Abstract: An apparatus, such as an adjustable frequency drive (AFD), includes an inverter configured to be selectively coupled to a motor in a first mode and an AC line in a second mode and a control circuit configured to operate the inverter as a motor drive in the first mode and as a power compensator in the second mode. The power compensator may provide power factor correction. The control circuit may include a scalar controller configured to control the inverter according to a voltage vs. frequency characteristic determined by a field weakening point reference and the control circuit may vary the field weakening point reference in the second mode. The inverter may have an input coupled to a DC bus and the control circuit may be configured to adjust a frequency of the inverter in the second mode to increase a voltage on the DC bus.

Abstract: An apparatus, such as a variable frequency drive (VFD), includes a rectifier, a DC bus coupled to an output of the rectifier and at least one capacitor coupled to the DC bus. The apparatus further includes a normally-conducting switch coupled to the DC bus and configured to discharge the at least one capacitor in a conducting state and a control circuit configured to control the normally-conducting switch responsive to an input to the rectifier. The control circuit may be configured to control the normally-conducting switch responsive to a voltage at the input of the rectifier. The control circuit may include a regulator circuit having an input coupled to the input of the rectifier and a driver circuit coupled to an output of the regulator circuit and configured to drive a control terminal of the normally-conducting switch.

Abstract: An apparatus, such as an adjustable frequency drive (AFD), includes an inverter configured to be selectively coupled to a motor in a first mode and an AC line in a second mode and a control circuit configured to operate the inverter as a motor drive in the first mode and as a power compensator in the second mode. The power compensator may provide power factor correction. The control circuit may include a scalar controller configured to control the inverter according to a voltage vs. frequency characteristic determined by a field weakening point reference and the control circuit may vary the field weakening point reference in the second mode. The inverter may have an input coupled to a DC bus and the control circuit may be configured to adjust a frequency of the inverter in the second mode to increase a voltage on the DC bus.

Abstract: A protection system for an electrical apparatus is disclosed. The protection system includes a baffle assembly and a coating for electrical elements exposed to arc gases. The baffle assembly includes a number of generally planar sidewalls, each sidewall including a first edge surface, a second edge surface, and a third edge surface. The sidewalls are disposed in a spaced, generally parallel configuration defining a number of channels. A first end wall is sealingly coupled to each sidewall first edge. A second end wall is sealingly coupled to each sidewall second edge. A third end wall is sealingly coupled to each sidewall third edge. The terminals of an electrical apparatus are disposed in an aligned set with one set of terminals in each channel. The channels are structured to limit the flow of arc gases across adjacent sets of terminals.

Abstract: An apparatus includes a magnetizing circuit configured to be coupled to a transformer and to selectively provide a magnetizing current to the transformer and a control circuit configured to cause the magnetizing circuit to provide the magnetizing current following disconnection of the primary winding of the transformer from the power source. The magnetizing circuit may be configured to provide the magnetizing current from a first source following disconnection of the primary winding from a second source. The transformer may include a first transformer and the apparatus may further include a second, higher impedance transformer coupled between the second source and the first transformer. In further embodiments, the magnetizing circuit may include a solid-state converter.

Abstract: An apparatus, such as a variable frequency drive (VFD), includes a rectifier, a DC bus coupled to an output of the rectifier and at least one capacitor coupled to the DC bus. The apparatus further includes a normally-conducting switch coupled to the DC bus and configured to discharge the at least one capacitor in a conducting state and a control circuit configured to control the normally-conducting switch responsive to an input to the rectifier. The control circuit may be configured to control the normally-conducting switch responsive to a voltage at the input of the rectifier. The control circuit may include a regulator circuit having an input coupled to the input of the rectifier and a driver circuit coupled to an output of the regulator circuit and configured to drive a control terminal of the normally-conducting switch.

Abstract: A system includes a variable frequency drive (VFD) comprising an inverter having an output configured to be coupled to a motor and a switch configured to couple a power source to the motor to bypass the VFD. The system further includes a control circuit configured to synchronize the VFD to the power source, to operate the switch to couple the power source and the VFD in parallel and to subsequently disable the inverter responsive to a current of the inverter. In some embodiments, a PWM frequency of the VFD may be temporarily increased when transferring the motor from the power source to the VFD.

Abstract: A protection system for an electrical apparatus is disclosed. The protection system includes a baffle assembly and a coating for electrical elements exposed to arc gases. The baffle assembly includes a number of generally planar sidewalls, each sidewall including a first edge surface, a second edge surface, and a third edge surface. The sidewalls are disposed in a spaced, generally parallel configuration defining a number of channels. A first end wall is sealingly coupled to each sidewall first edge. A second end wall is sealingly coupled to each sidewall second edge. A third end wall is sealingly coupled to each sidewall third edge. The terminals of an electrical apparatus are disposed in an aligned set with one set of terminals in each channel. The channels are structured to limit the flow of arc gases across adjacent sets of terminals.

