Abstract: An in-depth review of the switchboard business, including customer interviews, revealed that customer specifications were more complex than customer needs. Customer needs were quantified, and a reduced set of standard switchboard configuration classes was selected so that about 80% of customer orders based on actual customer needs could be satisfied by the standard switchboard configuration classes, and the remaining orders would be satisfied by custom designed switchboards. Major components in the standard switchboards were themselves standardized. A standard switchboard, for example, has a continuous current capacity of no more than 4000 Amps, a maximum voltage rating of 480 Vac, a short circuit current rating of no more than 200 kA, and an aluminum or copper bus. The manufacture of the standard switchboards was optimized for a one-day manufacturing cycle and separated from the manufacture of the custom designed switchboards.

Abstract: A circuit protection apparatus employs a PTC element for overload and/or short circuit protection and an arcing fault interruption arrangement. The circuit protection apparatus may be employed in a ground fault receptacle for interrupting the flow of electrical current in a line in response to any of a plurality of different types of fault conditions on the line. The circuit protection apparatus may include a set of contacts connected in series with the line, and having an open position and a closed position, a trip device coupled to the contacts, adapted to be actuated by a trip signal, to move the contacts from the closed position to the open position and an element having a positive temperature coefficient of resistivity (PTC) connected in series with the contacts. The PTC element is connected to the trip device to provide the trip signal to the device in response to overload or short circuit conditions in the line.

Abstract: A number of methods can be used for zone arc protection to detect series and/or shunt arcing faults in various electrical components and/or circuits. A differential current detector, or a di/dt based detector, may be used to detect shunt arcs, while a differential voltage detector or a zero-sequence voltage detector, is used to detect series arcs. A differential phase current detection scheme may be used for both shunt arcs and series arcs. Series arcs may also be detected using a voltage drop system or a line power loss system. Detection of arcing in joints may be monitored directly. A ground fault detector may be combined with one or more of these systems for detecting a ground fault in the circuit to be protected. Two or more of the above systems or detectors may be combined for arc monitoring and detection.

Abstract: An improved viewing window construction for an electrical disconnect switch 10. The improved construction of the viewing window 70 permits easier installation of the viewing window 70 while at the same time reducing the complexity of the switch cover manufacturing process, eliminating the need for a window retainer 46 and increasing the resistance to the ingress of water when subjected to a stream of water under pressure.

Abstract: A power conversion system is described which includes a power input for accepting a waveform at a given power level and frequency, and a power output for providing an output waveform at a second given power level. A DC to AC converter accepts a waveform based on an input wave form from the power input and converts the waveform to an AC waveform having a frequency at least approximately an order of magnatude higher than the frequency of the input waveform for application to a DC to AC converter output. An AC converter accepts the output waveform from the DC to AC converter output and provides a converted waveform from an output of the AC converter to the power output. A coupling device operates at the frequency of the converter output for coupling the output of the DC to AC converter to the AC converter.

Abstract: A dual power source retrofit kit for a single power source service entrance panel. The retrofit kit is a field installable kit for retrofitting a single power source service entrance panel to a dual power source service entrance panel. The kit includes a power source selection assembly and a mounting bracket for attaching to the service entrance panel. A deadfront trim plate having a cut-out to accept the power source selection assembly is also supplied to replace the old trim plate of the service entrance panel. The power source selection assembly permits only the selected one of the primary or auxiliary power sources to provide power to the service entrance panel at any one time. The power source selection assembly is also designed such that overload protection devices/disconnect switches for both the primary power source and the auxiliary power source must be in the OFF position before switching from one power source to the other is permitted.

Abstract: An operating shaft which provides compensation for axial and spatial misalignment between a rotatable component mounted within an enclosure and a rotating apparatus generally outside the enclosure is disclosed. The operating shaft has a first end dimensioned to be slidably received within a receiving portion of the rotating apparatus such that the shaft is maintained in a fixed angular position with respect to the rotating apparatus. The shaft is axially slidable with respect to the rotating apparatus such that it will provide compensation for axial misalignment between the rotatable component and the rotating apparatus. The shaft has a second end configured to engage the rotatable component such that rotation of the rotating apparatus will produce a corresponding rotation of the rotatable component. The shaft also has a spatial compensation device which is integrally formed from the shaft between the first and second ends.

