Abstract: A fast-operating AC fault current limiter, to limit the fault current let through to downstream equipment during short circuit or low-impedance faults, comprises a series inductor to limit current rise time, a current sensor to sense the instantaneous current, a series AC semiconductor switch to interrupt current flow when it exceeds the maximum desired fault current, and a shunt AC semiconductor switch to catch inductor flyback voltage when the series semiconductor switch is opened. Each of the series and the shunt AC switches comprises two back-to-back MOSFETs. Inventive control of timing of the individual MOSFETs obviates the need for exact simultaneous timing of opening the series switch and closing the shunt switch, which is otherwise required to avoid short circuits.

Abstract: A DC to AC converter is described in which DC power presented as a set of relatively floating DC power sources of differing DC voltage values is converted to a desired AC power waveform by combining the DC voltage values with sequential sets of associated ternary-valued multiplicative weights of +1, ?1, or 0, and summing the weighted voltage values, so as to produce voltage points on the desired waveform at appropriate time instants.

Abstract: A safety shut-down system for a solar energy installation includes a DC to AC inverter converting DC power from a photovoltaic solar array to AC power and generating remote control signals to enable or disable the flow of DC power from each individual photovoltaic panel or string of panels to a photovoltaic output circuit. One or more manual switches, one of which may be at a service entrance for electrical power to the installation, are operative to cause the DC to AC inverter to disable all DC power from the photovoltaic solar array; this also occurs when the DC to AC inverter is shut off. A storage battery may selectively receive DC power from one or more photovoltaic panels or strings of panels for charging. The DC to AC inverter may generate AC power from the battery when the photovoltaic solar array is disabled.

Abstract: A smart load center panel (10) accepts two hot legs from each of two power sources, and selectively connects each of a plurality of breakers to one of the two power sources under processor control. A dielectric chassis (12) provides structural support and electrical isolation for a plurality of individual circuit boards (28), each including a pair of breaker stabs (26) and a relay (24) operative to selectively connect each breaker stab (26) to a different power source. A bus bar assembly (20) comprises two bus bars for the hot legs of each of two power sources, and insulates the bus bars from each other and from inadvertent contact. A master printed circuit board (40) comprises slits (43, 45) defining the individual circuit board (28) except at the edges. After mounting and soldering, the edges are cut away, yielding a plurality of individual circuit boards (28). Neutral and ground bus bars (46, 52) are mounted to the side of the panel housing (12), behind a flange of a front opening.

Abstract: A safety shut-down system for a solar energy installation includes a DC to AC inverter converting DC power from a photovoltaic solar array to AC power and generating remote control signals to enable or disable the flow of DC power from each individual photovoltaic panel or string of panels to a photovoltaic output circuit. One or more manual switches, one of which may be at a service entrance for electrical power to the installation, are operative to cause the DC to AC inverter to disable all DC power from the photovoltaic solar array; this also occurs when the DC to AC inverter is shut off. A storage battery may selectively receive DC power from one or more photovoltaic panels or strings of panels for charging. The DC to AC inverter may generate AC power from the battery when the photovoltaic solar array is disabled.

Abstract: A single- or multi-phase DC to AC converter system suited for solar energy installations achieves cost reduction by eliminating low-frequency power transformers. One DC input polarity is selectively switched to an output terminal when the instantaneous AC output from a second output terminal is desired to be of the opposite polarity, while the other DC input polarity is used to form an approximation to a segment of a sine wave of the desired polarity at the second output terminal. The approximation for each phase is built in a multilevel fashion by outputting, at different times, voltage levels that differ by an integer multiple of a predetermined voltage step size, to the respective live AC output terminal through an associated low pass filter. A common-mode AC signal is thereby created on the balanced DC input lines at a frequency which is the AC output frequency times the number of phases, and which is useful for detecting ground faults in the DC circuit.

Abstract: A communications system is described providing the ability to intelligently deliver electrical power from a first power source or from a second power source to a branch circuit in a facility, such as a home. Communications between a Smart Load Center (SLC) controller and the appliances is provided via a combination of signals sent over the electrical wiring and signals sent over the air. In particular, the signals over the electrical wiring serve to identify to which branch circuit the appliance is connected. The signals over the air support the communications between the appliances and the SLC controller, and may be part of a larger Internet-of-Things ecosystem dedicated to facilities automation services.

Abstract: The selection of electrical power supplied to a load, between a first power source such as the electric utility grid, and a second power source such as a solar-charged battery-inverter system, is made at the granularity of individual electrical outlets (or junction boxes for appliances directly connected or loads installed as fixtures). A central controller determines the power source for each outlet, based on numerous factors including the current consumed by that outlet's load(s). The controller addresses power selection commands to each outlet. Each outlet includes a SPDT functionality switch that operates in response to the controller to connect loads to a line conductor from the first power source or a line conductor from the second power source. A common neutral conductor connects to both sources. The outlets include current monitoring, and may include GFCI and/or AFCI protection. A variety of power distribution panel configurations and wiring options are disclosed.

Abstract: In an electrical distribution system for a facility served by two power sources, ground currents on neutral conductors are avoided by utilizing a common neutral conductor in distributing power from both power sources to one or more transfer switches. In at least one single cable or conduit run, either between transfer switches or between both power sources and a transfer switch, line conductors carry power from each power source to the transfer switch(es), and a common neutral conductor carries return current for both power sources. The neutral terminals of both power sources are connected together (in part via the common neutral conductor in the single cable or conduit run), and the common neutral is grounded at only one place.

