Abstract: A system includes a self-servo-write (SSW) module, a read module, and a write module. The SSW module writes servo spirals on a magnetic medium of a hard disk drive (HDD) via a write head of the HDD. The read module reads the servo spirals via a read head of the HDD and generates read signals. The write module writes non-servo data on the magnetic medium via the write head based on the read signals before the SSW module writes servo wedges on the magnetic medium.

Abstract: An apparatus (500) for fatigue testing elongate test articles (404) including wind turbine blades through forced or resonant excitation of the base (406) of the test articles (404). The apparatus (500) includes a testing platform or foundation (402). A blade support (410) is provided for retaining or supporting a base (406) of an elongate test article (404), and the blade support (410) is pivotally mounted on the testing platform (402) with at least two degrees of freedom of motion relative to the testing platform (402). An excitation input assembly (540) is interconnected with the blade support (410) and includes first and second actuators (444, 446, 541) that act to concurrently apply forces or loads to the blade support (410). The actuator forces are cyclically applied in first and second transverse directions. The test article (404) responds to shaking of its base (406) by oscillating in two, transverse directions (505, 507).

Abstract: An apparatus (100) for fatigue testing test articles (104) including wind turbine blades. The apparatus (100) includes a test stand (110) that rigidly supports an end (106) of the test article (104). An actuator assembly (120) is attached to the test article (104) and is adapted for substantially concurrently imparting first and second forcing functions in first and second directions on the test article (104), with the first and second directions being perpendicular to a longitudinal axis. A controller (130) transmits first and second sets of displacement signals (160, 164) to the actuator assembly (120) at two resonant frequencies of the test system (104). The displacement signals (160, 164) initiate the actuator assembly (120) to impart the forcing loads to concurrently oscillate the test article (104) in the first and second directions. With turbine blades, the blades (104) are resonant tested concurrently for fatigue in the flapwise and edgewise directions.

Abstract: A system (1100) for fatigue testing wind turbine blades (1102) through forced or resonant excitation of the base (1104) of a blade (1102). The system (1100) includes a test stand (1112) and a restoring spring assembly (1120) mounted on the test stand (1112). The restoring spring assembly (1120) includes a primary spring element (1124) that extends outward from the test stand (1112) to a blade mounting plate (1130) configured to receive a base (1104) of blade (1102). During fatigue testing, a supported base (1104) of a blade (1102) may be pivotally mounted to the test stand (1112) via the restoring spring assembly (1120). The system (1100) may include an excitation input assembly (1140) that is interconnected with the blade mounting plate (1130) to selectively apply flapwise, edgewise, and/or pitch excitation forces.

Abstract: Insulating ribs are formed into one or more portions of a housing that encloses circuitry of an electrical device. Components mounted on a board are separated according to whether they are related to a primary side of a power transformer or a secondary side. Primary related components are typically mounted on the primary side of an isolation slot formed into a circuit board and components related to the secondary are mounted on the other side. The insulating ribs are strategically placed to protrude through the slots when circuit board is mounted to the housing portion. Thus, when the housing portion is joined to another housing portion, which also may include insulating ribs strategically placed, the ribs increase the breakdown voltage of the boundary.

Abstract: A cleaning system comprises a first type of scrubber head having a first type of attachment mechanism and a second type of attachment mechanism and a second type of scrubber head having the first type of attachment mechanism and the second type of attachment mechanism. A first type of cleaning pad may be releasably mounted to either the first scrubber head or the second scrubber head using the first attachment mechanism. A second type of cleaning pad may be releasably mounted to either the first scrubber head or the second scrubber head using the second attachment mechanism. One scrubber head comprises a base comprising a first section and a flexible section. An assembly is movably mounted on the base such that the assembly may be moved to make the flexible section active.

Abstract: A system includes a self-servo-write (SSW) module, a read module, and a write module. The SSW module writes servo spirals on a magnetic medium of a hard disk drive (HDD) via a write head of the HDD. The read module reads the servo spirals via a read head of the HDD and generates read signals. The write module writes non-servo data on the magnetic medium via the write head based on the read signals before the SSW module writes servo wedges on the magnetic medium.