Abstract: X-ray tube noise is reduced by coupling the stator mass to the neck section of the glass vacuum tube so that vibrations are dissipated by the stator and not transmitted to the bulk of the vacuum tube. The coupling is accomplished with a non-magnetic sealing material such as an epoxy sealant. The sealant will generally fill the gap between the stator and the neck section of the vacuum tube. Alternatively, the coupling can be done with a mechanical clamping device.

Abstract: System and method for detecting the occurrence, location and depth of a crack in the rotor of a turbine-generator. The location and depth of a crack are determined by monitoring the fundamental and histogram harmonic components of vibrations at certain predetermined points along the length of the rotor. The histogram harmonic components are normalized relative to the fundamental component, and the normalized histogram harmonic components are monitored to determine the location of the crack. The unnormalized histogram harmonic components are analyzed to determine the depth of the crack. The occurrence of a crack is detected by monitoring the amplitude and phase of rotor vibrations during an accel or decel operation to detect harmonic resonances which are characteristic of a crack in the rotor. The amplitude and phase data is filtered to eliminate spurious data, and it is interpolated to provide baseline and current data at matching speed points.

Abstract: Each bearing of an aligned line-shaft has vibration responses which differ from the vibration responses of a misaligned system in which at least one of the bearings is statically displa=ced. Computed static displacement values for each bearing are derived from the equation of motion of the system employing mass, stiffness and damping coefficients of the system. The static displacement value of each bearing is computed from the vibration responses of all of the bearings. Accelerometers sense the vibration response of each bearing. A computer computes the magnitude of misalignment of each bearing from the sensed responses. The computed results provide an indication of the magnitude of static displacement of each bearing of the system causing the sensed vibration response.

Abstract: Objectionable noise in a rotary compressor is reduced by placing cavities in the sliding vane and/or the rolling piston. The cavities are used to change the local compliance of surfaces which impact one another to generate the objectionable noise. The change in the compliance of impacting surfaces is used to change the frequency of the noise generated by the impacting surfaces.

Abstract: A Helmholtz resonator is used in communication with the compression chamber of a rotary compressor in order to attenuate noise. The resonator concentrates the attenuation of noise in a frequency band around 4 kHz corresponding to the concentration of noise produced by a particular rotary compressor, this band also corresponding to the frequencies which the human ears are most sensitive to. The resonator branches off from the discharge port in an end wall of the compressor. The resonantor uses an easily machined cylindrical resonance cavity on the surface of the end wall, the resonance cavity also being bounded on one side by a cylindrical wall of the rotary compressor. The resonator significantly reduces the noise in a rotary compressor of a specific type commonly used for compressing refrigerant gases in a refrigerator.

Abstract: Axial cracks in the rotor assembly of a variety of rotating machinery are detected while the rotor is being rotated, by sensing mechanical vibrations of the rotor at a location along the length thereof to produce a corresponding rotor vibration signal. A background vibration signal representing the vibration response at an earlier time is provided, as well as a monitor vibration signal representing the vibration response of the rotor at the time the monitor signal is obtained. A speed-dependent first harmonic difference signal is found by vectorially subtracting the first harmonic of the background vibration signal from the first harmonic of the monitor vibration signal.

Abstract: A high speed contact driver for use in an electrical circuit interrupter includes a pair of series-connected, elongate and generally opposing electrical conductors bowed in predetermined, generally opposing contours. These conductors are connected to a bridging electrical contact which is normally biased into a bridging position between a pair of stationary contacts. Pulse generating means are provided for applying a current pulse of predetermined magnitude to the electrical conductors. In response to this current pulse, these electrical conductors electromagnetically repulse each other and drive the bridging contact out of bridging position between the stationary contacts.

