Abstract: A fail-fixed servovalve is provided for use in a digital control system. The servovalve is comprised of a deflecting means which deflects a jet pipe in response to an electrical input signal. Fluid flowing through the jet pipe causes a spool to translate within a sleeve, thereby allowing pressurized fluid to flow through selected ports within the sleeve to control the movement of an output piston. The output of the servovalve is essentially linear over the primary range of digital input currents with the output being zero when the input current is either zero or in excess of the maximum rated current for the servovalve.

Abstract: The coincidence circuit includes negative and positive signal processing means. The negative and positive signal processing means each includes level detector circuit means for developing separate level detector output signals for each one of a plurality of a-c input signals when each one of the plurality of a-c input signals is of a negative or positive value respectively greater than predetermined negative or positive threshold levels. The predetermined threshold levels are of different magnitude for at least some of the a-c input signals. AND circuit means is coupled to receive the level detector output signals of the negative and positive signal processing means for developing AND circuit output signals respectively representative of negative and positive phase coincidence of the a-c input signals with threshold level attainment.

Abstract: A bus conductor support system includes a tubular bus conductor removably mounted on an insulator assembly in a hollow conductive tubular enclosure. The tubular enclosure is secured to a mounting platform. Access openings are provided in the tubular enclosure for servicing purposes. One end of the insulator assembly is removably secured to the hollow tubular enclosure in a manner which allows easy access thereto through an access opening in the tubular enclosure. The bus conductor is removably mounted on an opposing end of the insulator assembly in a manner which also allows easy access thereto through the same access opening in the tubular enclosure. In one embodiment, a single side access opening in the tubular enclosure is in proximate relation to securing means for the insulator assembly and mounting means for the bus conductor.

Abstract: A ground and test apparatus is provided for use in combination with switchgear apparatus of the type which includes upper and lower circuit breaker compartments. The switchgear contacts in each of the compartments are disposed in a reverse order such that bus-side contacts are adjacent the lower portion in the upper compartment and adjacent the upper portion in the lower compartment. Similarly, line or load side contacts are adjacent the upper portion in the upper compartment and adjacent the lower portion in the lower compartment. The ground and test apparatus is of a configuration suitable for insertion into the upper or lower compartments and includes indicia means for visually indicating the proper location of the bus-side and line or load side contacts in the upper or lower compartments.

Abstract: This current limiting device comprises a normally-closed source-side circuit interrupter, a normally-closed load-side circuit interrupter, an electrical conductor connected between the interrupters for connecting the interrupters in series, and a normally-open switch that can be closed to connect the conductor to ground via a low-impedance conductive path located electrically between the interrupters. A switch operator acts to rapidly close the switch in response to a fault on the power circuit extending through the series combination of interrupters, thereby connecting the conductor to ground through the switch. The switch operator closes the switch within 1/4 cycle of power frequency current after fault inception, thereby effecting current-limiting action with respect to current through the series combination of interrupters on the load side of the conductive path to ground.

Abstract: This load-break fuse equipment comprises two draw-out fuse assemblies, one of the load-break type and one of the non-load-break type, each removably mounted in its own individual receptacle. The load-break fuse assembly and its receptacle comprise a load-break switch and a fuse electrically connected in series with each other. The non-load-break fuse assembly comprises a fuse, and this fuse is electrically connected in parallel with the fuse of the load-break fuse assembly and in series with said load-break switch.

Abstract: An electric circuit breaker includes means for providing a predetermined delay between the initiation of a command pulse and the mechanical operation of an element of the circuit breaker in response to the command pulse. In one embodiment, the predetermined delay is provided between a tripping command pulse and the mechanical operation of the trip mechanism of a vacuum circuit breaker. In this embodiment, a translatable armature is coupled to the trip mechanism through mechanical linkage including a flywheel rotatably mounted on a shaft. The shaft is mechanically coupled to the trip mechanism wherein rotation of the shaft operates the trip mechanism. The translatable armature is mechanically coupled to the flywheel so that movement thereof causes the flywheel to rotate through a predetermined rotation. The flywheel includes impact imposing means extending outwardly from a major face thereof. The shaft includes impact receiving means extending radially therefrom.

