Abstract: A lighting control system is provided for a space that is equipped with multiple lamps for illuminating the space and multiple power circuits for supplying power to different groups of the lamps. The control system stores information relating to the past illumination of the lamps in each of the different groups. The system detects conditions or events that indicate that increased illumination of the space by the lamps is needed, and produces a control signal in response to the detection of a condition or event that indicates that increased illumination of the space by the lamps is needed. In response to the control signal, the system supplies power to at least one of the power circuits, which is selected on the basis of the stored information, to turn ON the group of lamps receiving electrical power from that power circuit.

Abstract: An algorithm for verifying the state of switches (such as in a transfer switch mechanism) and for controlling the switches. The control algorithm controls automatic actuation of the switches. The verification algorithm measures the instantaneous voltage on the source and load sides of one or both switches and calculates the RMS magnitude, period, and relative phase for each voltage measurement. If the voltage characteristics for the load do not match any of those for any source, an error is outputted. If the voltage characteristics of the sources match each other, the algorithm determines that they are synchronized. The algorithm determines which switch is closed by comparing the voltage characteristics of the load and of each source, and if there is a match, then the switch associated with the source that is matched with the load is determined to be closed. Otherwise, the switch is determined to be opened.

Abstract: A method of monitoring the electrical power in multiple branch circuits of an AC electrical power distribution system comprises monitoring at least one voltage common to said multiple branch circuits using a main meter unit, monitoring currents of the multiple branch circuits using multiple current cards that receive a plurality of current inputs from current transducers in the multiple branch circuits, sampling the monitored voltage in the main meter unit and the monitored currents in the current cards multiple times in each cycle of the AC power signal, determining the magnitudes and angles of spectral components of the sampled current in the current cards, sending data representing the magnitudes and angles of at least selected spectral components from the current cards to the main meter unit, and storing the voltage samples and the magnitudes and angles of at least the selected spectral components in the main meter unit.

Abstract: An electrical enclosure system for transferring heat from a closed environment, includes an electrical device having a heat-generating part, and a polymer-based ventless housing for protecting the electrical device from environmental contaminants. The ventless housing fully encloses the electrical device and includes a base layer forming an impact-resistant portion of the ventless housing. The base layer includes one or more open areas in close proximity to the heat-generating part. The ventless housing further includes an integrated thermally conductive layer that forms a heat-flow path for conducting heat away from the heat-generating part towards an exterior environment. The integrated thermally conductive layer is molded around the base layer such that portions of the integrated thermally conductive layer cover the open areas of the base layer.

Abstract: A method of performing a sequence-of-events analysis in a power monitoring system includes the acts of monitoring, receiving, analyzing, and storing. The act of monitoring includes monitoring messages published by multiple power monitors over a peer-to-peer communications network. The messages include electrical power monitoring parameters. The act of receiving includes receiving the published messages in a subscriber intelligent electronic device in the power monitoring system. The act of analyzing includes analyzing at least a portion of the received messages, performing statistical analysis and/or continuously scanning for an event of interest. The act of storing includes storing at least one record including at least one of statistical data or event of interest data.

Abstract: A method of graphically representing values of at least one selected parameter at multiple monitoring points in a utility system, comprises receiving data measured at the multiple monitoring points; determining the values of the selected parameter at the multiple monitoring points, based on the received data, and using the values to generate a graphical representation of the values of the selected parameter at the multiple monitoring points, the graphical representation including shapes having (1) sizes representative of the magnitudes of the values and (2) locations representative of the hierarchy of the monitoring points. In one application, the selected parameter is at least one of electrical power and energy consumed in portions of an electrical power distribution system that correspond to the multiple monitoring points.

Abstract: A communication system is provided for communication within a control system. The communication system has a plurality of simple devices connected to an intra-level communications network, each simple device being adapted to directly exchange data with the other simple devices. The communications system also has at least one intelligent device connected to the intra-level communications network, each intelligent device being adapted to directly exchange data with each simple device on the intra-level communications network. The communication system can have a plurality of intra-level communications networks.

Abstract: Circuit for determining the presence or absence of a remotely controlled circuit beaker connection to a control circuit and the current state of an internal operating device of a remotely controlled circuit breaker connected to a control circuit.

Abstract: An induction motor having a rotor and a stator is protected during running overloads by connecting the motor to an overload protection relay that can be tripped to interrupt power to the motor in the event of an overload, tracking the stator winding temperature of the motor during running overloads with a hybrid thermal model by online adjustment in the hybrid thermal model, and tripping the overload protection relay in response to a predetermined running overload condition represented by the tracked stator winding temperature. In one embodiment of the invention, the stator winding temperature is tracked by use of an online hybrid thermal model that uses the resistance of the rotor as an indicator of rotor temperature and thus of the thermal operating conditions of the motor. The hybrid thermal model incorporates rotor losses and heat transfer between the rotor and the stator, and approximates the thermal characteristics of the rotor and stator.

Abstract: A DC motor mechanical shock protection system monitors the motor current to determine the torque the motor is applying to the gearbox, and takes mitigating action if the torque approaches a level that can damage the driven device and/or the drive system. This protects the system from mechanical shock without limiting the available torque during normal operation. The change in motor current is monitored to detect the inertial torque before the elasticity between the motor and the driven device is fully compressed and the motor mounting or gearbox begin to be damaged.

