switch through which the load current and circulative current flow. The normally-closed switch is shunted by a second static switch circuit. The first static switch is not gated until the first tap selector has attained its new position, precluding initial arcing.

Abstract: A shielding arrangement for preventing the buildup of ice on the contacts of an outdoor high-voltage switch structure. The shield includes one or more flexible members which overlie the contacts and are in the path of the travel of a switch element.