An integrated circuit for demagnetizing an inductive load includes a first switch to control current supplied by a voltage supply to the inductive load. A Zener diode includes an anode connected to a control terminal of the first switch and a cathode connected to the voltage supply. A second switch includes a control terminal and first and second terminals. A temperature sensing circuit is configured to sense a temperature of the first switch and to generate a sensed temperature. A comparing circuit includes inputs that receive a reference temperature and the sensed temperature and an output connected to the control terminal of the second switch.

A driving circuit includes a relay driver for selectively connecting a relay coil with (a) a first current path between the relay driver and a relay voltage input or (b) a second current path between the relay driver and a ground connection. Another relay driver selectively connects the coil with (a) a third current path between the other relay driver and the relay voltage input or (b) a fourth current path between the other relay driver and the ground connection. The relay drivers may connect the coil between the second and third current paths for latching the relay, and between the first and fourth current paths for unlatching the relay. The driving circuit applies signals of opposite polarity and different magnitudes through the coil to latch and unlatch the relay. The signal for unlatching can be of lower voltage than the signal for latching the relay.

An apparatus for controlling the electrical connection of an electrical load (2), which is arranged at a distance from the apparatus, to a control voltage source (4) which is associated with said electrical load, wherein control is performed by means of two control lines (6, 8) which bridge the physical distance between the apparatus and the load plus the control voltage source and which are connected to a control output (10, 12) of the apparatus, wherein the apparatus has a transducer (14) which detects the value of a state variable (16) of a fluid, and wherein control of the connection is performed depending on the respectively detected value of the state variable (16) exceeding and/or falling below a selectable threshold value, is characterized in that the transducer is formed by a measurement transducer (14) which converts the value of the respectively detected state variable (16) into an electrical signal (18), in that the apparatus has an electronics device (20) for evaluating said electrical signal (18) and for controlling the connection depending on the evaluation, in that the connection is made by means of a controllable electronic switching device (26), which is connected to the control output (10, 12), of the apparatus at least over a first predefinable time period, and in that the power supply device of the apparatus is fed from the voltage of the control voltage source (4) which is applied to the control output (10, 12) of the apparatus via the control lines (6, 8), depending on the switching state of the electronic switching device (26), at least over a further second time period which lies outside the first time period.

The invention provides a control circuit of a switch device. A single output pin of the control unit outputs an enable signal to control terminals of two switch units to control an on-state of the two switch units, and adjust a current size of a control current of the on-state of the switch device. One of the switch units after receiving the enable signal for a predetermined time is switched to an off-state, so as to reduce power consumption of the switch device.

A switching system for switching an electrical device, comprising: a vacuum interrupter including a fixed electrode, and a mobile electrode, the mobile electrode configured to move between a closed position and an open position. The switching system further comprising an elastic return means configured to apply a driving force to the mobile electrode, and a retaining member for retaining the elastic return means, the retaining member configured to moves from a retention configuration, in which the elastic return means is immobilized, into a movement configuration, in which the elastic return means is released. The switching system is configured so that the mobile electrode moves from the closed position to the open position under the action of the elastic return means when the retaining member leaves its retention configuration.

A switching system for switching an electrical device, comprising: a vacuum interrupter including a fixed electrode, and a mobile electrode, the mobile electrode configured to move between a closed position and an open position. The switching system further comprising an elastic return means configured to apply a driving force to the mobile electrode, and a retaining member for retaining the elastic return means, the retaining member configured to moves from a retention configuration, in which the elastic return means is immobilized, into a movement configuration, in which the elastic return means is released. The switching system is configured so that the mobile electrode moves from the closed position to the open position under the action of the elastic return means when the retaining member leaves its retention configuration.

In a circuit breaker arrangement, this disclosure describes a method and circuit design enables a current transformer to be used to detect ground faults in circuit breakers (such as a main-tie-main circuit breakers) that have been designed to receive signals from Rogowski coils.

The present invention is directed to an electrical wiring device that includes an automatic test circuit configured to commence an automatic test at a predetermined time such that a test current propagates on a test conductor. The sensor assembly provides a sensor test output responsive to the test current only if both the differential transformer and the grounded neutral transformer are operative. A fault detector circuit is configured to generate a test detection signal in response to the sensor test output only if the fault detector circuit is operable and the at least one power supply is substantially charged. A device integrity evaluation circuit includes a timer that effects a tripped state when a time measurement exceeds a threshold, the test detection signal resetting the time measurement when properly wired before the time measurement exceeds the predetermined threshold but does not reset the time measurement when miswired.

The present invention is directed to an electrical wiring device that includes an automatic test circuit configured to commence an automatic test at a predetermined time such that a test current propagates on a test conductor. The sensor assembly provides a sensor test output responsive to the test current only if both the differential transformer and the grounded neutral transformer are operative. A fault detector circuit is configured to generate a test detection signal in response to the sensor test output only if the fault detector circuit is operable and the at least one power supply is substantially charged. A device integrity evaluation circuit includes a timer that effects a tripped state when a time measurement exceeds a threshold, the test detection signal resetting the time measurement when properly wired before the time measurement exceeds the predetermined threshold but does not reset the time measurement when miswired.

One embodiment describes a three-phase electromechanical switching device, which includes three single-phase switching devices mechanically and electrically coupled in parallel with one another, each single-phase switching device including a direct current electromagnetic operator that in operation receives a direct current control signal for switching of the device, stationary contacts disposed in a respective device housing, and a movable assembly that in operation is displaced by energizing the operator and that include movable contacts that open and close, with the stationary contacts, a single current carrying path through the respective single-phase switching device; in which each of the single-phase switching devices receives control signals from control circuitry coupled to the operators of the respective single-phase switching devices to cause at least one of the single-phase switching devices to open or close the single current carrying path at a desired time coordinated with a current zero-crossing or a predicted current zero-crossing of a phase of three-phase power.