A circuit breaker comprises a solid-state switch, an air-gap electromagnetic switch, switch control circuitry, a zero-crossing detection circuit, and a current sensor. The solid-state and air-gap switches are connected in series in an electrical path between line input and load output terminals of the circuit breaker. The switch control circuitry controls the solid-state and air-gap switches. The zero-crossing detection circuit detects zero crossings of an AC power waveform on the electrical path. The current sensor senses current flow in the electrical path to detect a fault condition based on the sensed current flow. In response to a detected fault condition, the switch control circuitry generates control signals to place the solid-state switch into a switched-off state and place the air-gap switch into a switched-open state after the solid-state switch is placed into the switched-off state. The switch control circuitry utilizes zero-crossing detection signals output from the zero-crossing detection circuit to determine when to place the air-gap switch into the switched-open state.

A circuit breaker comprises a solid-state bidirectional switch, a switch control circuit, current and voltage sensors, and a processor. The solid-state bidirectional switch is connected between a line input terminal and a load output terminal of the circuit breaker, and configured to be placed in a switched-on state and a switched-off state. The switch control circuit control operation of the bidirectional switch. The current sensor is configured to sense a magnitude of current flowing in an electrical path between the line input and load output terminals and generate a current sense signal. The voltage sensor is configured to sense a magnitude of voltage on the electrical path and generate a voltage sense signal. The processor is configured to process the current and voltage sense signals to determine operational status information of the circuit breaker, a fault event, and power usage information of a load connected to the load output terminal.

A circuit breaker includes a circuit breaker housing, an air-gap switch disposed within the housing, and a first visual indicator configured to provide an indication of an open state and a closed state of the air-gap switch. The first visual indicator includes a first window that is formed as part of the circuit breaker housing, and first and second indicator elements disposed within the circuit breaker housing. The first indicator element is configured to move into position behind the first window as the air-gap switch is placed into the open state and thereby provide a visual indication of the open state of the air-gap switch. The second indicator element is configured to move into position behind the first window as the air-gap switch is placed into the closed state and thereby provide a visual indication of the closed state of the air-gap switch.

A circuit breaker includes an electromechanical switch, a current sensor, a voltage sensor, and a processor. The electromechanical switch is serially connected between a line input terminal and a load output terminal of the circuit breaker, and configured to be placed in a switched-closed state or a switched-open state. The current sensor is configured to sense a magnitude of current flowing in a path between the line input and load output terminals and generate a current sense signal. The voltage sensor is configured to sense a magnitude of voltage at a point on the path between the line input and load output terminals and generate a voltage sense signal. The processor is configured to receive and process the current sense signal and the voltage sense signal to determine operational status information of the circuit breaker and determine power usage information of a load connected to the load output terminal.

A circuit breaker includes a solid-state switch, a sense resistor, a current detection circuit, and a switch control circuit. The solid-state switch and sense resistor are connected in series in an electrical path between a line input terminal and a load output terminal of the circuit breaker. The current detection circuit is configured to (i) sample a sense voltage that is generated across the sense resistor in response to load current flowing through the sense resistor, (ii) detect an over-current fault condition based on the sampled sense voltage, and (iii) output a fault detection signal in response to detecting the over-current fault condition. The switch control circuit is configured to control the solid-state switch, wherein the switch control circuit is configured to switch-off the solid-state switch in response to the fault detection signal output from the current detection circuit.

A method of performing a circuit-breaking and closing operation in a three-phase system having a first phase, a second phase lagging the first phase by 120, and a third phase lagging the first phase by 240, includes: a) opening only one of the first phase, the second phase and the third phase before a zero crossing of a current of the corresponding phase, b) opening the remaining phases of the first phase, the second phase and the third phase after step a), and c) closing the first phase, the second phase and the third phase simultaneously or essentially simultaneously at a phase to ground voltage of the phase of the first phase, the second phase and the third phase which lagging the phase that was opened in step a) by 120 in a time range from 60 before a peak of the phase to 90 after the peak.

A sliding power contact and method includes a mobile load device connector and a socket. The mobile load device connector includes a non-current power pin having a first length, a current power pin having a second length less than the first length, a neutral pin, and a ground pin. The socket includes a non-current power contact configured to electrically couple with the non-current power pin, a current power contact configured to electrically couple with the current power pin, a neutral contact configured to electrically couple with the neutral pin, and a ground pin configured to electrically couple with the ground pin. An arc suppressor is directly coupled to at least one of the non-current power pin and the non-current power contact, wherein the arc suppressor, the non-current power pin and the non-current power contact form a current path between the current power pin and the current power contact.

An arc suppressing circuit configured to suppress arcing across a power contactor coupled to an alternating current (AC) power source having a predetermined number of phases, each contact of the power contactor corresponding to one of the predetermined number of phases includes a number of dual unidirectional arc suppressors equal to the predetermined number of phases of the AC power source. Each dual unidirectional arc suppressor includes a first phase-specific arc suppressor configured to suppress arcing across the associated contacts in a positive domain, a a second phase-specific arc suppressor configured to suppress arcing across the associated contacts in a negative domain, and a coil lock controller, configured to be coupled between a contact coil driver of the power contactor, configured to detect an output condition from the contact coil driver and inhibit operation of the first and second phase-specific arc suppressors over a predetermined time.

A method for synchronizing opening of a circuit breaker is presented. The circuit breaker is arranged to interrupt a current to an inductive load. The method is performed in a control device (2) and comprises measuring (S100) a reference signal as a function of time for a circuit breaker (1) connected to an inductive load (5), obtaining (S110) an indication of a power factor of the inductive load through the circuit breaker, determining (S120) an arcing time for opening of the circuit breaker, the arcing time being dependent on the obtained indication of a power factor, predicting (S130) a zero crossing of a current through the circuit breaker based on the measured reference signal, and providing (S140) contact separation of a contact pair of the circuit breaker at a point of time before the predicted zero crossing, the point of time being determined by the determined arcing time and the predicted zero crossing. A control device, a circuit breaker arrangement, and a computer program for synchronizing opening of a circuit breaker are also presented.

A method of performing a circuit-breaking and closing operation in a three-phase system having a first phase, a second phase lagging the first phase by 120, and a third phase lagging the first phase by 240, includes: a) opening only one of the first phase, the second phase and the third phase before a zero crossing of a current of the corresponding phase, b) opening the remaining phases of the first phase, the second phase and the third phase after step a), and c) closing the first phase, the second phase and the third phase simultaneously or essentially simultaneously at a phase to ground voltage of the phase of the first phase, the second phase and the third phase which lagging the phase that was opened in step a) by 120 in a time range from 60 before a peak of the phase to 90 after the peak.