Abstract: A virtual branch circuit system for an electric vehicle supply equipment (EVSE) can include a current sensor disposed in operative communication with circuit wires of a plurality of circuits of a virtual branch. The current sensor can be disposed between a plurality of circuit breakers and a plurality of respective loads. At least one of the plurality of loads is not an EVSE. The current sensor can be configured to sense a virtual branch total current comprising total current of all non-EVSE loads on the virtual branch. The system can include a control module operatively connected to the EVSE and configured to control a maximum EVSE current based on the virtual branch total current to maintain the virtual branch total current at or under a maximum branch current threshold.

Abstract: In an electrical distribution system having an arc management system for removal of arcing voltage from feeder circuits triggered at least in part by light signals, a secondary optical detector monitors a downstream branch circuit breaker in the feeder circuit compartment to produce an optical signal for arc detection more accurately reflecting the possibility of an arcing fault.

Abstract: In an electrical distribution system having an arc management system for removal of arcing voltage from feeder circuits triggered at least in part by light signals, a secondary optical detector monitors a downstream branch circuit breaker in the feeder circuit compartment to produce an optical signal for arc detection more accurately reflecting the possibility of an arcing fault.

Abstract: A method and apparatus for composing a desirable trip curve, such as an I2*t trip curve, for an electrical protective device from at least one less desirable trip curve, such as an I*t trip curve. The method is accomplished by defining a selected parameter of the desirable overload trip curve and defining the selected parameter as a function of one or more monitored input values, such as current, trip class or phase unbalance, and modulating the selected defined parameter value between a maximum boundary trip curve and a minimum boundary trip curve. The modulated parameter is used to adjust the less desirable trip curve such that it has the characteristics of the desired trip curve. The method is implemented by one or more electrical circuits (filter circuits) representing the less desirable trip curve(s) and composing an output signal representing the desirable trip curve by modulating between the one or more electrical circuits.

Abstract: A method and apparatus for composing a desirable trip curve, such as an I2*t trip curve, for an electrical protective device from at least one less desirable trip curve, such as an I*t trip curve. The method is accomplished by defining a selected parameter of the desirable overload trip curve and defining the selected parameter as a function of one or more monitored input values, such as current, trip class or phase unbalance, and modulating the selected defined parameter value between a maximum boundary trip curve and a minimum boundary trip curve. The modulated parameter is used to adjust the less desirable trip curve such that it has the characteristics of the desired trip curve. The method is implemented by one or more electrical circuits (filter circuits) representing the less desirable trip curve(s) and composing an output signal representing the desirable trip curve by modulating between the one or more electrical circuits.

Abstract: An economical digital voltage sag compensator for overcoming sags in distributed electrical power. The voltage sag compensator employs an inexpensive micro-controller, a full wave bridge rectifier, a DC power supply, a voltage divider and an output switch. The micro-controller continuously monitors and evaluates, with respect to a setpoint measured in volt-seconds, the rectified DC voltage. At regularly spaced trigger events, as determined by the micro-controller, the micro-controller concurrently monitors the rectified DC voltage, evaluates the monitored voltage with respect to the setpoint, produces an output signal and sends that output signal to the output switch. The output switch supplies an electrical device, connected electrically in series with the full wave bridge rectifier and the output switch, with a constant average current of sufficient level to maintain the electrical device in a desired operating condition.

Abstract: An economical digital voltage sag compensator for overcoming sags in distributed electrical power. The voltage sag compensator employs an inexpensive micro-controller, a full wave bridge rectifier, a DC power supply, a voltage divider and an output switch. The micro-controller continuously monitors and evaluates, with respect to a setpoint measured in volt-seconds, the rectified DC voltage. At regularly spaced trigger events, as determined by the micro-controller, the micro-controller concurrently monitors the rectified DC voltage, evaluates the monitored voltage with respect to the setpoint, produces an output signal and sends that output signal to the output switch. The output switch supplies an electrical device, connected electrically in series with the full wave bridge rectifier and the output switch, with a constant average current of sufficient level to maintain the electrical device in a desired operating condition.

Abstract: The present invention discloses an improved arc fault detection circuit comprising a light detector for generating a light detector signal, a differentiator circuit for receiving a light detector signal and creating a differentiated light detector signal, and a comparator circuit for comparing the differentiated light detector signal and a reference signal and generating a comparator output signal for indicating when the differentiated light detector signal exceeds the reference signal.

