Abstract: A trip unit connection tester (10) is arranged to test the electrical connections (12) and (14) between a trip unit (16) and actuator (18) mounted within a circuit breaker (20). Tester (10) includes a power source (64) including a positive lead (68), and a negative lead (70). The positive lead (68) is coupled to a two-loop switch (58). The two loop switch (58) toggles between a first loop (98), and a second loop (100). The first loop (98) includes the power source (64), the two-loop switch (58), and the energy storage element (82) wherein the energy storage element (82) stores energy coming from the power source (64). The second loop (100) includes the two-loop switch (58), and the energy storage element (82), connections (12) and (14), and the actuator (18), wherein energy stored within the energy storage element (82) is released to the actuator (18).

Abstract: A method and apparatus generates an enhanced trip time curve capable of capturing both the non-sinusoidal energy and series effects. Relevant data including time, current, and energy is plotted on a three-dimensional set of axes. The resultant three-dimensional representation is useful for representing trip times for a protection device accounting for energy effects, and for determining selectivity in a multi-tier electrical distribution system.

Abstract: This circuit is inserted between a terminal (RGB) and a line (LI). The signal of the input terminal (RGB) is applied to the base of a bipolar amplifier transistor (T2) mounted with a top load (LR1) and a bottom load (LR2). A series transistor (T1) mounted in series in the main signal path has its collector wired up as an electrode for receiving the input signal, its emitter feeds a line (LI), and its base is linked by a resistor to the collector of the second transistor.

Abstract: A circuit breaker system (100) providing application specific module (ASM) instantaneous overcurrent indication is disclosed herein (FIG. 5). A trip unit (110) included in the circuit breaker system (100) is powered by an external power supply unit (134) in the ASM (104). The circuit breaker system (100) includes transmitting an indication signal (130) from the trip unit (110) to the ASM (104) in response to an overcurrent condition. The indication signal (130) triggers a first controller (130) included in the ASM (104), the first controller (130) configured to cause the external power supply unit (134) to maintain power to the trip unit (110) for a first length for time sufficient to communicate a data corresponding to the overcurrent condition to the ASM (104).

Abstract: A power line testing device has a signal generator that is adapted to be connected to one of a plurality of AC branch circuits, and generates an identification signal. This identification signal will be strongest in the branch circuit of origin. A receiver of the testing device senses the strength of the identification signal, compares that strength to a stored identification signal, and is therefore able to identify to which AC branch circuit the transmitter is connected.

Abstract: A non-automatic power circuit breaker includes separable contacts for movement between a closed position and an open position, and an operating mechanism for moving the separable contacts between the open and closed positions. A time-delayed making current release switch is closed for the open position of the separable contacts and is opened a predetermined time after the separable contacts move to the closed position. A low permeability air core current transformer senses an electrical current flowing in a current conductor for the separable contacts and provides a signal corresponding to the electrical current. An analog trip unit employs the signal corresponding to the electrical current and the making current release switch signal corresponding to the open and closed positions of the separable contacts and provides a trip signal. The analog trip unit includes a comparator for disabling the trip signal when the making current release switch is opened.

Abstract: A PCM module arrangement includes a three phase circuit breaker and PCM electronics unit. Each phase of the circuit breaker has a Rogowski coil at the line side and load side contacts in a vacuum bottle and another zero sequence current sensor encloses the load side conductors of the circuit breaker to provide a zero sequence current signal. A PCM electronics unit is provided with phase current measurement signals from the Rogowski coils. The PCM electronics unit provides a direct interface for various signals including a signal from a supervisory control and data acquisition system.

Abstract: A circuit arrangement is described for monitoring an electronic tripping device for low-voltage switches having a microprocessor device which, in conjunction with a digital-analog converter, evaluates an overcurrent so that line power supply system. The microprocessor device (MPE) has a zero crossing comparator with which a constant test current pulse is transmittable, at zero crossings, to the electronic tripping device via an additional current transformer winding to measure the amplitude. In the case of deviations from the setpoint value, (re)calibration or actuation of the line tripping contacts, with an alarm signal being emitted, takes place.

