Operation coil drive device of electromagnetic contactor includes current detector and drive controller. The detector, when switching control is performed on operation coils of the contactor, detects coil current flowing through the coils. The controller controls an on/off time ratio of a semiconductor switching element wherein the on/off time ratio during close circuit control becomes larger than the on/off time ratio during holding control. Power supply voltage is switchingly applied to the coils at the on/off time ratio. The controller includes a determination locus setter and a close circuit state determiner. The setter sets a determination locus that continuously increases along a change locus of detected coil current during close circuit control. The determiner determines a contact point close circuit state by contact of a movable contact to a fixed contact based on deviation between the determination locus by the setter and the detected coil current detected.

There is provided an electromagnetic contactor which can easily and inexpensively change the DC operation type to the AC operation type. The electromagnetic contactor includes an electromagnet that opens and closes a contact by using DC excitation of a coil, a lower case that accommodates the electromagnet, external coil terminals that are disposed in the lower case beside the electromagnet, and a substrate that is accommodated in the lower case, and that has a rectifier circuit whose input side is connected to the external coil terminals and whose output side is connected to the coil so as to output a DC after converting an input AC to the DC. An inner surface of the lower case has a groove between the electromagnet and the external coil terminals. The substrate is held by being inserted into the groove.

Systems and methods are provided for controlling breaker operation of power systems during a close before excitation (CBE) operation. One method includes closing the breaker of a generator prior to alternator voltage excitation, using power sourced from a permanent magnetic generator (PMG) that is coupled to the alternator.

A step-by-step electric relay structure of a bistable type, comprising a mechanical part and an electric part, the mechanical part comprising push-button means to be operated by a user and the electric part comprising coil means, capacitor means, resistor means and diode means operatively interconnected to one another, the coil means comprising either two coils coupled in parallel to one another or a single coil polarized or biased with two polarities, thereby, as the push-button means are operated by the user to provide a switching or exchanging of at least a contact of the relay structure, either one of the two coils is shorted or the two polarities of the single coil are mutually reversed, thereby providing the electric relay structure with a logic SET function and a logic RESET function.

There is provided an electromagnetic contactor which can easily and inexpensively change the DC operation type to the AC operation type. The electromagnetic contactor includes an electromagnet that opens and closes a contact by using DC excitation of a coil, a lower case that accommodates the electromagnet, external coil terminals that are disposed in the lower case beside the electromagnet, and a substrate that is accommodated in the lower case, and that has a rectifier circuit whose input side is connected to the external coil terminals and whose output side is connected to the coil so as to output a DC after converting an input AC to the DC. An inner surface of the lower case has a groove between the electromagnet and the external coil terminals. The substrate is held by being inserted into the groove.

The present disclosure proposes a switching device which, when supplying and interrupting power by combining a mechanical relay with a solid-state relay, suppresses the effects of chattering from the mechanical relay, and thus makes it possible to stably supply and interrupt power. Provided is the switching device including: a semiconductor relay configured to switch between supplying and interrupting power from a power supply; a mechanical relay configured to be connected in parallel to the semiconductor relay and connected at one end to a control terminal of the semiconductor relay; and a switch configured to switch between supplying and interrupting current to the semiconductor relay. The semiconductor relay turns on by high voltage being applied to the control terminal after current flows through a coil of the mechanical relay and a contact is switched, and the semiconductor relay turns off by low voltage being applied to the control terminal after current stops flowing through the coil of the mechanical relay and the contact is switched.

An alternating current circuit breaker includes a first galvanic separation switch (SW2) and a bypass switch (SW1) in a live line, and a second galvanic separation switch (SW3) in a neutral line, and a semiconductor switch element connected parallel to the bypass switch (SW1). The semiconductor switch element includes a combination of a rectifier bridge (D1-D4) and an isolated gate bipolar transistor (IGBT). A processing unit is connected to a current measurement unit arranged in the live line, and is arranged to control the bypass switch (SW1), first and second galvanic separation switches (SW2, SW3) and the conducting state of the isolated gate bipolar transistor (IGBT) in case of detection of a short circuit condition.

A power cable assembly includes a power cable extending between a first end and a second end having a hot conductor and a neutral conductor. The power cable assembly includes a circuit protection device along the power cable between the first and second ends. The circuit protection device has a ground fault circuit interrupt (GFCI) device configured to sense a current difference on the hot and neutral conductors to initiate a triggering event. The circuit protection device has a high-power relay device connected to the GFCI device. The high-power relay device is connected to the hot conductor and is configured to open the hot line when the triggering event is initiated by the GFCI device.

A DC solenoid coil current controller includes a rectifier, pulse width modulator, and power driver. The rectifier inputs an alternating current signal and a direct current signal, and outputs a rectified signal using at least one of the alternating current signal and the direct current signal. The pulse width modulator outputs a pulse width modulated signal in response to the rectified signal. The power driver controls a DC solenoid coil using the pulse width modulated signal, thereby enabling a direct current DC solenoid coil to be controlled in response to the alternating current signal. A method of controlling current to a DC solenoid coil is also disclosed.

A switching apparatus is disclosed for switching a current, formed using a phase conductor and a switch arranged in the phase conductor, for the purpose of switching a transmission of current via the phase conductor. In addition, the switching apparatus includes a circuit for deriving a test current from the phase conductor via a ground conductor; a sensing apparatus for detecting the test current and an evaluation apparatus for evaluating the detected test current. A control apparatus is used to control closing of the switch arranged in the phase conductor. The evaluation apparatus is configured to detect a zero crossing for an alternating current and the control apparatus is set up to prompt closing of the switch arranged in the phase conductor in accordance with the time of the zero crossing. An embodiment reduces abrasion or wear on the switch as a result of short-circuit currents during switching-on.