Abstract: The timer circuit includes ramping circuit means for producing a substantially linear ramping voltage output signal. Control circuit means is provided for receiving a timer input signal and controlling the ramping circuit means wherein the presence of the timer input signal causes the ramping voltage output signal to ramp with a positive slope. Level detector circuit means is coupled to the ramping voltage circuit means to receive the ramping voltage output signal and to produce a level detector output signal when the positively ramping voltage output signal is of a predetermined threshold. The level detector output signal continues as long as the timer input signal continues and is coupled back to the control circuit means. The presence of the level detector signal develops a truncating signal which causes the positively ramping voltage output signal to truncate. When the timer input signal terminates, the ramping voltage output signal ramps negatively and the level detector signal terminates.

Abstract: A new and improved control subassembly for HVDC power converters and method of its use during transient faults affecting the A. C. system employed in the HVDC power transmission system to assure the presence of adequate firing and commutating voltages across the respective HVDC thyristor valves during selected intervals of the alternating current periods of the respective phases. The HVDC power converters used in the system include gating circuits for gating-on respective ones of the thyristor valves during selected intervals of the alternating current periods of the respective phases. The gating circuits include equidistant-spaced gate firing pulse generating circuits for supplying equidistant-spaced gating-on firing pulses to the gate drives for the respective HVDC thyristor valves of the HVDC bridge power converter during normal operation of the converter in the presence of symetrically-shaped A. C. system voltage waveforms.

Abstract: A tubular pipe header is provided with an end surface which is substantially flat and in orthogonal relation to the longitudinal axis of the pipe header. An arcuate surface of a cylindrical transformer tank is provided with an aperture having a configuration at least a portion of which closely matches a portion of the end surface of the pipe header such that the matching end surface of the pipe header can be moved into the aperture when alignment therebetween is obtained. Another portion of the aperture includes non-matching means which prevents another portion of the end surface of the pipe header from moving into the aperture when alignment is obtained. In one embodiment, the non-matching means comprises tabs located in the same arcuate surface as the aperture. The tabs extend into the aperture. In aligning, the end surface of the pipe header is aligned with the aperture.

Abstract: A connector module for loadbreak operation having an insulating housing and a switch insert. The insert includes a container with a major portion of uniform diameter and a configuration such that the diameter does not increase from its outer end to its inner end. Inside the container is a snuffer-contact assembly. A bore contact having a gas port is attached to a snuffer tube of the assembly and has fixed to it a piston adapter for driving the snuffer-contact assembly toward the open end of the container tube in response to gas generated by arcing inside the bore. Resilient sliding contact means are fixed to the piston and press against the inside wall of the container tube to establish continuous electrical contact with it even while the piston is moving. A gas check valve member is resiliently seated against the inner side of the gas port. Keyways in the piston ride over longitudinal keyribs formed in the wall of the container to prevent rotation of the piston in the container.

Abstract: An electric fuse includes a cylindrical insulating housing with conductive terminal caps at opposing ends of the housing. Conductive ferrules are adjacent the terminal caps and electrically connected thereto. At least one main fusible element is disposed between the terminal caps and electrically connects the terminal caps. The ferrules are of a cylindrical configuration such that the fuse is operational through clip mounting of the ferrules. Bolt receiving means is provided for bolt mounting the fuse between a pair of conductive mounting bus bars. The bolt receiving means comprises a plurality of internally threaded passageways for securely receiving a threaded bolt. Each of the passageways respectively extends generally longitudinally inwardly through each of the terminal caps. The presence of the bolt receiving means presents substantially no impediment to the clip mounting operation of the fuse.

Abstract: A separable electrical connector assembly includes mating rod connector and bore switch modules. The bore switch module includes a grasping bore contact member for electrically engaging with a rod contact member which is included in the rod connector module. The rod contact member includes an arc follower at its engaging end. The assembly includes means for providing an operator, during a make operation, with a modified dwell position immediately following which electrical engagement of the rod and bore contact members is made. At the modified dwell position, further insertion of the rod contact member into the switch module is met by a noticeable resistance. At the modified dwell position, a predetermined distance separates the arc follower and the grasping bore contact member. In one embodiment, the bore switch module includes two axially spaced annular grooves respectively containing a gas sealing ring and a stop ring. The rod contact member includes two spaced annular recesses.

