Abstract: One embodiment describes a method that includes in a first switching operation of an electrical power switching system including three separately controllable single pole, single current-carrying path switching devices that provide three-phase power to a load, and control circuitry coupled to the switching devices to control closing and opening of the current-carrying paths, commanding at least one of the switching devices to open or close in advance of at least one other of the switching devices based upon a current zero-crossing or a predicted current zero-crossing of input three-phase power; and in subsequent switching operations alternating which of the three switching devices is closed or opened in advance of another of the switching devices.

Abstract: 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.

Abstract: 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.

Abstract: One embodiment describes a motor starter including a first single pole switching device that opens to disconnect power from a first winding of a motor; a second single pole switching device that closes after the first switching device opens to connect power to the first winding; a third single pole switching device that opens to disconnect power from a second winding of the motor; a fourth single pole switching device that closes after the third single pole switching device opens to connect power to the second winding; a fifth single pole switching device that opens to disconnect power form a third winding of the motor; and a sixth single pole switching device closes after the fifth single pole switching device opens to connect power to the third winding.

Abstract: 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.

Abstract: 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.

Abstract: The total current flow in a given electric circuit path is estimated by measuring the current in a second parallel current path and applying a ratio of the conductivity of the main and secondary path. Earth leakage current is measured by passing three wires through a toroid so as to detect differential current flow. Each wire is a conduction path wire parallel to each phase cable. The relative harmonic content between the fundamental and higher frequency components of a load current are calculated using a conduction path parallel to the main power cables.

Abstract: A testing assembly includes a power supply and at least one circuit phase corresponding to a circuit phase of a motor branch circuit assembly. The circuit phase includes a current detector, a transistor, and an isolating unit. The testing assembly also includes a switch selecting between a RUN mode and a TEST mode. The testing assembly is connected to the motor branch circuit assembly. Prior to placing the motor branch circuit assembly into operation, the testing assembly can provide low voltage testing on the circuit phases of the motor branch circuit assembly. The testing assembly can check for ground faults and line-to-line faults in the motor branch circuit assembly when placed into the Test mode. In this manner, faults destructive to the motor branch circuit assembly can be avoided and corrected.

Abstract: The total current flow in a given electric circuit path is estimated by measuring the current in a second parallel current path and applying a ratio of the conductivity of the main and secondary path. Earth leakage current is measured by passing three wires through a toroid so as to detect differential current flow. Each wire is a conduction path wire parallel to each phase cable. The relative harmonic content between the fundamental and higher frequency components of a load current are calculated using a conduction path parallel to the main power cables.

Abstract: 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.

Abstract: 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.

Abstract: Electrical operation of circuit breakers utilizing a straight pull dc magnet system with positive means of locking in OFF position is provided. The operating dynamics have advantages in fault coordination and discrimination for motor branch circuits. The construction offers physical and economic advantages in control solutions.

Abstract: Control of an induction motor is carried out to limit damaging arcing stress and mechanical stresses placed on the control contactor assembly and the induction motor resulting from the simultaneous or synchronous breaking and making of contactors employed to connect the windings of the motor to a power supply. Asynchronously connecting the windings to the power supply via the asynchronous or non-simultaneous closing of the contactors of a modular contactor assembly reduces the potentially damaging transient current, the associated torque oscillations, and mechanical stresses. The present invention is particularly applicable to delta motors that are started with its windings in a star or wye configuration followed by the reconnection of the windings in a delta configuration when the motor is at normal running speed.

Abstract: A self-powered wireless transducer is disclosed for monitoring external physical conditions, such as excessive vibrations in a bearing. The transducer includes an energy conversion source, such as a piezoelectric sensor to sense the external physical condition and create a power and characteristic signal that is used to power an RF transmitting circuit. A transmitter is provided to transmit signals indicative of the external physical condition, or changes in that physical condition, such as increased vibrations in a bearing to detect bearing faults before a breakdown. In this manner, the monitored machinery can be shutdown in an orderly manner and preventative maintenance can be completed. The self-powered wireless transducer includes an voltage storage device to receive electrical voltage from the piezoelectric sensor and a voltage detector to detect the level of voltage on the voltage storage device.