Abstract: A protection system for an electrical apparatus is disclosed. The protection system includes a baffle assembly and a coating for electrical elements exposed to arc gasses. The baffle assembly includes a number of generally planar sidewalls, each sidewall including a first edge surface, a second edge surface, and a third edge surface. The sidewalls are disposed in a spaced, generally parallel configuration defining a number of channels. A first end wall, is sealingly coupled to each sidewall first edge. A second end wall is sealingly coupled to each sidewall second edge. A third end wall is sealingly coupled to each sidewall third edge. The terminals of an electrical apparatus are disposed in an aligned set with one set of terminals in each channel. The channels are structured to limit the flow of arc gasses across adjacent sets of terminals.

Abstract: An apparatus includes a magnetizing circuit configured to be coupled to a transformer and to selectively provide a magnetizing current to the transformer and a control circuit configured to cause the magnetizing circuit to provide the magnetizing current following disconnection of the primary winding of the transformer from the power source. The magnetizing circuit may be configured to provide the magnetizing current from a first source following disconnection of the primary winding from a second source. The transformer may include a first transformer and the apparatus may further include a second, higher impedance transformer coupled between the second source and the first transformer. In further embodiments, the magnetizing circuit may include a solid-state converter.

Abstract: A system includes a variable frequency drive (VFD) comprising an inverter having an output configured to be coupled to a motor and a switch configured to couple a power source to the motor to bypass the VFD. The system further includes a control circuit configured to synchronize the VFD to the power source, to operate the switch to couple the power source and the VFD in parallel and to subsequently disable the inverter responsive to a current of the inverter. In some embodiments, a PWM frequency of the VFD may be temporarily increased when transferring the motor from the power source to the VFD.

Abstract: A protection system for an electrical apparatus is disclosed. The protection system includes a baffle assembly and a coating for electrical elements exposed to arc gasses. The baffle assembly includes a number of generally planar sidewalls, each sidewall including a first edge surface, a second edge surface, and a third edge surface. The sidewalls are disposed in a spaced, generally parallel configuration defining a number of channels. A first end wall, is sealingly coupled to each sidewall first edge. A second end wall is sealingly coupled to each sidewall second edge. A third end wall is sealingly coupled to each sidewall third edge. The terminals of an electrical apparatus are disposed in an aligned set with one set of terminals in each channel. The channels are structured to limit the flow of arc gasses across adjacent sets of terminals.

Abstract: A medium voltage drive and control system includes a dual bus configuration including an AC bus and a DC bus, a converter module connected to the AC bus and structured to receive AC power from the AC bus and convert the AC power to DC power, a DC link module coupled to the converter module and to the DC bus, wherein the DC link module is structured to store the DC power and provide the DC power to the DC bus, and a plurality of inverter modules, each inverter module being coupled to the DC bus and being structured to receive at least a portion of the DC power from the DC bus and convert the at least a portion of the DC power to quasi-sinusoidal AC output power for provision to a load associated with the inverter module.

Abstract: An adjustable frequency drive including a number of power modules and a heat management system is provided. Each of the number of power modules includes a number of inverters. Each inverter includes a number of power poles. The heat management system includes a housing assembly, a first heat management assembly, and a second heat management assembly. The housing assembly defines a power module enclosure and a liquid cooling assembly enclosure. The first heat management assembly is substantially disposed in the power module enclosure. The second heat management assembly is not substantially disposed in the power module enclosure.

Abstract: An electrical system includes a transformer structured to be selectively coupled to an AC source that provides a main AC voltage, the transformer having a number of sets of primary windings and a number of sets of secondary windings, and a charging module 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 number of sets of primary windings or one of the number of sets of secondary windings, one or more of the number of 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: A motor drive system includes a step down phase shifting isolation transformer structured to receive medium voltage AC power from an AC bus and convert the medium voltage AC power to tow voltage AC power, a converter structured to receive the low voltage AC power and convert the low voltage AC power to DC power and output the DC power to a DC bus, and a tow voltage inverter structured to receive the DC power from the DC bus and convert the DC power to a second low voltage AC power.

Abstract: An adjustable frequency drive including a number of power modules and a heat management system is provided. Each of the number of power modules includes a number of inverters. Each inverter includes a number of power poles. The heat management system includes a housing assembly, a first heat management assembly, and a second heat management assembly. The housing assembly defines a power module enclosure and a liquid cooling assembly enclosure. The first heat management assembly is substantially disposed in the power module enclosure. The second heat management assembly is not substantially disposed in the power module enclosure.

Abstract: A housing assembly, structured to enclose a plurality of electrical components and flexible cables, each the electrical component coupled at least one other electrical component or to an input device by the cables, includes a plurality of mounting plate members and a plurality of vertical walls. The plurality of mounting plate members includes at least a bottom mounting plate member and at least one movable mounting plate member. Each mounting plate structured to support one or more electrical components. The plurality of vertical walls include a front wall coupled to, and extending generally perpendicular to, the base plate member, a first side wall coupled to, and extending generally perpendicular to, the base plate member, a second side wall coupled to, and extending generally perpendicular to, the base plate member, a back wall coupled to, and extending generally perpendicular to, the base plate member.