A method for mounting an interlock module between two contactors, including: providing a first contactor having a first mounting surface and a first movable iron core assembly and a second contactor having a second mounting surface and a second movable iron core assembly, and placing the first mounting surface and the second mounting surface face to face; providing the interlock module comprising a first slider, a second slider and a housing formed separately from the first slider and the housing, an interlocking portion being mounted in the housing for interacting with the first slider and the second slider; connecting the first slider to the first movable iron core assembly of the first contactor; connecting the second slider to the second movable iron core assembly of the second contactor; assembling the housing to the first slider and the second slider; and fixing the housing.

One embodiment describes a wye-delta starter, which includes a first single pole, single current carrying path switching device that selectively connects and disconnects a first winding of a motor in a wye configuration; a second single pole, single current carrying path switching device that selectively connects and disconnects the first winding in a delta configuration, in which the first switching device and the second switching device are coupled via a first interlock; a third single pole, single current carrying path switching device that selectively connects and disconnects a second winding and a third winding of the motor in the wye configuration; a fourth single pole, single current carrying path switching device that selectively connects and disconnects the second winding in the delta configuration, in which the third switching device and the fourth switching device are coupled via a second interlock; and a fifth single pole, single current carrying path switching device that selectively connects and disconnects the third winding in the delta configuration.

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 system may include a relay device that includes armatures associated with phases of voltage signals. The system may also include relay coils, such that each relay coil may receive a respective voltage that magnetizes a respective relay coil, thereby causing the respective armature to move from a respective first position to a respective second position. The system may also include a control system that receive an indication that a fault condition is present, identify a first phase of the phases of voltage signals that is expected to be the next phase of the phases to cross zero, and send a signal to the relay device in response to identifying the first phase. The signal is configured to cause a first relay coil of the relay coils to energize or deenergize.

An electromechanical relay may comprise a housing and one or more terminal pairs. Each terminal pair may comprise a first terminal connected to a first contact, a second terminal connected to a second contact, a first armature connected to a first coil and coupled to the first contact, and/or a second armature connected to a second coil and coupled to the second contact. Supplying power to the first and the second coils may enable movements of the first and the second contacts by moving the first and the second armatures, thereby resulting in an electrical connection between the first and the second contacts. Removing the power may comprise the first contact to be isolated from the second contact. A central armature lock may be inserted through the housing and into the recesses of each of the first and second armatures, which may reduce movement of the armatures.

A system may include a relay device that includes armatures associated with phases of voltage signals. The system may also include relay coils, such that each relay coil may receive a respective voltage that magnetizes a respective relay coil, thereby causing the respective armature to move from a respective first position to a respective second position. The system may also include a control system that receive an indication that a fault condition is present, identify a first phase of the phases of voltage signals that is expected to be the next phase of the phases to cross zero, and send a signal to the relay device in response to identifying the first phase. The signal is configured to cause a first relay coil of the relay coils to energize or deenergize.

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 method for mounting an interlock module between two contactors, including: providing a first contactor having a first mounting surface and a first movable iron core assembly and a second contactor having a second mounting surface and a second movable iron core assembly, and placing the first mounting surface and the second mounting surface face to face; providing the interlock module comprising a first slider, a second slider and a housing formed separately from the first slider and the housing, an interlocking portion being mounted in the housing for interacting with the first slider and the second slider; connecting the first slider to the first movable iron core assembly of the first contactor; connecting the second slider to the second movable iron core assembly of the second contactor; assembling the housing to the first slider and the second slider; and fixing the housing.

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.