Abstract: A controller for an automatic transfer switch mechanism in an electrical distribution panel, which automatically determines motor phase by monitoring the back EMF voltage of the motor when no power is applied to the motor as defined by a pulse width modulation circuit. Phase comparisons of the voltage on the line and load sides of the transfer switch mechanism determine the position of the transfer switch mechanism.

Abstract: A DC motor phase detection algorithm that monitors the change in motor current to detect pulses in the current caused by the motor's commutator brushes crossing over the gap between rotor commutator segments as the motor shaft rotates. A pulse is generated each time a commutator brush breaks and then reconnects to a commutator segment. The algorithm detects and counts the pulses in order to determine the number of revolutions the shaft has rotated. The motor phase can then be used to determine the distance, rotational or linear, that the moving portion of the load attached to the motor has traveled. If the initial position of the moving portion of the device is known then the absolute position can be calculated.

Abstract: Apparatus for providing an accelerated linear motion to a circuit breaker operating handle during ON or OFF operation of the circuit breaker. The accelerated linear motion being applied to the operating handle at a particular point during its movement such that the moveable contacts of the circuit breaker are not delayed in their opening or closing due to slow movement of the circuit breaker operating handle.

Abstract: A circuit breaker includes a breaker enclosure, a plurality of conductor connections, and a temperature sensor. The breaker enclosure contains internal components that include a trip unit. The plurality of conductor connections electrically couple the trip unit to a plurality of power conductors. The temperature sensor is located to sense heat radiated by the conductor connections and is positioned inside the enclosure.

Abstract: A method and system to detect and evaluate harmonic distortion in an electrical power system is disclosed. A plurality of monitoring devices is installed in the electrical power system. The hierarchy of the electrical power system is received. Data indicative of harmonic distortion on the electrical power system is received from at least two of the monitoring devices. The data indicative of harmonic distortion is automatically aligned in a temporal or pseudo-temporal context. An electrical characteristic of the harmonic distortion from the data indicative of harmonic distortion is determined.

Abstract: A digital power metering system reduces spectral leakage when determining the frequencies present in a power signal by a technique that includes sampling the signal and performing a transformation from the time domain to the frequency domain. The system initially measures the fundamental frequency of the power signal, and samples the power signal at a known sampling rate to produce digital sample values representing the power signal. The system then determines whether the known sampling rate is within a preselected range of a rate that is coherent with the measured fundamental frequency. If the answer is negative, then the system resamples the signal at a rate that is coherent with the measured fundamental frequency to produce resample values representing the signal, so that the frequencies present in the power signal can be determined from the resample values.

Abstract: A DC motor phase estimation algorithm that estimates a speed-related harmonic frequency of a DC motor current under dynamic load conditions having known geometry parameters. The algorithm estimates the phase and magnitude of a complex coefficient in a complex single frequency adaptive filter that receives a primary signal from the motor current and estimates a reference signal using an incident frequency by adapting the complex coefficient to match the magnitude and phase of the speed-related harmonic component of the primary signal. The rate of change of the phase of the complex coefficient is determined by a phase-lock loop coupled to the adaptive filter to adapt a dynamic incident frequency corresponding to a single frequency component of interest in the primary signal. The incident frequency is extracted, and the motor speed is estimated using the extracted incident frequency and the known motor geometry parameters.

Abstract: A trip unit in a miniature circuit breaker includes a magnetic yoke and a bimetal mounted on the outside of the yoke. The bimetal is welded at one end to a load terminal that leads to a terminal connector and at the other end to a pigtail. The pigtail, instead of the bimetal, passes through the yoke for connection to the blade of the circuit breaker. To induce a higher magnetic field for faster tripping, a second pigtail may be passed through the yoke in which one end of the second pigtail is connected to the load terminal near the terminal connector and the other end is connected to the bimetal near the load terminal connection point. The load terminal may include at least two parts, one part including the adjustment screw and the other part including the terminal screw. These parts may be separated by air or an insulator.

Abstract: A circuit breaker lock-off device is side-mounted to a circuit breaker case in a tenacious engagement. The lock-off device has a generally planar body carrying a lock-off arm pivotable in a plane parallel to the body to place an engagement tab extending therefrom into a position for preventing movement of the breaker handle without being physically attached to the breaker handle. The lock-off arm and the body further have complementary rings for accepting a padlock shackle in the locked off position. The invention allows a rugged lock-off accessory which is field installable and which can accommodate various breaker handle geometries.

Abstract: An automated integrated monitoring (IM) algorithm that automatically puts data from a utility monitoring system into context by temporally aligning the data to a common reference point and by identifying the location of each monitoring device in a hierarchy relative to other devices. Frequency variation data is received from all meters. The data is automatically aligned to a common reference point, such as a precise zero crossing, using a cross-correlation algorithm to determine the time delay at which the data is most correlated. Once the data is aligned, power data is received from all meters in a hierarchy, and the monitoring system layout is auto-learned using a correlation algorithm to determine which two meters are most likely correlated with one another based upon their historical power readings. Once the layout is complete, additional decisions regarding hardware and software configuration can automatically be made by the IM algorithm.