The electromagnetic coupler uses a coil to induce voltage onto a transistor. By controlling the amount of current that flows through the coil, one is able to can control the strength of the magnetic field emitted by the inductor. And by the controlling the q-point of the transistor, the amount voltage and current induced onto the transistor it can then potentially be used as a switch or an amplifier without any electrical/electronic connection to the internal coil. The use of a transistor enables high speed switching and the potential amplification of communication signals.

The present invention relates to a filter circuit for eliminating capacitive inrush current occurring in electromagnetic coil control circuits controlling the actuator coil of electromagnetic contactors or relays. The filter circuit comprises input terminals to be connected with a direct current voltage, a first output terminal to be connected with a first terminal of the inductive load and a second output terminal to be connected to a second terminal of the inductive load, a first diode, wherein the cathode of the first diode is connected to said first output terminal and to said first input terminal, a second diode, wherein the anode of the second diode is connected to said second output terminal, and a filter capacitor which is connected between said second input terminal and to a node which interconnects the anode of said first diode and the cathode of said second diode.

The present invention relates to a filter circuit for eliminating capacitive inrush current occurring in electromagnetic coil control circuits controlling the actuator coil of electromagnetic contactors or relays. The filter circuit comprises input terminals to be connected with a direct current voltage, a first output terminal to be connected with a first terminal of the inductive load and a second output terminal to be connected to a second terminal of the inductive load, a first diode, wherein the cathode of the first diode is connected to said first output terminal and to said first input terminal, a second diode, wherein the anode of the second diode is connected to said second output terminal, and a filter capacitor which is connected between said second input terminal and to a node which interconnects the anode of said first diode and the cathode of said second diode.

A method for controlling an electromagnetic actuator including: applying a first control strategy in which first and third switches are kept in a closed state, whereas a second switch is switched between its open and closed states; detecting an occurrence of overconsumption of current in a coil of the actuator, by detecting that voltage measured on a control bus has exceeded a predefined voltage limit or by detecting that a duty cycle of the second switch has dropped below a threshold value; and in response, applying a second control strategy, instead of the first control strategy, in which the third switch is periodically opened in order to decrease the current supplied to the coil.

The present invention relates to a filter circuit for eliminating capacitive inrush current occurring in electromagnetic coil control circuits controlling the actuator coil of electromagnetic contactors or relays. The filter circuit comprises input terminals to be connected with a direct current voltage, a first output terminal to be connected with a first terminal of the inductive load and a second output terminal to be connected to a second terminal of the inductive load, a first diode, wherein the cathode of the first diode is connected to said first output terminal and to said first input terminal, a second diode, wherein the anode of the second diode is connected to said second output terminal, and a filter capacitor which is connected between said second input terminal and to a node which interconnects the anode of said first diode and the cathode of said second diode.

A relay device according to an embodiment of the present invention comprises: a relay unit in which a switch operates according to a voltage applied to a coil; a first control unit that controls a voltage applied to the coil by turning on and off a first switching element according to a first control signal; a first discharge unit and a second discharge unit that discharge a back electromotive force generated in the coil when the relay unit is turned off; and a second control unit including a second switching element, and controlling the back electromotive force to be discharged through the first discharge unit or the second discharge unit by turning on and off the switching element according to a second control signal.

Methods and apparatus for energizing and de-energizing a coil that controls a position of a contactor. In embodiments, a first switching device is coupled between the first end of a coil and a first potential node and a second switching device is coupled between the second end of the coil and a second potential node. A third switching device is coupled across a connection of the coil and the second switching device and a zener diode coupled across the second switching device. A contactor has a position determined by a current level through the coil.

Methods and apparatus for energizing and de-energizing a coil that controls a position of a contactor. In embodiments, a first switching device is coupled between the first end of a coil and a first potential node and a second switching device is coupled between the second end of the coil and a second potential node. A third switching device is coupled across a connection of the coil and the second switching device and a zener diode coupled across the second switching device. A contactor has a position determined by a current level through the coil.