Abstract: A field terminated diode device includes contiguous anode, base, and cathode regions, which are respectively P+, N-, and N+ semiconductor material. The N- base region includes therein a grid region of P type semiconductor material. The grid region includes grid openings which define channels in the grid region for communicating charge carriers between the anode and cathode regions. Means are provided for electrically connecting to the anode and cathode regions and to the grid region. In one embodiment, the grid channels are nonuniform in that their average widths increase from the center to the perimeter of the device. In another embodiment, the nonuniform channels are distributed throughout the grid region.

Abstract: A bracket of generally U-shaped cross-section comprising spaced-apart legs terminating in edges having projections thereon is joined to a cylindrical steel wall by a method that comprises the steps of: (a) locating the bracket so that said edges extend along the length of the cylindrical steel wall and said projections contact the external surface of the wall, (b) projection-welding the bracket to the wall by an operation that collapses the projections, locates the edges closely adjacent the external surface of the steel wall, and provides a gap of V-shaped cross-section between each edge and the external surface of the wall, and (c) then fillet-welding the bracket to the wall by applying a welding fillet to the external surface of the wall and the outer surface of each leg of the bracket in the region of the V-shaped gap.

Abstract: A voltage regulator to provide a wide range of regulation, especially useful with process control. The regulator is provided with an extra bushing connected to the exciting winding of the regulator. By this means two or more regulators may be connected with their exciting windings in parallel and their series windings in series to provide a desired wide range of regulation. The invention also encompasses a selector switch so that the regulator operating at the top of the regulating range may be interchanged with one or more other regulators to alternate the tap-changing duty among the various regulators. Automatic operation of the regulators is disclosed.

Abstract: This operating system comprises a fluid motor having a piston, a breaker-opening space at one side of the piston, and a breaker-closing space at its opposite side. An accumulator freely communicates with the breaker-opening space for supplying pressurized fluid thereto during a circuit-breaker opening operation. A normally-closed valve located on the breaker-closing-side of the piston is openable to release liquid from the breaker-closing space so that pressurized liquid in the breaker-opening space can drive the piston in an opening direction. Means is provided for restoring the valve to its closed position following the circuit-breaker opening operation. An impeded passage affords communication between the accumulator and the breaker-closing space to allow pressurized liquid to flow from the accumulator to the breaker-closing space and develop a pressure therein substantially equal to accumulator pressure when the valve is restored to closed position following breaker-opening.

Abstract: A ground distance relay employing phase angle comparator measurement is provided with additional input signals. In one embodiment, a two input ground distance relay is provided with two additional input signals. In this embodiment, the first two input signals comprise an OPERATE SIGNAL of the form IZ-V and a POLARIZING SIGNAL of quadrature shifted form. The third input signal comprises a #2 POLARIZING SIGNAL which is related to the zero sequence voltage at the relay. The fourth input signal comprises a CURRENT SUPERVISION SIGNAL which is related to the zero sequence current at the relay. These four input signals are directed to coincidence and timer circuitry. The presence of these four inputs provides improved relay security against undesirable relay operation for several existing problems. For example, additional security is provided for situations in which a single line to ground fault occurs at or just beyond the relay balance point where fault resistance may cause undesirable relay operation.

Abstract: A high voltage combination fuse has a current limiting section which has a free standing, helical coil of fusible wire material. The support for the free standing coil comes only from the pulverulent arc quenching material which fills the fuse casing and surrounds the coil. The coil has a foot portion and a head portion of increased cross-section to avoid arcing in the immediate vicinity of the end caps. The foot and head portions are preferably formed by doubling back a length of wire at the respective end and wrapping the tip of the doubled back length around the wire.

Abstract: An operating device for an electric circuit breaker includes a closing spring and a rotatable spring-controller mounted for rotation between first and second dead center positions with respect to the spring. The spring is charged by transmitting rotational forces to the spring-controller. One end of a connecting link is pivotally connected to a point on the spring-controller which is eccentric with respect to the center of rotation of the spring-controller. Another end of the connecting link is connected to an operating mechanism of the circuit breaker. Circuit breaker closing is effected by allowing the spring to quickly discharge after a charging operation. Damping means is provided for imposing a damping load on the spring-controller substantially only after it has performed its useful work and is undergoing subsequent oscillations. The damping means causes the duration of the oscillations to be substantially reduced so that the spring-controller is rapidly brought to rest.