Abstract: A system including a load center monitor (10) connected to a plurality of digitally enhanced circuit breakers (40) by a communication bus (26) forms a network of reconfigurable circuit breakers which provides advanced monitoring and control of an electrical power distribution system. A user port (20) and a service port (22) provide a communication interface with an external computer. Visual indicators (34) and an audible alarm (30) provide for alerting persons to certain conditions in the system. Buttons are provided for CLEAR (38), RESET (36), and TEST functions, and a diagnostic port (24) is also provided. The load center monitor (10) is operable to monitor the operation of the circuit breakers (40) and download information therefrom for storage in the load center monitor (10) as in the form of historical data.

Abstract: A method and apparatus for over current backup protection is provided. The method generates a set of root mean square (rms) values from samples that are taken from the system current. Several rms current values are averaged to generate an estimated rms over current value. The estimated over current value is compared with a predetermined threshold value. If the estimated current is above the predetermined threshold value, a fault protection mechanism, such as opening a circuit breaker, is activated. A generator protection unit having digital signal processing capabilities executes the inventive method to provide protection from over current episodes.

Abstract: The present invention involves a power circuit breaker that conditionally and temporarily enables instantaneous trip protection. A position sensor senses whether the breaker contacts are open or closed. When the breaker contacts are open, the circuit breaker enables the instantaneous trip protection. After the circuit breaker contacts are closed, the circuit breaker continues to enable the instantaneous trip protector for a predetermined period of time. After this time delay, the circuit breaker disables the instantaneous trip protection and the circuit breaker reverts to providing its ordinary protection, such as long-time or short-time protection.

Abstract: An encapsulated tubular conductor having at least two antenna elements disposed on the capsule thereof for maintaining therebetween wireless information transmission in a transmitting-receiving direction, and a transmitting-receiving device located outside the capsule and assigned to one of the antenna elements includes another transmitting/receiving device also disposed outside the capsule and assigned to the other of the antenna elements, the antenna elements being directed towards an interior space of the capsule, the interior space serving as a transfer path via which information is transferable between the transmitting-receiving devices.

Abstract: Faults occurring in a telecommunications system are monitored identifying their time of onset and reporting them to an operator through an interface if they have not cleared within a predetermined interval. Transient faults, which do clear within that interval, are not reported directly, but only if such faults occur more frequently than a predetermined rate. This is determined by establishing a scan interval, and an analysis period equal to a plurality of scan intervals, monitoring the system continuously for the occurrences of faults, and storing their times of occurrence in a store. At the end of each scan interval, the number of occurrences of the fault during the analysis period which ends at the end of the scan interval are counted by a counter. If the number of occurrences of the fault in the analysis period is equal to or greater than a threshold value selected by user input, an alarm indicator is activated.

Abstract: A microcomputer 4 responds to an instruction signal to turn the load L on or off to control the FET 2 through the drive circuit 5. The microcomputer 4 samples an electric current I.sub.L which is supplied through the A/D converter 6 and which flows in the load L at every predetermined sampling time T.sub.S and subjects the sampled electric current I.sub.L to a comparison with a known rated current value I.sub.R for the load L. When I.sub.L .gtoreq.I.sub.R is satisfied, the microcomputer 4 starts counting energizing time T. When the accumulated value of I.sub.L .times.T.sub.S is enlarged to a predetermined value S.sub.O, the microcomputer 4 turns the FET 2 off. When the detected electric current I.sub.L is larger than an upper limit I.sub.O (>I.sub.R) determined previously, the microcomputer 4 immediately turns the FET 2 off through the drive circuit 5.

Abstract: An electronic trip unit for a circuit breaker having two current sensors per phase, wherein the first magnetic core current transformer is designed to monitor current in the normal and overcurrent range, and the second low-permeability core sensor is designed to produce an override trip signal at or below the short time withstand current rating of the circuit breaker. In a second embodiment the electronic trip unit includes only the low-permeability core sensor that has negligible output in the normal current range.

Abstract: A circuit breaker includes separable contacts for movement between a closed position and an open position. An operating mechanism moves the separable contacts between the closed and open positions and has a closed state and an open or tripped state which corresponds to the open position. A trip circuit senses electrical current flowing through the separable contacts, employs the sensed current to trip the operating mechanism to the tripped state to move the separable contacts to the open position, and provides plural status signals. A display circuit cooperates with the trip circuit and includes light emitting diodes for outputting the status signals. A battery powers the display circuit which further includes an oscillator circuit for modulating the LEDs to reduce power from the battery to the display circuit.

