In some embodiments, a controller of an intelligent switch in a three-phase power distribution network is configured to serve as a sectionalizer. The controller preferably includes voltage restraint logic and count restraint logic to prevent opening of the switch in response to a detected fault unless the voltage and current drop below minimum threshold values. The controller preferably additionally includes inrush restraint logic that prevents detection of a fault in response to an inrush current spike that may occur, for example, on startup of an AC motor or when energizing a transformer. The controller preferably further includes close-on-fault detection logic that bypasses counting of fault/line clear events by the controller if the switch is closed on a fault.

The invention relates to a control circuit for protecting an electrostatic spray-coating apparatus, which has a high-voltage supply, against spark discharge. The control circuit has a disconnection device for automatically disconnecting the high-voltage supply, and has a device for detecting abnormal operation of the high-voltage supply. The device for detecting abnormal operation of the high-voltage supply is designed to monitor at least one parameter which is characteristic of the operation of the high-voltage supply, and to output a corresponding disconnection signal to the disconnection device when the at least one parameter which is characteristic of the operation of the high-voltage supply exceeds or falls below a predefined or predefinable limit value.

An apparatus and method for minimizing inrush power. The method includes transmitting a load energization signal from a primary microcontroller to a logic latch or secondary microcontroller, transmitting a zero-cross voltage signal from a zero-cross sensor coupled to the load power to the logic latch or secondary microcontroller, and transmitting an energize signal from the logic latch or secondary microcontroller to a relay after the receipt of an energize signal from the primary microcontroller and after receipt of a zero-cross signal.

The present disclosure relates to a power distribution unit (PDU) having at least one power receptacle for enabling attachment of an AC power cord of an external device thereto. A branch receptacle controller (BRC) has at least one bistable relay and is associated with the one power receptacle for supplying AC power thereto from an AC power source. The BRC monitors a voltage of an external power source and uses it to detect when AC power is lost, and then toggles the bistable relay, if the relay is in a closed position, to an open position.

Unique systems, methods, techniques and apparatuses of inrush current detection and reduction are disclosed. One exemplary embodiment is a method for transmitting power to a load comprising operating a solid-state switching device of a power distribution network device with a microcontroller-based controller, the solid-state switching device including a gate and structured to receive a signal with the gate so as to control the switching device to receive power from a power source and selectively provide power including an output current to the load; detecting an overcurrent condition in the output current; operating the solid-state switching device in order to determine the load is a capacitive load in a charging condition in response to detecting an overcurrent condition; and operating the solid-state switching device so as to reduce the magnitude of the output current during the charging condition.

Provided is a premagnetization device for a converter system that is connectable to a three-phase electrical grid that has a three-phase power transformer, a converter connected to the power transformer and a circuit-breaker on the grid side of the power transformer. The premagnetization device is premagnetizes the power transformer in a state isolated from the grid. The premagnetization device uses a single-phase reference voltage (Uref) that has a fixed relationship to the grid voltage (Ugrid) with regard to the voltage parameters, in order to generate, based on the measured instantaneous reference voltage (Uref) and the known fixed parameter relationships, by actuating the converter, a three-phase alternating voltage synchronous to the grid voltage (Ugrid) on the grid side of the power transformer.

A system for reducing inrush current to an electronic component, the system including: a power supply, the power supply providing power at multiple nonzero voltages; and the electronic component; wherein, when the electronic component is connected to the power supply, the power supply provides a first non-zero voltage to the electronic component and, in response to a signal from the electronic component, provides a second voltage, the second voltage being higher than the first voltage, to the electronic component.

A wiring device including an interrupting device, a fault detection device, and a controller. The interrupting device is configured to place the wiring device in a tripped condition in which the flow of power between one or more line terminals and one or more load terminals is interrupted. The fault detection circuit is configured to detect a fault condition and generate a fault detection signal in response to detecting the fault condition, the fault detection signal being provided to the interrupting device to place the interrupting device in the tripped condition. The controller is configured to monitor a current of the one or more line terminals, identify a presence of an in-rush condition or a steady-state condition, and prevent the output of the fault detection signal upon identifying either the in-rush condition or the steady-state condition.

A wiring device including an interrupting device and a controller. The interrupting device electrically connecting one or more line terminals to one or more load terminals when the interrupting device is in a reset condition and disconnecting the line terminals from the load terminals when the interrupting device is in a tripped condition. The controller has an electronic processor and a memory. The controller is configured to monitor a current of the one or more line terminals, identify a presence of an in-rush condition, wherein an in-rush of the current exists when the one or more cycles of current conform with a decay progression envelope, and prevent the tripped condition upon identifying the in-rush condition.

A method and system for controlling a three-phase drive connected to a three phase power source. The method includes connecting a converter to transfer power from the power source to a first direct current (DC) bus, where the converter and the first DC bus each have a neutral common point (NCP). Connecting a second DC bus to the first DC bus and configuring an inverter connected to the second DC bus to draw power from the second DC bus to provide a plurality of motor signals, the inverter having an inverter NCP. The method also includes connecting a neutral point selection device to the first DC bus NCP and selectively connecting to the converter NCP or the inverter NCP, the bus selection device configured to disconnect the converter NCP or the inverter NCP from the first DC bus NCP under selected conditions.