Abstract:
In one embodiment, a variable frequency drive system includes a main contactor, a variable frequency drive, a charging module structured to generate a magnetizing AC voltage, wherein the charging module is structured to selectively provide the magnetizing AC voltage to a transformer of the variable frequency drive, and a sensing and control circuit having a number of sensors operably associated with the variable frequency drive. The sensing and control circuit is structured to detect a short circuit condition in the variable frequency drive when the magnetizing AC voltage is provided to the transformer based on an output of at least one of the number of sensors, and responsive thereto prevent the main contactor from being closed and thereby prevent the main AC voltage from being provided to the transformer.
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:
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 power pole inverter is provided. The power pole inverter includes a housing assembly, a capacitor assembly, a number of arm assemblies, a number of heat sinks, and a support assembly. The housing assembly includes a number of sidewalk. The housing assembly sidewalls defining an enclosed space. The capacitor assembly is coupled to the housing assembly. Each arm assembly includes a plurality of electrical components and a number of electrical buses. Each the electrical bus includes a body with terminals, each the terminal structured to be coupled to, and in electrical communication with, the capacitor assembly, each arm assembly including a neutral terminal. Each arm assembly is coupled to, and in electrical communication with, the capacitor assembly. The support assembly includes a non-conductive frame assembly. The support assembly is structured to support each the heat sink in isolation.
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 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 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 power pole inverter is provided. The power pole inverter includes a housing assembly, a capacitor assembly, a number of arm assemblies, a number of heat sinks, and a support assembly. The housing assembly includes a number of sidewalk. The housing assembly sidewalls defining an enclosed space. The capacitor assembly is coupled to the housing assembly. Each arm assembly includes a plurality of electrical components and a number of electrical buses. Each the electrical bus includes a body with terminals, each the terminal structured to be coupled to, and in electrical communication with, the capacitor assembly, each arm assembly including a neutral terminal. Each arm assembly is coupled to, and in electrical communication with, the capacitor assembly. The support assembly includes a non-conductive frame assembly. The support assembly is structured to support each the heat sink in isolation.