Abstract: The circuit breaker comprises a circuit breaker unit onto which there are fixed a communication module, a processing module and a calibration module. The communication module communicates with the processing module only via a connection with galvanic isolation, preferably an optical connection, whereas the calibration module is electrically connected to the processing module. The communication module is, in addition, connected by a mechanical connection to parts of the circuit breaker unit representative of the state of the circuit breaker, and by a bidirectional electrical connection to an external communication bus. An interface connected to the circuit breaker unit can act as support for the calibration module and for an additional module containing information representative of the breaking capacity of the circuit breaker and electrically connected to the processing module.

Abstract: A circuit breaker includes separable contacts for movement between a closed position and an open position. An operating mechanism, which moves the separable contacts between the closed and open positions, has a closed state and an open or tripped state which corresponds to the open position. A current transformer senses electrical current flowing through the separable contacts as a sensed current. A trip mechanism employs the sensed current for tripping the operating mechanism to the tripped position to move the separable contacts to the open position. The trip mechanism includes a microprocessor which generates short delay and ground fault trip functions of electrical current and time. The microprocessor inputs a first interlock signal from a downstream electrical switching device which generates the first interlock signal with a first value when current through the downstream device exceeds a predetermined value and with a second value otherwise.

Abstract: A method for configuring a digital overcurrent relay to provide a plurality of selectable time overcurrent characteristic responses corresponding to a plurality of target curves. According to one embodiment, a template curve is selected from the plurality of target curves, and a scaling factor is generated for each remaining target curve, wherein the relay comprises means for generating approximated curves from a given template curve and a given scaling factor. It is determined whether each approximated curve is within a threshold amount of total error with respect to its corresponding target curve. If any approximated curves are above the threshold amount, then a further template is selected from the plurality of target curves, and scaling factors are again generated and adjusted for the further template curve, until no approximated curves are above the threshold amount.

Abstract: A power controller for a powered device such as a heating/air conditioning unit that monitors and controls the supply of power to an individual heating/air conditioning unit and shuts off power to the powered device when the voltage level of the power supplied to the unit falls outside a predetermined range. The power controller also transmits telephonic alarms and receives touch tone commands over telephone lines. The power controller may be equipped with a device for sensing the presence of a fire.

Abstract: A portable programming device is provided for communicating with and downloading tripping characteristics to a circuit breaker electronic trip unit. The programming device incorporates an umbilical cable which is attached to a connector on the trip unit, over which power is supplied to the trip unit and data is exchanged, a keypad with function keys including On/Off, Function, Breaker/Pane, Sensor and Program keys, and a LCD display which is capable of showing pertinent parameters such as circuit breaker type, sensor size, pickup and delay settings, current flowing through the circuit breaker and the trip characteristics to be downloaded to the trip unit. The portable programming device has a provision to operate from power supplied by a built in battery or from an external AC adapter. The programming device is presented with a fiber optic cable which, when coupled to a trip unit which is attached to a powered circuit breaker, can pass data to the device display.

Abstract: A current sensing module for use with a variable speed AC motor control drive system for use with devices such as treadmills and including a module to sense the current of pulse width modulated signals provided to an AC motor wherein the current sensing module includes a fast sense circuit to sense excessive current conditions in the pulse width modulated signals and a slow sense circuit to sense average current values in excess of desired values over a predetermined period of time to protect the AC motor from damage caused by the increased frictional resistance to the rotation of the walk belt on the treadmill deck as the walk belt and treadmill deck wear out.

