Abstract: A lubrication system for a main bearing positioned around a main shaft of a wind turbine includes a seal ring positioned around the shaft adjacent to the bearing, at least one gear adjacent to the seal ring, a mechanical lubricant pump arranged to engage the at least one gear, and at least one lubricant for providing lubrication to the bearing. Thus, as the shaft rotates, the gear(s) drives the lubricant pump such that the pump continuously provides the lubricant to the bearing so long as the shaft is rotating.

Abstract: A yaw system for a wind turbine can have a yaw bearing with an outer bearing ring, an inner bearing ring, and a plurality of yaw rollers rotationally disposed between the outer and inner bearing rings so as to allow relative motion between the outer and inner bearing rings. A bi-directional braking assembly having an outer clutch ring attached to the outer bearing ring, an inner clutch ring attached to the inner bearing ring, and a plurality of brake rollers rotationally and slidably disposed between the inner clutch ring and at least one locking ramp adjacent the outer clutch ring. A plurality of spring members can extend from either ring projections or activation projections to each brake roller. An activation ring can slidably position the plurality of brake rollers into one of a locked position or unlocked position to prevent yaw rotation in an undesired direction.

Abstract: A method for replacing an existing radial seal positioned around a shaft and adjacent to a bearing includes providing at least one spacer in a seal cavity of the existing radial seal. The method also includes removing a cover of the existing radial seal. The method further includes removing the at least one spacer. In addition, the method includes removing the existing radial seal from around the shaft. Moreover, the method includes replacing the existing radial seal with a new radial seal. Further, the method includes moving the spacer(s) from a first side of the seal cavity to an opposing, second side of the seal cavity to provide a new sealing location for the new radial seal. Thus, the method also includes securing the cover adjacent to the new radial seal.

Abstract: A yaw system for a wind turbine can have a yaw bearing with an outer bearing ring, an inner bearing ring, and a plurality of yaw rollers rotationally disposed between the outer and inner bearing rings so as to allow relative motion between the outer and inner bearing rings. A bi-directional braking assembly having an outer clutch ring attached to the outer bearing ring, an inner clutch ring attached to the inner bearing ring, and a plurality of brake rollers rotationally and slidably disposed between the inner clutch ring and at least one locking ramp adjacent the outer clutch ring. A plurality of spring members can extend from either ring projections or activation projections to each brake roller. An activation ring can slidably position the plurality of brake rollers into one of a locked position or unlocked position to prevent yaw rotation in an undesired direction.

Abstract: A lubrication system for a main bearing positioned around a main shaft of a wind turbine includes a seal ring positioned around the shaft adjacent to the bearing, at least one gear adjacent to the seal ring, a mechanical lubricant pump arranged to engage the at least one gear, and at least one lubricant for providing lubrication to the bearing. Thus, as the shaft rotates, the gear(s) drives the lubricant pump such that the pump continuously provides the lubricant to the bearing so long as the shaft is rotating.

Abstract: A system is provided that includes a cavity ring-down spectrometer and a processor. The spectrometer is configured to pass, through a cavity resonator, a modulated, continuous-wave electromagnetic signal at each of one or more selectable, transmission frequencies in the Terahertz region of the electromagnetic spectrum. The spectrometer includes a transmitter that, with the cavity resonator, is configured so as to excite a single resonant mode of the cavity resonator. The processor is configured to receive a measurement of the passed portion of the modulated electromagnetic signal, and determine a phase shift of the modulated electromagnetic signal based upon the measurement. The processor is then configured to calculate a ring-down time of the cavity resonator as a function of the phase shift.

Abstract: A system for suppressing noise by frequency dither includes a transmitter, receiver and a frequency dither circuit, as well as a cavity along a propagation path of the electromagnetic signal between the transmitter and the receiver. The transmitter is configured to transmit an electromagnetic signal to the receiver at each of one or more selectable frequencies. The frequency dither circuit is configured to apply a frequency dither to the electromagnetic signal transmitted from the transmitter to the receiver at each of the selectable frequencies. In this regard, the applied frequency dither has a span having been selected as a function of a minimum frequency period of an expected standing wave in the system, and a rate having been selected as a function of a signal processing bandwidth for sampling a frequency spectrum including the selectable frequencies.

