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 single-phase switching device including a direct current electromagnetic operator that in operation receives a direct current control signal for switching of the device, stationary contacts disposed in a respective device housing, and a movable assembly that in operation is displaced by energizing the operator and that include movable contacts that open and close, with the stationary contacts, a single current carrying path through the respective single-phase switching device; in which each of the single-phase switching devices receives control signals from control circuitry coupled to the operators of the respective single-phase switching devices to cause at least one of the single-phase switching devices to open or close the single current carrying path at a desired time coordinated with a current zero-crossing or a predicted current zero-crossing of a phase of three-phase power.

A switching system for an electricity meter, an electricity meter with a switch system and a method of switching switch are provided. In order to improve lifetime of the switch the timing of outputting a switching signal is adjusted based on a time difference between previously outputting the switching signal and achieving a predefined switching state.

A method for operating a drive of a vacuum interrupter in opening mode includes: dividing an opening movement of at least one movable contact into serial phases, an opening phase, and an isolating phase, driven in at least two different velocities. In the opening phase a velocity of the opening movement is lower than in the isolating phase.

One embodiment describes a method that includes determining, using a control circuitry, temperature of a switching device before a make operation by applying a measurement current to an operating coil of the switching device, wherein the measurement current is insufficient to make the switching device; and determining voltage at the operating coil when the measurement current is applied, in which the voltage at the operating coil is directly related to the temperature. The method further includes determining, using the control circuitry, when to apply a pull-in current to the operating coil to close the switching device based at least in part on the voltage at the operating coil, such that the switching device makes at a desired time.

A switching system for an electricity meter, an electricity meter with a switch system and a method of switching switch are provided. In order to improve lifetime of the switch the timing of outputting a switching signal is adjusted based on a time difference between previously outputting the switching signal and achieving a predefined switching state.

A method for operating a drive of a vacuum interrupter in opening modus includes: dividing an opening movement of at least one movable contact into serial phases, an opening phase, and an isolating phase, driven in at least two different velocities. In the opening phase a velocity of the opening movement is lower than in the isolating phase.

An electrical utility meter includes metering circuitry configured for connection to at least one utility power line and a service disconnect member. The metering circuitry is configured to receive an electrical signal corresponding to a line voltage on the at least one utility power line. The service disconnect member is configured for connection to the at least one utility power line. A control circuit is configured to deliver a control signal to the service disconnect member synchronously with a zero crossing of the electrical signal corresponding to the line voltage on the at least one utility power line.

One embodiment describes a tangible, non-transitory, computer-readable medium storing instructions executable by a processor in a control circuitry. The instructions include instructions to receive an instruction to make a switching device; determine, using the control circuitry, a voltage waveform of a power source; determine, using the control circuitry, a desired time to make the switching device based at least in part on the source voltage waveform; determine, using the control circuitry, an expected make time of the switching device; and determine, using the control circuitry, when to apply a pull-in current to make the switching device at the desired time based at least in part on the expected make time and the desired time to make.

One embodiment describes a switching device system, which includes a first single pole switching device that selectively connects and disconnects a first phase of electric power to a first winding of a three phase motor; a second single switching device that selectively connects and disconnects a second phase of electric power to a second winding of the three phase motor; in which the first and second single pole switching devices control temperature of the motor by, at a first time, connecting the first phase and the second phase electric power to the motor.

A simple, economically efficient, synchronized switching system for control of a three phase motor contactor utilizes only Voltage monitoring to determine zero crossings and knowledge of the sinusoidal power waveforms and operational delay period of the contactor, to synchronize operation of the contacts at low power. The phases can be serially utilized for zero crossing detection upon Close or Open commands, so as to spread the wear over each set of contacts. Expensive metal at the contact surfaces can therefore be used more efficiently. For arc energy reduction upon contact opening, knowledge of Line-Load Voltage on at least one phase can be used to derive an empirical determination of the voltage angle at opening which yields the lowest arc energy.