Abstract: A motor starter for an electrical circuit including a power source and a load, includes an electrical contactor having separable contacts for switching an electrical current flowing between the power source and the load, and an operating mechanism responsive to a trip signal for opening and closing the separable contacts; a current sensor for sensing the electrical current flowing between the power source and the load and providing a sensed current value therefrom; and an overload relay including a microcomputer routine for generating the trip signal as a function of a trip current value and at least one of: (a) a test current value, and (b) the sensed current value; and a test routine including at least one of: (a) a first selecting mechanism including a routine for selecting a first predetermined value as the trip current value and a routine for selecting the test current value for use by the microcomputer routine with the trip current value, and (b) a second selecting mechanism for selecting one of at leas

Abstract: A testing apparatus for testing a sample fault indicator (11) of the type which has a current sensor (15), an automatic reset, an inrush restraint feature, and an indicator display (13) that are widely used by electric utilities for fault location of overhead and underground distribution power circuits. The first objective of the testing apparatus is to test the predetermined current threshold level of the sample fault indicator (11) which is specified by the producer. It provides for the simulation of a fault current condition by means of a pulse driver circuit (99). The output response of properly working fault indicator (11) under this test will cause the indicator display (13) to register a fault state. The second object provided by this apparatus is to test the automatic resetting of the sample fault indicator (11). It provides for simulating a reset signal (105) for a controlled duration of time.

Abstract: A fault current sensor device detects and distinguishes abnormal current events on alternating current overhead and underground power transmission lines. The sensor distinguishes whether the momentary or sustained fault is a line-to-ground fault, line-to-line fault or a three-phase fault. The sensor determines whether the overload has occurred on all three phases, or only on one or two phases, of the power line in an unbalanced situation. The device can be remotely reprogrammed to alter its trigger or threshold level and can be remotely reset after a fault has occurred.

Abstract: An intelligent circuit breaker or switching device system comprises three separate microprocessor-based units, including a condition monitoring unit (CMU) 40, a breaker control unit (BCU) 50, and a synchronous control unit (SCU) 60. The CMU 40 provides detailed diagnostic information by monitoring key quantities associated with circuit breaker or switching device reliability. On-line analysis performed by the CMU provides information facilitating the performance of maintenance as needed and the identification of impending failures. The BCU 50 is a programmable system having self-diagnostic and remote communications. The BCU replaces the conventional electromechanical control circuits typically employed to control a circuit breaker or switching device. The SCU 60 provides synchronous switching control for both closing and opening the circuit interrupters. The control processes carried out by the SCU reduce system switching transients and interrupter wear.

Abstract: A microprocessor based overcurrent trip unit includes an analog circuit for monitoring phase currents in the electrical interrupting device. The analog circuit is adapted to interface with the microprocessor over a range of selectable setpoints for instantaneous tripping and at the same time accurately monitor the phase currents even during a condition when the current sensing transformers are saturated. The overcurrent trip unit also allows the function of the long time delay characteristics of protection curve to be varied in order to provide better coordination with the characteristics of other overcurrent tripping devices in an electrical distribution system, such as a current limiting fuse, thereby enhancing the overall reliability of the system. For example, the function may be varied to provide either a fixed or FLAT, It, I.sup.2 t and I.sup.4 t functions.

Abstract: An electronic instrument that records electric power measurements. The instrument contains two types of memories: the first type of memory can tolerate wide fluctuations in ambient temperature but is expensive per unit of storage capacity, and the second type of memory only operates in a narrow ambient temperature range but is inexpensive per unit of storage capacity. For example, the two types of memory may be static Random Access Memory (RAM) and a hard disk drive, respectively. The instrument contains more storage capacity of the second type than storage capacity of the first type. The instrument records all of its measurements in the first type of memory. It also monitors the ambient temperature. When it detects an ambient temperature that will permit the second type of memory to function properly, it flushes the first type of memory into the second type of memory, thus creating space for recording subsequent data in the first type of memory.

Abstract: An integrated circuit breaker having several accessory functions along with automatic overcurrent protection, allows selection between the various accessory functions in different combinations. Separate switches are arranged on the circuit breaker to allow factory as well as field selection of the accessory function combinations.

Abstract: A solid state sensing and control device for monitoring either D.C. or A.C. currents of one or more phases that is ideal for protecting motors and other A.C. loads. The programmable monitoring device can detect an overload or an emergency and virtually instantaneously interrupt motor current to prevent burnout and reduce the danger of fire. High current conductors leading to the motor (or other load) are mechanically routed through current sensing coils. An LCD visible through the cabinet top displays menu information and data. Programming and command control are initiated by pressing one or more of a plurality of light buttons disposed beneath the cabinet that comprise OPIC transmitter-receiver pairs. An instrumentation amplifier is associated with each sensing coil, and the circuitry preferably outputs two amplified analog signals from each coil, the amplitude of the first being proportionately higher than the second.

