Abstract: An apparatus includes a plurality of DC buses and a plurality of inverter circuits, respective ones of which are coupled to respective ones of the plurality of DC buses. The apparatus further includes a control circuit configured to generate a representative DC voltage signal based on DC voltage signals for respective ones of the DC buses, to generate a first modulation control signal from the representative DC voltage signal, to generate second modulation control signals for the respective inverter circuits from the representative DC voltage signal and the first modulation control signal that are normalized based on the DC voltage signals for the buses and the representative DC voltage signal, and to modulate the inverter circuits responsive to respective ones of the second modulation control signals. The representative DC voltage signal may represent a maximum of the DC voltages for the respective DC buses.

Abstract: An apparatus includes a plurality of DC buses and a plurality of inverter circuits, respective ones of which are coupled to respective ones of the plurality of DC buses. The apparatus further includes a control circuit configured to generate a representative DC voltage signal based on DC voltage signals for respective ones of the DC buses, to generate a first modulation control signal from the representative DC voltage signal, to generate second modulation control signals for the respective inverter circuits from the representative DC voltage signal and the first modulation control signal that are normalized based on the DC voltage signals for the buses and the representative DC voltage signal, and to modulate the inverter circuits responsive to respective ones of the second modulation control signals. The representative DC voltage signal may represent a maximum of the DC voltages for the respective DC buses.

Abstract: An apparatus includes an inverter configured to be connected to a load, a driver having an output coupled to control terminals of transistors of the inverter and a control input configured to receive control vectors and responsively apply control signals to control terminals of the inverter, a desaturation detector configured to detect desaturation of the transistors, and a controller coupled to the control input of the driver and configured to apply at least one test vector that causes the driver to turn on selected ones of the transistors for a duration sufficient for the desaturation detector to detect desaturation of at least one of the selected transistors and to enable or inhibit further operation of the inverter responsive to the desaturation detector. The load may be a motor and the controller may be configured to apply the at least one test vector responsive to a command to start the motor.

Abstract: An apparatus includes an inverter configured to be connected to a load, a driver having an output coupled to control terminals of transistors of the inverter and a control input configured to receive control vectors and responsively apply control signals to control terminals of the inverter, a desaturation detector configured to detect desaturation of the transistors, and a controller coupled to the control input of the driver and configured to apply at least one test vector that causes the driver to turn on selected ones of the transistors for a duration sufficient for the desaturation detector to detect desaturation of at least one of the selected transistors and to enable or inhibit further operation of the inverter responsive to the desaturation detector. The load may be a motor and the controller may be configured to apply the at least one test vector responsive to a command to start the motor.

Abstract: An electrical system (2) includes a transformer (16) coupled to an AC source (6) that provides a main AC voltage, the transformer having a number of sets of primary windings (18) and secondary windings (20), and a charging module (32) structured to generate a magnetizing AC voltage. The charging module is structured to selectively provide the magnetizing AC voltage to: (i) one of the number of sets primary windings, or (ii) one of the number of sets secondary windings. The magnetizing AC voltage is such that responsive to the magnetizing AC voltage being provided to one of the sets of primary windings or one of the sets of secondary windings, one or more of the sets of primary windings will be magnetized in a manner wherein a flux of the one or more of the number of primary windings is in phase with the main AC voltage provided from the AC source.

Abstract: An interlock assembly for a bypass isolation open or closed transition ATS assembly is disclosed. The interlock assembly ensures that a switch assembly being worked upon and/or being inserted is in a neutral configuration, i.e. the switch assembly is not engaging a power source. The interlock assembly is, preferably, an electrical interlock having a control system structured to configure the switch assemblies and to monitor the configuration of the switch assemblies. That is, the switch assemblies each include a power operated, conductive, movable contact arm. The position of each contact arm is controlled, and monitored by, the control system which controls the single actuator for each contact arm.

Abstract: A medium voltage adjustable frequency drive includes an input isolation transformer having a three-phase input and a three-phase output, a converter having a three-phase input electrically connected to the three-phase output of the input isolation transformer and an output providing a direct current bus, an inverter having an input electrically connected to the output of the converter and a three-phase output, and a pre-charge circuit. The pre-charge circuit includes a ferro-resonant transformer circuit having a primary winding structured to input a low voltage and a secondary winding structured to output a medium voltage and provide a constant current source. The pre-charge circuit also includes a medium voltage diode bridge having an input receiving the medium voltage from the secondary winding of the ferro-resonant transformer circuit and an output structured to provide the constant current source to the direct current bus.