Abstract: A solenoid operated remote resetting device with a protective solenoid activation circuit is disclosed. The device includes a housing for enclosing and protecting a solenoid with a movable plunger, a movable mechanical operator having an operator arm extending through an opening defined in the housing and a circuit board on which a solenoid activation circuit is mounted. The solenoid activation circuit includes circuitry for protecting the solenoid from overheating due to intentional or unintentional prolonged current flow in the solenoid.

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 data error detection method for a bit, byte or word oriented network wherein a protected data unit 46 and an associated data check unit 50 are addressed to a particular field device located on the network, 10 or 26. The data check unit 50 is derived in a particular manner either solely from the protected data unit 46 or from the protected data unit 46 and particular binary codes representing attributes of the network 10 or 26 and the field device sending the protected data unit 46. The particular configuration of the checking data unit 50 is such that the receiving field device or the host 22 can perform a bit-by-bit comparison of either the received protected data unit 46 or data check unit 50 with a protected data unit 46 or data check unit 50 derived in the particular manner by the receiving host 22 or field device 14 or 18.

Abstract: A solenoid operated remote resetting device with a protective solenoid activation circuit is disclosed. The solenoid activation circuit includes circuitry for protecting the solenoid from overheating due to intentional or unintentional prolonged current flow in the solenoid. The solenoid activation circuit receives an activation signal, in the form of an alternating current signal, from a remote activation means. The activation signal is coupled to a rectifier in the solenoid activation circuit that provides rectified DC power for the solenoid activation circuit. A solenoid power circuit is also coupled to the rectifier input such that the AC signal from the activation means can be rectified and passed to the solenoid positive DC signal. A timing circuit coupled between the rectifier output and the solenoid power circuit provides an active phase of a predetermined time and a blocking phase after each application of the activation signal.

Abstract: A current induction arrangement develops a power supply voltage and a measurement signal from current flowing in a circuit path so as to optimize both the energy developed in the power supply and the fidelity of the sinusoidal signal used to measure the waveform in the circuit path. The arrangement includes a capacitor accumulating current to develop a positive voltage with respect to common, a current transformer inducing current from the circuit path and providing an output having a positive induced-current signal component and a negative induced-current signal component. A rectifier circuit is arranged to receive the output from the current transformer, and to produce the positive induced current signal component at a positive output terminal and the negative induced current signal component at a negative output terminal. A first zener diode is connected to receive the positive induced-current signal component, and the circuit permits the positive induced-current signal to charge the capacitor.

Abstract: A calibration method for a potentiometer which provides indicia reflecting an accurate indication of actual electrical resistance throughout the resistive range of a particular potentiometer. The indicia includes a number of graduation marks or symbols having a range and spacing unique to the resistive characteristics of the particular potentiometer. The indicia is fixed with respect to a known location associated with the particular potentiometer. The range and spacing of the indicia graduations is derived from measured resistance values at predetermined locations along the resistive member of the particular potentiometer.

Abstract: A solid state overload relay utilizes an apparatus that converts the current of a polyphase electrical load to a voltage signal approximately proportional to the RMS current of the load. In addition to providing the overload function, the voltage signal is used to provide an improved phase current unbalance protection. Conventional current transformers sense the current flow in each phase of the load. The current waveform for each phase is converted to a voltage by rectification and the peak value and the average value of the resultant voltage is determined. A summing circuit combines the two values at a predetermined ratio to create a DC voltage that is approximately equal to the rms value of the input phase current. A combination of the approximation circuit with a time integrating circuit and a level detecting circuit produces a low cost solid state overload relay in one embodiment of the invention.

Abstract: A method and apparatus provides for a measurement technique which approximates the true rms value of a current waveform. The technique involves converting the current waveform to a voltage by rectification and determining the peak value and the average value of the resultant voltage. A summing circuit combines the two values at a predetermined ratio to create a DC voltage that is approximately equal to the rms value of the input currents. The DC voltage output is suitable for a wide range of applications. A combination of the approximation circuit with a time integrating circuit and a level detecting circuit produces a low cost solid state overload relay in a preferred embodiment of the invention. Other uses include metering and use as a current feedback control signal for controlling PWM inverters and the like.