Abstract: The present invention provides a circuit breaker trip unit configured to operate with a plurality of different plug-in display units. The display unit includes a memory which stores data representative of the particular display unit, and which allows the trip unit to automatically adapt to communicate with the display modules. The trip unit includes a processor and programming which permits a bi-directional flow of data between the units, such as display data and control data.

Abstract: A graphical representation of the current/time trip characteristic displayed on the operator's panel of an electronic trip unit for a circuit interrupter, has different indicia, such as different colors, identifying the representation of independent trip functions from those of dependent trip functions, thereby making the operator aware that adjustment of one of the dependent trip functions will also affect an adjustment of the other dependent portions of the current/time trip characteristic.

Abstract: A low voltage electric power monitoring and circuit breaker system includes two processors. The first processor activates the circuit breaker when an overcurrent condition is detected and the second processor monitors the current sensed by the first processor and logs overcurrent values which arm the breaker as well as overcurrent values existing at the time the breaker is tripped.

Abstract: A microprocessor based switch such as a circuit breaker has a memory capacitor charged by the microprocessor to generate an analog equivalent of a digitally modelled heat state signal. A selected resistor discharges the capacitor at a rate which models a cooling rate of a load. Alternatively, the memory capacitor may be charged to a preset value and discharged at a rate representative of the time since a trip generates digital rms representations of analog load. Terminals for rapidly resetting the analog trip memory for calibration and field testing of a long delay trip are hidden behind a removable rating plug.

Abstract: A low voltage electric power monitoring and circuit breaker system includes two processors. The first processor activates the circuit breaker when an overcurrent condition is detected and the second processor monitors the current sensed by the first processor and activates the circuit breaker for overcurrent conditions which should have caused the first processor to activate the breaker. If a current of this magnitude is detected, the second processor activates the circuit breaker as a backup protection for the first circuit breaker.

Abstract: A circuit breaker includes an electronic trip device which responds to sputtering arc-type faults. Level detectors compare the current in the protected circuit to a plurality of threshold levels and timers time the intervals that the current remains above each threshold, with the threshold levels and intervals selected to generate a response envelope for a trip signal which approximates, with a selected margin, the response of the protected circuit to introduction of a selected inductive load such as the starting of a motor into the circuit. If the sensed current falls below a threshold level which was being timed, the associated timer is not cleared unless the current falls below the lowest threshold, so that if the sensed current increases above the associated threshold, timing resumes where it left off, and a trip signal will be generated sooner than for an initial excursion above the threshold. Both analog and digital timer implementations are presented.

Abstract: A hybrid monolithic IC that is standardized for controlling various types of electrical equipment, such as circuit breakers, motor controllers and the like. The IC is a hybrid monolithic IC, fabricated in CMOS technology, The shortcomings of utilizing CMOS technology for linear or analog circuitry is overcome by the implementation of the IC to provide a monolithic IC that is relatively less expensive than using multiple ICs or a single IC fabricated from biCMOS technology.

Abstract: An apparatus provides an electrical connection (113) between an RF shield (109) and a printed circuit board (115) in a radio communication device (100). A spring member (211), having a free end (209), extends laterally from the RF shield (109). The free end (209) includes an edge (317) formed by the angular displacement of a triangular portion (315) from a bottom surface (307) of the free end (209). The flexible nature of the spring member (211), under load, drives the free end (209) into the printed circuit board (115) such that the edge (317) is imbedded into solder (205) disposed on a conductive circuit (207) on the printed circuit board (115).

Abstract: A solid state circuit interruption arrangement monitors a current path to provide protection to both a load and a solid state switch. The arrangement includes an energy absorber for absorbing energy from the current path in response to the solid state switch interrupting the current path, and a control circuit for periodically generating the interrupt signal to interrupt the current path for prescribed intervals and to control the current supplied to the load between a maximum current level and a minimum current level.

Abstract: The short time delay circuit comprises a counter which is zero reset when the signal representative of the current is greater than or equal to a threshold, and controls count-down of an up-down counter, when the content of the counter reaches a preset value. A clock circuit controls the count-up and count-down frequency of the counter and up-down counter.