Abstract: A multiplex extender 26 for permitting discrete I/O devices 34, not individually equipped to decode multiplex channel addresses, to be multiplexed on a time division multiplexed control bus 10. The multiplex extender 26 is connected intermediate the time division multiplexed control bus 10 and a branch line 30 and includes a multiplex channel address decoder 78, a data disconnect switch 82 and a branch line controller 90. The multiplex channel address decoder 78 is selectively programmed to one of the multiplex channel addresses of the time division multiplexed control bus 10. The multiplex channel address decoder 78 produces one or more output signals, each being determined by the multiplex channel address which has most recently been decoded.

Abstract: A circuit protection apparatus includes a circuit breaker coupled in series with a circuit to be protected. The circuit breaker has a trip input and is responsive to a trip signal at the trip input for changing from a closed circuit condition to an open circuit condition to thereby remove electrical current from the circuit to be protected. A thermal trip element is coupled in series with the circuit to be protected and is responsive to a predetermined current/time characteristic of current flow in the circuit for delivering the trip signal through the thermal trip element to the trip input.

Abstract: A circuit for initiating the setting of a series brake upon detecting a loss of armature current in an overhauling DC crane motor. The circuit includes an ammeter shunt, a meter relay and associated contact, a meter relay power supply, a control relay and associated contact, a low current relay and associated contact and two static timers which can be added to an existing crane operating circuit. The ammeter shunt is located electrically in series with motor armature for monitoring current flow in the armature. The meter relay is connected to the ammeter shunt such that it will operate in response to a signal from the ammeter shunt indicating that current in the motor armature has dropped below a predetermined level. The meter relay requires power for operation, this power being provided by the 24 VDC power supply.

Abstract: A phase control system has a stable timebase phase reference generated by an internal phase reference generator. The control includes a method for estimating and compensating phase distortion when an inductive load is driven by an AC voltage source having significant line impedance. A digital phase comparator estimates a phase error between the timebase phase reference and the voltage source. At the initialization of the phase control system, the phase reference clock period is frozen for a fixed number of cycles to determine an average phase error due to the phase distortion caused by the line impedance. The estimated phase error is then corrected to account for the average phase distortion error.

Abstract: An operator interface unit for monitoring and controlling controllers coupled to a communications network has a common database that is accessible across the network, regardless of each controllers data structure. The operator interface unit provides an apparatus for displaying, storing, and editing data obtained from the network. Data from each controller can be accessed by the unit based upon the individual controller's data structure and type through embedded objects resident in the interface unit's operating system and program. The data can then be displayed, edited, and stored by any data entry device that is capable of executing the operator interface unit's program.

Abstract: A communications network is used to couple weld controllers and different operator interface units together, regardless of their data structures. An arbitration system provides a means for one operator interface unit to communicate to a selected weld controller at a given period of time. The operator interface units have one of three modes of operation. These include database master, primary master, and secondary master. During setup of the communications network, the master devices are assigned a physical address that defines the its type and priority within the network. The database master is the only device which can automatically download data to a weld controller. It has the highest priority as a network arbiter. The primary master will act as the network abitrator in the absence of a database master. A secondary master must listen for an access grant from the current network arbiter, before initiating a message packet on the network.

Abstract: A linear operating mechanism for a slotted optical switch 10 which produces a guaranteed OFF-point for a consistent linear displacement of a switch operator 58 with respect to a reference surface 66 of the device enclosure 62. The guaranteed OFF-point is consistently repeatable from one device to another. The device enclosure 62 defines an integrally formed support for receiving an emitter 14 and a receiver 18 of the slotted optical switch 10. The enclosure 62 further defines a fixed Off-plane 114 immediately adjacent the receiver 18 and precisely located with respect to a reference surface 66 on an outside surface of the enclosure 62. The switch operator 58 is received within the optical switch slot and has a distal end 86 extending outside the enclosure 62 a precise distance with respect to the reference surface 66 when the operator is in a normally biased first position.