Abstract: A system is provided that includes a cavity ring-down spectrometer and a processor. The spectrometer is configured to pass, through a cavity resonator, a modulated, continuous-wave electromagnetic signal at each of one or more selectable, transmission frequencies in the Terahertz region of the electromagnetic spectrum. The spectrometer includes a transmitter that, with the cavity resonator, is configured so as to excite a single resonant mode of the cavity resonator. The processor is configured to receive a measurement of the passed portion of the modulated electromagnetic signal, and determine a phase shift of the modulated electromagnetic signal based upon the measurement. The processor is then configured to calculate a ring-down time of the cavity resonator as a function of the phase shift.

Abstract: A system includes a transmitter is configured to transmit an electromagnetic signal to a receiver, which is configured to receive the electromagnetic signal and another electromagnetic signal for mixing therewith. Propagation paths of the signals to the transmitter and receiver include a first propagation path of the electromagnetic signal to the transmitter, and a second propagation path of the other electromagnetic signal to the receiver. The arrangement, which is located along either or each of the propagation paths of signals to the transmitter and receiver, is configured to alter the length of a respective propagation path. And the processor configured to recover an amplitude and phase of the transmitted electromagnetic signal, including being configured to receive a sequence of samples of the received electromagnetic signal, and Discrete Fourier Transformation process the sequence of samples.

Abstract: A system includes a transmitter is configured to transmit an electromagnetic signal through a sample cell (including a sample medium) to a receiver, which is configured to receive the electromagnetic signal and another electromagnetic signal for mixing therewith. Propagation paths of the signals to the transmitter and receiver include a first propagation path of the electromagnetic signal to the transmitter, and a second propagation path of the other electromagnetic signal to the receiver. The arrangement, which is located along either or each of the propagation paths of signals to the transmitter and receiver, is configured to alter the length of a respective propagation path. And the processor configured to recover an amplitude and phase of the transmitted electromagnetic signal, and calculate a complex index of refraction of the sample medium as a function of the amplitude and phase of the transmitted electromagnetic signal.

Abstract: A system includes a transmitter is configured to transmit an electromagnetic signal through a sample cell (including a sample medium) to a receiver, which is configured to receive the electromagnetic signal and another electromagnetic signal for mixing therewith. Propagation paths of the signals to the transmitter and receiver include a first propagation path of the electromagnetic signal to the transmitter, and a second propagation path of the other electromagnetic signal to the receiver. The arrangement, which is located along either or each of the propagation paths of signals to the transmitter and receiver, is configured to alter the length of a respective propagation path. And the processor configured to recover an amplitude and phase of the transmitted electromagnetic signal, and calculate a complex index of refraction of the sample medium as a function of the amplitude and phase of the transmitted electromagnetic signal.

Abstract: A system for suppressing noise by frequency dither includes a transmitter, receiver and a frequency dither circuit, as well as a cavity along a propagation path of the electromagnetic signal between the transmitter and the receiver. The transmitter is configured to transmit an electromagnetic signal to the receiver at each of one or more selectable frequencies. The frequency dither circuit is configured to apply a frequency dither to the electromagnetic signal transmitted from the transmitter to the receiver at each of the selectable frequencies. In this regard, the applied frequency dither has a span having been selected as a function of a minimum frequency period of an expected standing wave in the system, and a rate having been selected as a function of a signal processing bandwidth for sampling a frequency spectrum including the selectable frequencies.