Abstract: To perform the long delay function of an electronic trip device, a quantity (TLR1) representative of the thermal current state varies proportionally to the difference (I.sup.2 -Is.sup.2) between the square of a value (I) representative of the current flowing in a conductor to be protected and the square of a current threshold (Is). This first quantity (TLR1) is used in combination with a second value (TLR2) to produce a tripping signal when the second value exceeds a preset value (TLR2max). The second quantity preferably increases proportionally to the square (I.sup.2) of the value representative of the current, when the first quantity exceeds a preset threshold (STLR1) and decreases, preferably exponentially, when the first quantity is lower than this threshold.

Abstract: In a circuit breaker having an instant time tripping test function, terminals which are connected to an electric power source of a control circuit of the circuit breaker and a quasi over-current signal generating circuit for tripping test are provided on a front face of a housing of the circuit breaker, and a widely usable detachable tripping tester comprising a D.C. power source and a switch is connected to the terminals, thereby a predetermined voltage is applied to the electric power circuit and the quasi over-current signal generating circuit for testing a tripping mechanism.

Abstract: A circuit breaker has leakage current detecting functions, that is leakage detection, leakage alarm and disconnection the circuit in the leakage state from the power source side; in order to conduct such functions, the circuit breaker comprises a magnetic release device for disconnecting a circuit in the leakage state, a zero-phase current transformer for detecting a leakage current, a sensitivity selector, an amplifier and a leakage relay for issuing a leakage alarm signal.

Abstract: A digital circuit interrupter having a keypad and display for entering and viewing the trip parameters utilizes a sampling algorithm to periodically sample the current within a protected circuit. The sampling algorithm allows a real time constant sampling interval independent of wide variations in the power system frequency.

Abstract: Low voltage electric switchgear equipment includes a central programmer unit electrically interconnected with electronic main and branch circuit interrupters within the same enclosure and used with a multi-phase power distribution circuit. Indicating diodes are arranged on each of the circuit interrupters for signaling the occurrence of an overcurrent condition. The same indicating diodes are arranged for responding to address commands generated by the field programmer as to the exact location of each circuit interrupter within the enclosure.

Abstract: An inrush restraint in a fault indicator disables trip in response to the current in the cable being monitored changing from reset to trip values within a predetermined period.

Abstract: A faulted circuit indicator includes an inrush restraint circuit that suppresses a trip signal when an inrush current rises from below a minimum value to a trip value within a predetermined time and then drops again to another value such as the trip value. According to various aspects the restraint ends after a fixed time or after a variable time. According to another aspect a second trip circuit overrides the inrush restraint circuit when the current rises a given amount beyond the first trip value.

Abstract: A circuit breaker containing an electronic trip unit utilizes a digital keypad and display to enter and display the trip parameters. The trip parameters are determined by means of a setpoint value that is incremented by means of an algorithm whenever the trip parameters are changed.

Abstract: The disclosed faulted current indicator senses current in a line having a breaker or fuse, and avoids tripping in response to current inrush signals by producing a trip signal in response to an overcurrent occurring for an overcurrent duration which is inversely related to the magnitude of the overcurrent and is faster than the overcurrent operating time of the breaker or fuse. In one embodiment, this involves operating a current protection device in response to an overcurrent occurring for a second overcurrent duration inversely related to the magnitude of the overcurrent according to a first characteristic, and adjusting the first overcurrent duration to follow a second characteristic having variations substantially the same as the first characteristic but having a shorter first overcurrent duration than the second overcurrent duration.

Abstract: An automatic override circuit is responsive to the magnitude of instantaneous current flow through a monitored conductor to produce an output signal which can actuate a solenoid or a ground fault interrupter to automatically trip a circuit breaker in repsonse to an excursion of current flow which exceeds a predetermined maximum current overhead level. The short circuit protector can automatically override a thermal trip delay and cause the circuit breaker to trip instantly or delay tripping for a prescribed period of short circuit events which exceed the maximum current overload level. In one embodiment, a control signal is generated which actuates a solenoid which is coupled to a thermal magnetic circuit breaker. In an alternative embodiment, the control signal is utilized for automatically triggering a ground fault interrupter.