Abstract: A self diagnostic system is integrated into an application program for controlling a machine or process. The application program is comprised of various logical segments that have to be solved by a logic solving engine. The diagnostic program will annunciate an event when the application program cannot execute a desired response by monitoring certain preselected and marked segments of the application program and allocating memory to save the result. When an abnormal occurrence in these segments results in the desired event not occurring, the diagnostic system will determine what part of the logic expression controlling the event could not be completed. This information will be saved and used for annunciating the reason for the desired event not happening. The diagnostic system includes a special control module that is added to the application program.

Abstract: A circuit breaker for interrupting electrical current flowing through a line conductor to a load terminal in response to the detection of a current overload, ground fault and/or arcing fault. The circuit breaker has a trip circuit to generate a trip signal, a releasably latchable trip lever, and a latching mechanism. The trip lever is moveable between a latched position and a tripped position. In the latched position, the trip lever engages the latching mechanism and the electrical current flows through said circuit breaker. When a fault is detected by the trip circuit, a trip signal is send to the latching mechanism. Upon receiving the trip signal, the latching mechanism disengages the trip lever allowing the trip lever to slide into the tripped position and interrupting the current flow through the circuit breaker.

Abstract: A meter stack wherein each single phase meter base in the meter stack can be selectively connected in the field to any one of the A-B, A-C or B-C phase combinations of the vertical three phase bus bars in the meter stack by moving only the meter base line connectors. The vertical bus bars of the meter stack lie in a common plane and are equally spaced apart from one another. The vertical center line of each meter base in the meter stack coincides with the center line of the center vertical bus bar of the meter stack. Each of the two line side terminals of each meter base is associated with one of the outside vertical bus bars, and is located approximately half way between it's associated outside vertical bus bar and the center bus bar. A generally "Z" shaped line connector attached to each of the line terminals can be easily rotated between its associated outside bus bar and the center bus bar, thus easily allowing a change in the A-B, A-C or B-C phase combinations of each meter base.

Abstract: The present invention provides a terminal assembly 18 and method for connecting an electrical connector to an electrical distribution device. The device has a housing 12 with an interior surface defining an interior space 16. The terminal assembly 18 includes a clamp body 20 having a first surface 26 and a second surface 28. A portion of the first surface extends downward to define an interior wall 30 of a cylinder. The interior wall 30 extends perpendicularly to the first surface 26. A substantial portion of the interior wall 30 of the cylinder has threads 40. A fastener 24 has a head at one end of an elongated body and screw threads 60 near the opposite end. The screw threads 60 being adapted to engage the threads 40 on the interior wall of the cylinder of the clamp body 20. A clamp plate 22 has a plate body 50 which is partially defined by a top surface 52 and a bottom surface 54. The plate body 50 has a plate aperture 56 for accommodating the fastener 24 through the plate body.

Abstract: A circuit breaker including a switch having an open and a closed position connected to a line of the circuit breaker. A first actuating device, actuated by a first activating signal, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted. A positive temperature coefficient resistivity element (PTC element) is tripped at least once wherein the tolerance of the PTC element is reduced and the PTC element is connected to the first actuating device for providing the first activating signal. In another embodiment of the present invention, a second actuating device, actuated by a second activating signal provided by the circuit breaker current, is connected to the switch to move the switch from the closed position to the open position wherein the flow of electric current in the line is interrupted.

Abstract: An arcing fault protection system for a switchgear enclosure includes a grounding device for rapidly grounding the source bus of an electrical distribution system in response to the detection of arcing faults in the system. The grounding device, which may comprise a mechanical switch, a solid-state switch or hybrid device, quickly diverts current carried on the source bus to ground to effectively extinguish arcing fault currents present in the distribution system, preventing the generation of gases at hazardous pressures and/or temperatures so as to protect the switchgear equipment from damage and to prevent injury to operating personnel.