Abstract: Systems and method relating to machining parts include a CNC system, and a computer including a processor and a computer-readable medium, wherein the computer-readable medium encodes instructions including receiving, at the computer program, output data from a CNC machine that receives instructions of a Numerical Control (NC) program at a computer of the CNC machine, the instructions causing the CNC machine to i) manufacture a part, and ii) output the output data, parsing, by the computer program, the output data before completion of the manufacturing of the part by the CNC machine in accordance with the instructions of the NC program, selecting, by the computer program and based on one or more predetermined parameters, a set of data from the parsed output data; and providing, by the computer program to a remote system, the set of data for processing to facilitate machining using the CNC machine.

Abstract: A communications system is described providing the ability to intelligently deliver electrical power from a first power source or from a second power source to a branch circuit in a facility, such as a home. Communications between a Smart Load Center (SLC) controller and the appliances is provided via a combination of signals sent over the electrical wiring and signals sent over the air. In particular, the signals over the electrical wiring serve to identify to which branch circuit the appliance is connected. The signals over the air support the communications between the appliances and the SLC controller, and may be part of a larger Internet-of-Things ecosystem dedicated to facilities automation services.

Abstract: A safety shut-down system for a solar energy installation includes a DC to AC inverter converting DC power from a photovoltaic solar array to AC power and generating remote control signals to enable or disable the flow of DC power from each individual photovoltaic panel or string of panels to a photovoltaic output circuit. One or more manual switches, one of which may be at a service entrance for electrical power to the installation, are operative to cause the DC to AC inverter to disable all DC power from the photovoltaic solar array; this also occurs when the DC to AC inverter is shut off. A storage battery may selectively receive DC power from one or more photovoltaic panels or strings of panels for charging. The DC to AC inverter may generate AC power from the battery when the photovoltaic solar array is disabled.

Abstract: Process for making a fabric label (1) containing one piece of unique electronically-readable information; characterized by comprising the following steps: providing a fabric bolt made of a material mainly comprising synthetic fibers at least in the weft, generating at least one array of m×n cells, being n the number of rows and m the number of columns; generating at least one first sequence of variable information (3); associating the variable information (3) to the cells of the previous array in compliance with a predetermined logic; inserting, by the use of an image assembler, the graphic form that can be associated with each of said variable information (3) into a cell of a graphics array (5) with size m×n; printing said array (5) of images on a first medium (8) through a digital printing process; transferring said print, by heating, through a process named sublimation on said bolt (7) to generate a second medium (9) of fabric comprising said array (5); storing in a database the variable information (3) pr

Abstract: A transformerless DC to AC inverter providing an AC output at a power line voltage and at a power line frequency suitable for driving AC loads or appliances and having DC bias measurement circuitry for continuously assessing the magnitude of any DC bias component on the AC output, such as due to fault conditions or non-linear loads, and operative to eliminate or reduce any unwanted DC bias component from the AC output.

Abstract: Sharing of load current in desired ratios between multiple electrical voltage sources is achieved without coupling between the sources by controlling a selection switch to select each voltage source for a proportion of the time at a high rate, the switching rate components being prevented from being seen by either the load or the sources through use of low-pass filters.

Abstract: An electrical measurement device for monitoring the current and power taken by a plurality of electrical loads that may be powered by a selected one of multiple AC power sources comprises sampling the voltage of said sources and the current taken by said loads at a integral number of samples per cycle at sample times determined by an independent processor clock. The integral number of samples of each measured parameter for each cycle are processed to determine a complex number for each parameter representative of the amplitude and the phase relative to the independent processor clock. The phase drift of the substantially constant source voltages may be determined as a measure of frequency of the sources, and may be used to cancel drift of the current measurement to enable averaging.

Abstract: A transformerless DC to AC inverter providing an AC output at a power line voltage and at a power line frequency suitable for driving AC loads or appliances and having DC bias measurement circuitry for continuously assessing the magnitude of any DC bias component on the AC output, such as due to fault conditions or non-linear loads, and operative to eliminate or reduce any unwanted DC bias component from the AC output.

Abstract: An electrical installation having a first source of power, such as the utility grid, and a second source of power from an electronic DC-to-AC converter, comprises a smart load center for selecting the source of power independently for each of a number of branch circuits protected by circuit breakers to be the first source or the second source. The smart load center comprises a software-controlled processor for operating the transfer relays that select the first or second source of power for each branch circuit. In the event that a current overload on a branch circuit connected to the DC-to-AC converter causes it to trip before the branch circuit breaker clears the overload, all circuits are transferred to the first power source to trip the fault breaker and then the microprocessor enters a restart sequence to verify that the fault is cleared or else to take other action.

Abstract: A remote-controlled photovoltaic string combiner is described that selects strings to be combined to a first photovoltaic output circuit or to a second photovoltaic output for the purpose of either controlling the charging of a battery connected to the first photovoltaic output circuit or for diverting current to a diversion load such as a grid-tie inverter. Strings are selected by energizing relays from one or other inverter such that when neither inverter is operating, all strings are deselected and both photovoltaic output circuits are de-energized.

Abstract: Systems and method relating to machining parts include a CNC system, and a computer including a processor and a computer-readable medium, wherein the computer-readable medium encodes instructions including receiving, at the computer program, output data from a CNC machine that receives instructions of a Numerical Control (NC) program at a computer of the CNC machine, the instructions causing the CNC machine to i) manufacture a part, and ii) output the output data, parsing, by the computer program, the output data before completion of the manufacturing of the part by the CNC machine in accordance with the instructions of the NC program, selecting, by the computer program and based on one or more predetermined parameters, a set of data from the parsed output data; and providing, by the computer program to a remote system, the set of data for processing to facilitate machining using the CNC machine.