Abstract:
A ground fault circuit breaker is provided which includes means for sensing ground fault current and for analyzing the waveform of the ground fault current. An operating mechanism automatically separates the contacts of the circuit breaker upon detection of ground fault current waveforms corresponding to the waveform of current passing through human skin. In a preferred embodiment, means are provided to synchronously detect the third harmonic component of ground fault current using phase and amplitude information to determine the presence of a ground fault path through human skin. Alternatively, means are provided to sense peak and average values of ground fault current and to trip the breaker whenever the ratio of peak to average ground fault current exceeds a predetermined level. In another alternative, the slope of the ground fault current at zero crossing is detected and compared to the ground fault current peaks. Whenever the ratio of peak current to zero crossing slope exceeds a predetermined level, the mechanism of the breaker is tripped.
Abstract:
A cylindrical, elongated incandescent lamp is positioned within a tubular light reflecting member including a line light diffuser strip window. The light reflecting member responds to the electrical excitation of the incandescent lamp by emitting a light pattern through the line light diffuser strip window.
Abstract:
A releasable net system using a releasable net attachment mechanism is provided. The releasable net system includes two or more upright structures with lateral support structures extending therebetween, and at least one net configured with the lateral support structures to form a net wall. The at least one net is attached to the lateral support structures using one or more releasable attachment mechanisms that are adapted to break under a predetermined load. In this way, the releasable attachment mechanisms may release the net from the support structures under environmental load conditions (high winds, snow, freezing rain) prior to the collapse of the support structures. The system may be used with outdoor netting systems such as those used for errant ball containment at golf driving ranges.
Abstract:
A circuit breaker includes separable contacts; a load conductor; a neutral conductor; and an operating mechanism structured to open and close the separable contacts. An arc fault trip circuit cooperates with the operating mechanism and trips open the separable contacts responsive to detection of an arc fault condition associated with current flowing through the separable contacts. A ground fault trip circuit cooperates with the operating mechanism and is structured to trip open the separable contacts responsive to detection of a ground fault condition associated with current flowing through the separable contacts, the load conductor and the neutral conductor. The arc fault trip circuit includes an integration capacitor, and the ground fault trip circuit includes an output to the integration capacitor.
Abstract:
A trip unit for a circuit interrupter includes a power supply, a plurality of input terminals and a plurality of output terminals. A heater conductor is electrically connected between each pair of the input and output terminals. The heater conductor is adapted to generate heat responsive to current flowing through the conductor. A diode is disposed proximate each of the conductors for heating thereby. The diodes are electrically interconnected with the power supply and are adapted to provide a forward voltage representative of the temperature of the corresponding conductor. Another diode is electrically interconnected with the power supply and is adapted to provide a forward voltage representative of ambient temperature. A thermal trip circuit generates a trip signal for the circuit interrupter responsive to the forward voltage of the diodes.
Abstract:
A network protector is provided with diagnostics which alert a utility of component problems in detail. Selected measurements are used to assess the condition of various components such as for example, main contact electrical resistance, a blown fuse, the availability of sufficient voltage for charging the springs which close the main contacts and adequate voltage for tripping the contacts open. These abnormal operating conditions are transmitted to a remote station at the utility so that proper maintenance can be efficiently provided.
Abstract:
A circuit breaker responds to sputtering arc faults by counting the times that a bandwidth limited di/dt signal exceeds a threshold magnitude within a selected time interval. In the exemplary circuit breaker, if the threshold is exceeded twice within a one second interval, a trip solenoid is energized. The di/dt sensor can share a sensing coil with a ground fault detector. Alternatively, the resistance of the neutral lead within the circuit breaker is utilized to sense current which is converted to a bandwidth limited di/dt signal for level detection and counting of sputtering arc events.
Abstract:
A panelboard for power lines and loads includes a housing; a plurality of circuit breakers housed by the housing; and a panelboard controller substantially housed by the housing. Some of the circuit breakers, which switch a circuit from one or more of the power lines to the loads, include remotely controllable actuating circuits for actuating the circuit breakers and switching a circuit from one or more of the power lines to one or more of the loads. The panelboard controller includes a monitoring circuit for monitoring power or energy consumed in the circuits of the circuit breakers and a control circuit for controlling the remotely controllable actuating circuits.
Abstract:
In a ground fault circuit interrupter in which it was found that wide band noise induced by load transients is rectified by an op-amp in the detector circuit, false trips due to the wide band noise are eliminated by only comparing the output of the amplifier with a threshold of opposite polarity to that of the rectified noise signal and by eliminating capacitive coupling between the current sensor and the op amp. This requires an op amp with a low offset, on the order of about five percent or less.
Abstract:
A PC computer monitors the energy consumed at a plurality of local stations placed behind the electrical meter of the utility company for individual billing of the local users, a bidirectional communication line being used therebetween. A command from the PC computer causes at each station the totalized energy to be stored, and thereafter the PC computer derives individually the results for separate estimations and central billing.