The present invention provides a method of determining an electrical operating time of a circuit breaker (140) in a multiphase electrical system having a subsystem (160) at an electric potential resulting from electrical characteristics of electrical components within the subsystem. The method comprises monitoring (145) the voltage of the subsystem in the first phase, determining a first rate of change from the monitored voltage in the first phase, detecting at least one instance of switching based on the first rate of change, determining an electrical operating time of the circuit breaker based on the detected at least one instance of switching and an instance at which a command for switching was provided to the circuit breaker.

An intelligent electronic device (IED) may provide point on wave switching. The IED may receive a control operation request, and determine when to issue a control command to cause a switch to change positions. The actuation of the switch may occur at a target point on an alternating current. An IED may have a processor that is too slow to implement a switch when a desired point on an alternating current first occurs. Accordingly, some embodiments may compensate for the processing speed of an IED by determining a number of processor cycles needed (in advance) to issue a control command so that the resulting action results in the desired point on wave open or close.

A PCB motor controller comprises relays mounted on a PCB and interconnected to power traces in or on the PCB to receive incoming three-phase power and to output three-phase power to a motor. Control power traces in or on the PCB connect the relays to control circuitry, also mounted on the PCB. A power supply is mounted on the PCB and connected to the control circuitry to provide power for its operation and for switching of the relays. The relays are switched in accordance with a point-on-wave (POW) switching scheme, allowing for the use or relays and the PCB, which may not otherwise be suitable for motor control applications.

A PCB motor controller comprises relays mounted on a PCB and interconnected to power traces in or on the PCB to receive incoming three-phase power and to output three-phase power to a motor. Control power traces in or on the PCB connect the relays to control circuitry, also mounted on the PCB. A power supply is mounted on the PCB and connected to the control circuitry to provide power for its operation and for switching of the relays. The relays are switched in accordance with a point-on-wave (POW) switching scheme, allowing for the use or relays and the PCB, which may not otherwise be suitable for motor control applications.

A PCB motor controller comprises relays mounted on a PCB and interconnected to power traces in or on the PCB to receive incoming three-phase power and to output three-phase power to a motor. Control power traces in or on the PCB connect the relays to control circuitry, also mounted on the PCB. A power supply is mounted on the PCB and connected to the control circuitry to provide power for its operation and for switching of the relays. The relays are switched in accordance with a point-on-wave (POW) switching scheme, allowing for the use or relays and the PCB, which may not otherwise be suitable for motor control applications.

An intelligent electronic device (IED) may provide point on wave switching. The IED may receive a control operation request, and determine when to issue a control command to cause a switch to change positions. The actuation of the switch may occur at a target point on an alternating current. An IED may have a processor that is too slow to implement a switch when a desired point on an alternating current first occurs. Accordingly, some embodiments may compensate for the processing speed of an IED by determining a number of processor cycles needed (in advance) to issue a control command so that the resulting action results in the desired point on wave open or close.

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 of the single-phase switching devices includes a direct current electromagnetic operator that receives a direct current control signal from control circuitry, in which the direct current control signal instructs the single phase switching device to open or close a single current carrying path in the single phase switching device at a desired time; stationary contacts disposed in a device housing; and a movable assembly that is displaced by energizing or de-energizing the electromagnetic operator, in which the movable assembly includes movable contacts that, with the stationary contacts, open and close the single current carrying path.

A method and apparatus using electromagnetic switching in a two-step connection process is provided to minimize surge currents and torque oscillations in three-phase motors during starts.

A circuit breaker includes: at least one external conductor section from an external conductor supply terminal of the circuit breaker to an external conductor load terminal of the circuit breaker; and one neutral conductor section from a neutral conductor terminal of the circuit breaker to a neutral conductor load terminal of the circuit breaker. A mechanical bypass switch is arranged in the at least one external conductor section. A semiconductor circuit arrangement of the circuit breaker, which semiconductor circuit arrangement comprises a four-quadrant switch, is connected in parallel with the bypass switch. A current measuring arrangement is arranged in the at least one external conductor section and is connected to an electronic control unit of the circuit breaker. The electronic control unit is configured to operate the bypass switch and the semiconductor circuit arrangement in a prespecifiable manner. A voltage-dependent resistor is arranged in parallel with the bypass switch.

A circuit breaker includes: at least one external conductor section from an external conductor supply connection in the circuit breaker to an external conductor load connection in the circuit breaker; and a neutral conductor section from a neutral conductor connection in the circuit breaker to a neutral conductor connection in the circuit breaker. The at least one external conductor section includes a mechanical bypass switch and a first mechanical isolating switch which are serially arranged. A second mechanical isolating switch is arranged in the neutral conductor section. A semiconductor circuit arrangement in the circuit breaker is connected in parallel to the bypass switch. A current measuring device is arranged in the at least one external conductor section that is linked to an electronic control unit in the circuit breaker. The electronic control unit operates the bypass switch, the first and second mechanical isolating switches, and the semiconductor circuit arrangement.