Abstract: A controller (28) for a doubly fed induction generator (12,20) adjusts control signals to a rotor side converter (24) and line side converter (22) to adjust rotor current when a voltage transient on a utility grid (10) occurs, so that the doubly fed induction generator can ride through the transient. The controller can also turn off the transistors of the rotor side converter (24) to reduce rotor current and/or activate a crowbar (42) to reduce the voltage of the DC link (26) connecting the converters (22, 24) when significant voltage transients occur on the grid (10). This permits continued operation of the DFIG system without disconnecting from the grid.

Abstract: A method and apparatus are disclosed for converting wind generated electricity to constant frequency electricity for supplying it to a utility grid. The disclosed system and method uses a wind turbine generator having a doubly fed induction generator. Above the synchronous speed of the generator, the electricity from the rotor is converted to direct current (dc) electricity and the dc electricity is converted back to alternating current (ac) electricity at a fixed unity power factor. Below synchronous speed, electricity flows to the rotor from the utility grid also at a fixed unity power factor. The current of the ac electricity is adjusted to be in phase with the utility grid voltage, wherein the ac electricity is maintained substantially at unity power factor.

Abstract: A pulsating spray nozzle is particularly useful in an irrigation lavage for medical or veterinary use in delivering pulsating streams of liquid for cleansing wounds. The spray nozzle is designed to provide a steady operation over a wide range of flow rates. The nozzle comprises a hollow portable housing having an inlet connectable to a source of fluid. The nozzle housing has an end closure member providing an end wall having a plurality of fluid discharge orifices located symmetrically around the longitudinal axis of the housing. A rotary valve member is positioned in the housing for rotation along the surface of the end wall to control flow of liquid through the orifices therein. The rotary valve member comprises an arcuate valve plate supported on and integral with a plurality of radially extending vanes.

Abstract: A hygienic device has a pump for propelling liquid in a flow of pulses, a motor for driving the pump, a switch for supplying power to the motor and means for delivering the propelled liquid to a point of use. A control enables adjustment of the pressure of the delivered liquid. The switch is formed as part of the motor winding assembly and therewith is effectively encapsulated. The pump includes a piston in one end of which is a recess defining a resilient spherical seat and which cooperates with a spherical bearing formed on one end of a piston rod. The control has a valved bypass arrangement wherein various stops and abutments cooperate to permit accurate determination of high and low pressure adjustment during assembly. A rotor within the motor has a cylindrical bore with longitudinal lugs that interfit with ribs on a bearing member that is pressed into the bore. Other features, such as a tilt-out nozzle storage shelf, are included.