Abstract: An electrical switching device having a plurality of parallel coupled IGBTs is provided. The electrical switching device balances electrical currents in each of the IGBTs that are supplied to a load.

Abstract: A method for coupling an energy storage system to a variable energy supply system includes providing an energy storage system including at least one Vanadium redox battery and at least one battery charge controller. The method also includes electrically coupling the at least one battery charge controller to the variable energy supply system such that the at least one battery is configured to supply a substantially consistent energy output during fluctuating energy loads of the energy supply system.

Abstract: A system and method for power control in wind turbines are provided. The method includes switching a plurality of switching devices in a power conversion component of the wind turbine system in a normal switching mode to provide power flow through the power conversion component. The method further includes switching the plurality of switches devices in the power conversion component of the wind turbine system in a short circuit switching mode to prevent power flow through the power conversion component.

Abstract: Methods and systems for current sharing between power semiconductors in an assembly are provided. The power semiconductor assembly includes a plurality of power semiconductors, each comprising at least one output conductor, the plurality of output conductors are electrically coupled together in parallel, an output bus network configured to transpose the output conductors such that magnetic fields causing a current output imbalance between the plurality of power semiconductors are substantially canceled.

Abstract: A method and transfer circuit topology for a redundant power converter for switching a load between power conversion circuits in a redundant system. The transfer circuit topology includes a first contactor and a second contactor each having an input coupled to a source and an output coupled to a controlled commutating current path. The controlled commutating current path is coupled to the load for switching between the redundant power converters without interrupting current to the load.

Abstract: A drill bit for boring a bore hole in an earthen formation comprises: a bit body having a pin end, a cutting end and a longitudinal bit axis and including at least two legs extending from the cutting end, each of the legs including a bearing that rotatably supports a cutter cone. The bit body further includes a fluid flow system, including a flowway in said pin end that is in fluid communication with at least one exit port in the cutting end, the exit port being defined by a nozzle boss and disposed adjacent one of the legs. Each of the legs includes a leading side surface, a trailing side surface, and a center panel, and at least one of said legs is asymmetric such that its trailing side surface is larger than its leading side surface. The present bit can also include a lubricant system that has its opening in the trailing side of the leg, and can further include various wear resistant coatings and inserts on its surface.

Abstract: A first embodiment of a radially disposed thrust bearing assembly for rotary cone rock bits consists of a first non-rotating radially disposed steel thrust bearing disc and an adjacent, carbide thrust bearing disc. One of the thrust bearing discs is pressed into a disc retention socket formed in the end of a spindle bearing extending from the end of a main axially aligned bearing cantilevered from a leg of the bit and the other thrust bearing disc is pressed into a disc retention socket formed in the rotary cone. An edge of the carbide disc is formed with large valleys and peaks, the robust undulations resist cracking when the carbide thrust bearing disc is pressed into its respective socket. Unique air passages and channels are formed in the main and spindle bearings to direct cooling air to the thrust bearing discs.

Abstract: A radially disposed thrust bearing assembly for air cooled and lubricated mining type rotary cone rock bits consists of a first non-rotating radially disposed steel thrust bearing disc and an apposed, non-rotating carbide thrust bearing disc. One of the thrust bearing discs is pressed into a disc retention socket formed in the end of a spindle bearing extending from the end of a main axially aligned bearing cantilevered from a leg of the bit and the other thrust bearing disc is pressed into a disc retention socket formed in the rotary cone. An edge of the carbide disc is formed with large valleys and peaks, the robust undulations resist cracking when the carbide thrust bearing disc is pressed into its respective socket. Unique air passages and channels are formed in the main and spindle bearings to direct cooling air to the apposed thrust bearing discs.