A system includes a dry contact with a first pair of switchable electrodes, a wet contact with a second pair of switchable electrodes, an arc suppressor, and a controller circuit operatively coupled to the arc suppressor and the first and second pairs of switchable electrodes. The controller circuit is configured to detect a failure of the wet contact and determine a stick duration associated with the first pair of switchable electrodes. The stick duration is based on a duration between an instance when a coil of the dry contact is deactivated and an instance of separation of the first pair of switchable electrodes during deactivation of the coil. The controller circuit generates, in-situ and in real-time, health assessment for the first pair of switchable electrodes based on a comparison of the determined stick duration with an average stick duration associated with a window of observation.

A power contact electrode plasma therapy circuit includes a pair of terminals adapted to be connected to a set of switchable contact electrodes of a power contact. A plasma ignition detector is configured to detect an electrical parameter over the switchable contact electrodes indicative of the formation of plasma between the switchable contact electrodes and output a plasma ignition signal based on the electrical parameter as detected. A plasma burn memory is configured to receive and store the plasma ignition signal. A controller circuit is configured to receive from the plasma burn memory the plasma ignition signal, start a time based on receipt of the plasma ignition signal, and upon the timer meeting a time requirement, output a plasma extinguish command. A plasma extinguishing circuit, configured to bypass the pair of terminals upon receiving the trigger signal to extinguish the plasma between the switchable contact electrodes.

An electronic control device includes an input terminal connected to a second terminal of a switch via an electrically conductive lead, an input circuit connected to the input terminal via a signal line, and a microcontroller to detect whether the switch is in an electrically conducting state or an electrically non-conducting state based on an output signal from the input circuit, and to perform at least one process in accordance with a detected result. The input circuit includes a first resistor connected to a supply voltage or ground and to the signal line, and a transient current circuit connected to the supply voltage or ground and to the signal line, the transient current circuit including a second resistor that allows a transient current to flow through the switch when the switch transitions from the electrically non-conducting state to the electrically conducting state.

A circuit for controlling an input current, the circuit includes a first input port configured to receive the input current. A current detector detects an input current value of the input current and generates a control signal indicative of the input current value. A first output port outputs an output current to a load. A second output port receives the output current from the load. A control circuit provides a low-impedance path in parallel with the load in response to the control signal indicating the input current value is below a threshold value.

A power supply system includes a power source, a relay, a switch, and a controller. The relay is interposed between the power source and a load. The switch is configured to be coupled to the load in a state where the switch allows or disallows for power supply from the power source to the load when the relay is in a closed state. The controller is configured to control an operation of the switch. The controller is configured to execute forced driving control at a time of a closing operation of the relay. The forced driving control causes the switch to operate independently of a request for driving the load and thereby causes power to be supplied from the power source to the load.

A contact wetting circuit 100 is disclosed for supplying wetting current to sense the state of dry contacts of a switch SW1 setting for an electronic device 10. The contact wetting circuit includes an RC circuit 110 having a resistor R1 and a capacitor C1, and a controller 120 connected to a power supply 130 of the device. The controller supplies a first voltage to the RC circuit to produce a charging current having an average current and/or a peak current below the wetting current parameter of the dry contacts. The charging current is used to charge the capacitor C1 during the first time period. The controller stops the supply of the first voltage to the RC circuit after sufficient charging to allow the charged capacitor C1 to supply a second voltage, across the switch SW1, to produce a wetting current. Thereafter, the controller polls and senses the state of the switch SW1, and performs certain operations accordingly.

A circuit includes an evaluation node through which current flows from a voltage source node to a sensed switch when the sensed switch is closed. First and second control switches are disposed between the voltage source node and the evaluation node to switch between first and second current paths for the current. The current passes through the first control switch when flowing along the first current path. The second control switch is coupled to a control terminal of the first control switch to deactivate the first control switch and allow the current to flow through the second current path. Multiple passive circuit elements are configured to establish first and second current levels for the current. The passive circuit elements are disposed between the voltage source node and the evaluation node in a circuit arrangement in which no current path to ground is present when the sensed switch is open.

There is a need to monitor and control the state of relays and circuit breakers within power distribution systems. The monitoring of a relay state, i.e. open or closed, is often performed by applying a monitoring signal to sensing contacts added to the relay. Manufactures of such systems have chosen many different voltages for their own. monitoring systems making it difficult to interconnect dissimilar monitoring systems. A signal conditioning circuit is provided that can cope with a large input voltage range and can be configured to allow may items of equipment(which may be new item or legacy items) to be connected to a controller.

A process for automated contact wetting in a sensor circuit includes generating a first current through a contact by sequencing a first circuit on, the first current exceeding a wetting threshold of the contact, and reducing current through the contact to a second current by sequencing a second circuit on, the second current being below the wetting threshold.

An electrical circuit includes a contact with a pair of switchable electrodes, the contact configured to cycle through make and break transitions while conducting current. The electrical circuit further includes an arc suppressor, at least one sensor, and a controller circuit. The arc suppressor is coupled across the pair of switchable electrodes and is to extinguish an arc formed across the pair of switchable electrodes during the make and break transitions of the contact. The at least one sensor is coupled to the pair of switchable electrodes and is configured to generate sensor data. The controller circuit includes a plurality of registers and is configured to detect a fault condition associated with the contact based on the sensor data. The controller circuit further sequences contact opening of the contact based on the detected fault condition and a timing value stored in at least one register of the plurality of registers.