Abstract: The disclosed concept provides for a closed transition automatic transfer switch assembly having only two switch assemblies. This system utilizes a first switch assembly and a bypass switch assembly. The switch assemblies are each physically coupled to two power sources as well as the system load. The switch assemblies each include a power actuated contact arm. Each contact arm is coupled to, and in electrical communication with, the system load. Each contact arm may further be placed in one of the following configuration; a first configuration wherein the contact arm couples, and provides electrical communication between, the first source and the system load conductor, a second configuration wherein the contact arm couples, and provides electrical communication between, the second source and the system load conductor, and a neutral configuration wherein neither the first source nor the second source is coupled to, and in electrical communication with, the system load conductor.

Abstract: A medium voltage adjustable frequency drive includes an input isolation transformer having a three-phase input and a three-phase output, a converter having a three-phase input electrically connected to the three-phase output of the input isolation transformer and an output providing a direct current bus, an inverter having an input electrically connected to the output of the converter and a three-phase output, and a pre-charge circuit. The pre-charge circuit includes a ferro-resonant transformer circuit having a primary winding structured to input a low voltage and a secondary winding structured to output a medium voltage and provide a constant current source. The pre-charge circuit also includes a medium voltage diode bridge having an input receiving the medium voltage from the secondary winding of the ferro-resonant transformer circuit and an output structured to provide the constant current source to the direct current bus.

Abstract: An excitation system that includes an exciter for generating a field voltage for a rotor, a first automatic voltage regulator and a second automatic voltage regulator. The first regulator receives an output voltage of the power generation system as an input, and the second regulator receives the field voltage as an input. An output of the first regulator is provided as a second input to the second regulator. The first regulator is in selective electrical communication with the exciter through a first line conductor having first separable contacts such that an output of the first regulator may be selectively provided as an input to the exciter. The second regulator is in selective electrical communication with the exciter through a second line conductor having second separable contacts such that an output of the second regulator may be selectively provided as an input to the exciter.

Abstract: A stabilizer and synchronous electric power generator system using same that provides both power system damping and excitation limiter functionality. The stabilizer includes a processing unit and a memory storing routines executable by the processing unit. The routines are adapted to receive a voltage signal indicative of a voltage and a current signal indicative of a current output by the generator system, generate, utilizing the voltage and current signals, a power system stabilizer signal for damping oscillations and one or more excitation limiter function signals for controlling excitation level. The routines are also adapted to generate a feedback signal for the generator system by combining the power system stabilizer signal and one or more of the one or more excitation limiter function signals.

Abstract: A method controls and monitors a parallel array of a plurality of rectifier bridges each of which is adapted to convert a plurality of alternating current voltages of a plurality of alternating current phases to a voltage. The bridges include a plurality of segments each of which has an element. Each of the elements of one bridge is electrically interconnected in parallel with at least one corresponding element of at least another one of the bridges. A plurality of control signals are output to repetitively fire the elements. Conduction or non-conduction of the elements is sensed. The method determines, for the elements of the bridges, if any of the elements of one bridge and all of the at least one corresponding element of at least another one of the bridges, which are electrically interconnected in parallel, have the sensed non-conduction. An alarm signal is output responsive to the sensed non-conduction.

Abstract: A controlled rectifier bridge includes a plurality of segments each having an element responsive to a control signal, and an output having a voltage, a first current and a second current. Sensors provide sensed current values from first and second output currents from the bridge. A routine determines if the sensed current values are greater than a predetermined value. A regulator outputs the control signals to the segments in order to control current conduction within the segments. A routine determines if a circuit interrupter is open or if current is not flowing between bridge inputs and the corresponding alternating current phases. A routine disables the control signals to pairs of the segments when the sensed current values are greater than the predetermined value, and when the circuit interrupter is open or when current is not flowing between the inputs and the corresponding alternating current phases.