Abstract: A system includes a transmitter is configured to transmit an electromagnetic signal to a receiver, which is configured to receive the electromagnetic signal and another electromagnetic signal for mixing therewith. Propagation paths of the signals to the transmitter and receiver include a first propagation path of the electromagnetic signal to the transmitter, and a second propagation path of the other electromagnetic signal to the receiver. The arrangement, which is located along either or each of the propagation paths of signals to the transmitter and receiver, is configured to alter the length of a respective propagation path. And the processor configured to recover an amplitude and phase of the transmitted electromagnetic signal, including being configured to receive a sequence of samples of the received electromagnetic signal, and Discrete Fourier Transformation process the sequence of samples.

Abstract: A system for processing signals includes a receiver assembly for receiving a signal. The signal has a sample component with a sample electric field and a sample polarization, and has a reference component with a reference electric field and a reference polarization. The receiver assembly includes an analyzer for polarimetrically processing the signal, including differencing the signal to generate a difference electric field proportional to the difference of the sample and reference electric fields. By polarimetrically differencing the signal, the analyzer reduces the magnitude of the common-mode signal at the difference signal receiver. The receiver assembly includes an electric-field detector for measuring the difference electric field such that the reduction in common-mode amplitude decreases the noise equivalent power of the electric-field detector.

Abstract: A system for processing signals includes a receiver assembly for receiving a signal. The signal has a sample component with a sample electric field and a sample polarization, and has a reference component with a reference electric field and a reference polarization. The receiver assembly includes an analyzer for polarimetrically processing the signal, including differencing the signal to generate a difference electric field proportional to the difference of the sample and reference electric fields. By polarimetrically differencing the signal, the analyzer reduces the magnitude of the common-mode signal at the difference signal receiver. The receiver assembly includes an electric-field detector for measuring the difference electric field such that the reduction in common-mode amplitude decreases the noise equivalent power of the electric-field detector.

Abstract: A star tracker 10 of an attitude control system 8 on board a spacecraft 9 is positioned so that the tracker's line-of-sight vector 12 intersects the origin of the reference axis but is askew from any reference axis of the spacecraft. The attitude control system transforms the dam from a star tracker reference coordinate system to a spacecraft reference coordinate system so as to allow control of the attitude of the spacecraft without modification of existing equipment.

Abstract: A method and apparatus for tracking a light source in a transient event rich environment locks on to a light source incident on a field-of-view 1 of a charge-coupled-device (CCD) array 6, validates the permanence of said light source and transmits data relating to the brilliance and location of said light source if said light source is determined to be permanent.

Abstract: Apparatus for detecting and determining the direction of arrival of optical radiation. The apparatus includes a first mask having one or more slit apertures, a binary encoding mask which combines the functions of angle sensing and digitizing using a so-called gray encoding scheme, and interdigitated detector(s) to produce differential electrical signals, and output processing electronics for providing a digital code or word corresponding to the angle-of-arrival of the incident radiation.

Abstract: This invention relates to unequal path interferometers which are adapted, among other possible uses, for use in detecting coherent radiation as from a laser in a packet of radiation including incoherent background radiation, which includes an unequal optical path length interferometer of the type in which portions of the radiation impinging on the interferometric component are caused to be recombined after travelling two different optical paths; the optical paths differing in length by an amount substantially greater than the coherence length of the non-coherent radiation but substantially less than the coherence length of the coherent radiation; the unequal optical path length interferometric component including a crystalline cell having anisotropic properties; circuitry for applying an ultrasonic sound wave to the crystalline cell to vary the effective index of refraction of the crystalline cell in a preselected systematic manner; a detector for detecting the intensity of the recombined portions and produci

Abstract: A non-imaging detector for directly measuring the angle of incidence of irradiation in one plane from an illuminating source. The detector includes a slit mask that transmits narrow lines of irradiation across an array of detectors closely underlying the slit mask. The detectors are configured to generate photocurrents whose ratio exponentially increase as the irradiation lines through the slits move along the array in response to changes in angle of incidence. The detectors are configured according to an exponential formula so that adjacent rows of detectors produce photocurrents so that the photocurrent log difference from adjacent rows will result in a signal directly proportional to incidence angle when subtracted by associated circuitry.