A short detection circuit includes a reference voltage generator that generates a reference voltage based on a power voltage, a comparison voltage generator that generates a comparison voltage that is higher or lower than a normal state voltage of a short detection target voltage by a predetermined adjustment voltage based on the reference voltage, a voltage comparator that generates a comparison result voltage by comparing the short detection target voltage with the comparison voltage, and a short detector that determines whether a target line transferring the short detection target voltage is electrically shorted based on the comparison result voltage. Thus, the short detection circuit can accurately detect an electrical short due to particles that exist in a display device.

A short detection circuit includes a reference voltage generator that generates a reference voltage based on a power voltage, a comparison voltage generator that generates a comparison voltage that is higher or lower than a normal state voltage of a short detection target voltage by a predetermined adjustment voltage based on the reference voltage, a voltage comparator that generates a comparison result voltage by comparing the short detection target voltage with the comparison voltage, and a short detector that determines whether a target line transferring the short detection target voltage is electrically shorted based on the comparison result voltage. Thus, the short detection circuit can accurately detect an electrical short due to particles that exist in a display device.

An intelligent leakage current detection and interruption device for a power cord, including a switch module configured to control electrical connection of first and second power lines between input and output ends; a leakage current detection module, including first and second leakage current detection lines coupled in series, configured to detect a leakage current on the first and second power lines, respectively; a detection monitoring module, coupled in series to the first and second leakage current detection lines and to the first and second power lines, configured to detect an open circuit condition in the first or second leakage current detection line; and a drive module, coupled to the switch module, the leakage current detection module and the detection monitoring module, configured to drive the switch module to cut off power to the output end in response to any detected leakage current or open circuit condition.

Appliances that include a ground fault door latch trip circuit that leverages a door latch circuit of the appliance to open one or more component relays upon detection of a current leakage event are provided. In particular, the ground fault door latch trip circuit can provide one or more shunt paths when a ground fault event is detected. The shunt paths can shunt current from a door latch to ground, such that the door latch circuit operates as if the door of the appliance has been opened.

A power conversion device may include a first inverter to which one end of each phase winding of a motor is coupled, a second inverter to which the other end of each phase winding is coupled, and a switch circuit having at least one of a first switch element that switches between connection and disconnection of the first inverter to and from a ground, a first protection circuit being coupled in parallel to the first switch element, and a second switch element that switches between connection and disconnection of the second inverter to and from the ground, a second protection circuit being coupled in parallel to the second switch element.

A power pedestal including a receptacle, a circuit breaker electrically connected between a power source and the receptacle and including separable contacts structured to trip open and electrically disconnect the receptacle from the power source, a current sensor structured to detect current flowing to the receptacle, and a ground fault detection device structured to sense a ground fault based on an output of the current sensor and to control the circuit breaker to trip open the separable contacts in response to detecting the ground fault. The ground fault detection device has an adjustable range of ground fault protection.

A power pedestal including a receptacle, a circuit breaker electrically connected between a power source and the receptacle and including separable contacts structured to trip open and electrically disconnect the receptacle from the power source, a current sensor structured to detect current flowing to the receptacle, and a ground fault detection device structured to sense a ground fault based on an output of the current sensor and to control the circuit breaker to trip open the separable contacts in response to detecting the ground fault. The ground fault detection device has an adjustable range of ground fault protection.

The invention relates to a device for detecting a leakage current, comprising means (124) for measuring a current from an electrical circuit of a vehicle, in particular a motor vehicle, said detection device being configured to be placed on board said vehicle and being such that the measuring means (124) comprise: a magnetic core (128) configured to be passed through by one or a plurality of conductive elements (127) traversed by the current from the electrical circuit, said conductive element(s) (127) forming a primary winding; a secondary winding (130), wound around the core (128), to generate a magnetic flux from a reference current; and an oscillator (132) for generating the reference current though the secondary winding (130), the reference current being configured to saturate said core (128). According to the invention, the value of the current of the primary winding (127) is obtained from the average value of the current at the secondary winding (130) over a period of oscillation covering a complete core (128) magnetization and demagnetization cycle. The invention also relates to various on-board systems using said device.

Overcurrent protection of an electrically powered, motorized device, such as a power tool, wherein the tool includes a tool housing, an output assembly, a trigger, an electrical safety device, a motor, an indicator, a controller, and a power source. The electrical safety device, for example a fuse, is disposed in series with a power connection from the power source to the controller. The controller measures current passing through the electrical safety device in time intervals when the trigger is actuated. The controller determines accumulated thermal energy passing through the electrical safety device, and compares the accumulated thermal energy to a threshold. If the accumulated thermal energy exceeds the threshold, the controller ceases or discontinues to allow power to be provided to the motor from the power source, thereby shutting off the motor. The controller may also activate the indicator to indicate a fault to the user.

The invention relates to a method and to an electrical protection device for detecting a disconnection of a protective conductor connection with a subsystem in ungrounded and grounded power supply systems and in a grounded power supply system comprising a converter system.

The invention is based on the idea that the disconnection of the protective conductor connection with a subsystem will reduce the sum of the network leakage capacitances of the power supply system by the value of the network leakage capacitance of the subsystem. The necessary distinction between a subsystem in operation having a disconnected protective conductor connection and a shut-off subsystem is made by evaluating the current total power consumed via the power supply system. In the case of a converter system connected to the subsystem, the protective conductor disconnection is detected by examining the leakage current spectra that are characteristic of the converter system.