Abstract: A power bridge rollout service system for removing and installing a power bridge, the power bridge having a housing with an external bus assembly. The power bridge rollout service system includes a roller assembly, an enclosure assembly, and a dolly assembly. The roller assembly is structured to support the power bridge and has a plurality of wheels. The enclosure assembly has a frame assembly structured to support the power bridge and has two wheel tracks. The dolly assembly has a frame assembly, a vertical lifting device, and a plurality of wheels. The vertical lifting device and wheels are coupled to the dolly frame assembly. The vertical lifting device acts upon a work platform such as a skid table assembly. The skid table assembly has a generally flat lifting plate. The skid table assembly may be raised so that the lifting plate is at the same general height as the frame assembly wheel tracks.

Abstract: A power bridge rollout service system for removing and installing a power bridge, the power bridge having a housing with an external bus assembly. The power bridge rollout service system includes a roller assembly, an enclosure assembly, and a dolly assembly. The roller assembly is structured to support the power bridge and has a plurality of wheels. The enclosure assembly has a frame assembly structured to support the power bridge and has two wheel tracks. The dolly assembly has a frame assembly, a vertical lifting device, and a plurality of wheels. The vertical lifting device and wheels are coupled to the dolly frame assembly. The vertical lifting device acts upon a work platform such as a skid table assembly. The skid table assembly has a generally flat lifting plate. The skid table assembly may be raised so that the lifting plate is at the same general height as the frame assembly wheel tracks.

Abstract: A controlled rectifier bridge includes a plurality of segments each having an element responsive to a control signal, and an output having a voltage, a first current and a second current. Sensors provide sensed current values from first and second output currents from the bridge. A routine determines if the sensed current values are greater than a predetermined value. A regulator outputs the control signals to the segments in order to control current conduction within the segments. A routine determines if a circuit interrupter is open or if current is not flowing between bridge inputs and the corresponding alternating current phases. A routine disables the control signals to pairs of the segments when the sensed current values are greater than the predetermined value, and when the circuit interrupter is open or when current is not flowing between the inputs and the corresponding alternating current phases.

Abstract: A method for controlling a parallel array of rectifier bridges includes outputting control signals to repetitively fire bridge elements; skipping repetitive firing of the elements for one out of plural counts; sensing temperatures of the elements; averaging some of the sensed temperatures to provide a corresponding average temperature for each of the parallel bridge elements; comparing one of the sensed temperatures to the corresponding average temperature; increasing the counts when the sensed temperature of one of the elements is less than the corresponding average temperature, or decreasing the counts when the sensed temperature of the one of the elements is greater than the corresponding average temperature; and setting the counts to a first predetermined value when the sensed temperature of the one of the elements is greater than a second predetermined value above the corresponding average temperature.

Abstract: An excitation control system includes a circuit breaker, a bridge and a controller. The bridge converts AC phases from the breaker to an excitation voltage. The controller includes an output to open the breaker, a first sub-system inputting voltages corresponding to the AC phases and outputting a sensed voltage, and a second sub-system inputting the excitation voltage and outputting a sensed excitation voltage. A first function detects a trip signal and responsively outputs firing signals to the bridge to provide a negative excitation voltage. A second function determines if a threshold is greater than the sensed voltage and if the trip signal is asserted, and responsively asserts the output to open the breaker. A third function determines if the trip signal is asserted and responsively delays for a predetermined time, unless a negative threshold is greater than the sensed excitation voltage, and after the predetermined time responsively asserts the output.

Abstract: An RTD assembly includes a resistance temperature detector having two outputs, and a pair of electrical conductors including a first end and a second end. The electrical conductors are electrically connected at the second end thereof to the outputs of the resistance temperature detector. An electrically insulating polytetrafluoroethylene body, such as Teflon®, includes a closed end, a cavity and an open end. The resistance temperature detector is disposed within the cavity of the electrically insulating body and proximate the closed end thereof. The electrical conductors extend from the cavity of the electrically insulating body with the first end of the electrical conductors being external to the electrically insulating body. A cured potting compound is disposed within the cavity of the electrically insulating body and about the resistance temperature detector and the second end of the electrical conductors.

Abstract: A control system includes a rectifier bridge including a heat sink having a temperature, and also including an SCR having a gate. The SCR thermally engages the heat sink. A circuit controls the rectifier bridge through the gate of the SCR. An RTD circuit measures the temperature of the heat sink. A circuit disables gating of the SC based upon the temperature of the heat sink.