Abstract: A method is disclosed for detecting incipient cracks in the rotor of a turbine-generator while the turbine-generator is on-line operating under normal conditions. Vibration signature analysis is performed on a set of difference signals produced by superposing and subtracting corresponding enhanced background and foreground vibration signals. Each enhanced vibration signal is created by superposing and summing an integral number of vibration signal segments, each segment corresponding to one revolution of the rotor. An incipient crack is manifested principally by the appearance and increase in relative amplitude of signal harmonics at twice the rotational speed of the rotor. The method of the invention is sufficiently sensitive to detect cracks having a depth on the order of less than one-percent the diameter of the rotor.

Abstract: This actuator comprises a fluid motor having a piston, a breaker-opening space at one side of the piston, and a breaker-closing space at its opposite side. An accumulator freely communicates with the breaker-opening space for supplying pressurized fluid thereto during a circuit breaker opening operation. The breaker-opening space and the breaker-closing space are connected by an impeded flow passage. A pilot valve opens to allow the pressurized liquid in the breaker-closing space to flow to a back chamber of a normally closed main valve to cause the main valve to be opened during a circuit breaker opening operation to release the pressurized liquid from the breaker-closing space. An impeded passage affords communication between the back chamber and a sump located on the opposite side of the main valve from the back chamber. The pilot valve and impeded passage allow rapid opening of the main valve with pressurized liquid from the breaker closing side of the piston.

Abstract: A method is disclosed by which incipient cracks are detected in the rotor of a fluid powered turbine while the turbine is on-line and running under substantially normal load. In a preferred form of the invention, vibrations are monitored in the rotor and signature analysis of the normal background vibration pattern is obtained to establish the spectral content of the normal vibration signal. The turbine rotor is then transitorily perturbed, preferably by changing the temperature of the motive fluid (steam temperature is changed for example in a steam driven turbine), and the signature analysis is again performed to determine changes in the vibration pattern. An increase in the amplitude of the fundamental frequency and the appearance and increase in amplitude of higher harmonics following rotor perturbation is indicative of the presence and size of a crack in the rotor.

Abstract: This circuit breaker comprises a plurality of a vacuum-type circuit interrupters, each having a movable contact rod. A common operating device for the interrupters comprises a linearly-movable operating member. The interrupters are mounted at one side of the operating member with their movable contact rods extending in a direction generally toward the operating member. Means is provided for mechanically coupling the operating member to the contact rods, and this means comprises a plurality of insulating operating rods, each connected at one end to the operating member and at its opposite end to one of the movable contact rods. The operating rods are of substantially equal length and have longitudinal axes that converge and intersect at substantially a common point.

Abstract: A high current interrupter is enclosed in a sealed enclosure having a pair of axially disposed contacts therein, one stationary and one movable relative thereto. An array of rods or electrodes is mounted near each end of the enclosure, the rods extending toward the opposite end of the enclosure and terminating at a free end short of the opposite end. The arrays are similar in pattern and thus each rod lies between and is spaced from rods extending from the opposite enclosure end. Each array of rods is mounted in a pair of thin spaced mounting plates, which are connected together near the centers thereof. The plates engage the rods near the end opposite the free end, both plates being electrically conductive and being connected electrically to one of the two electrical contacts within the enclosure.

Abstract: This operating system comprises a fluid motor having a piston, a breaker-opening space at one side of the piston, and a breaker-closing space at its opposite side. An accumulator freely communicates with the breaker-opening space for supplying pressurized fluid thereto during a circuit-breaker opening operation. A normally-closed valve located on the breaker-closing-side of the piston is openable to release liquid from the breaker-closing space so that pressurized liquid in the breaker-opening space can drive the piston in an opening direction. Means is provided for restoring the valve to its closed position following the circuit-breaker opening operation. An impeded passage affords communication between the accumulator and the breaker-closing space to allow pressurized liquid to flow from the accumulator to the breaker-closing space and develop a pressure therein substantially equal to accumulator pressure when the valve is restored to closed position following breaker-opening.

Abstract: This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A vent is located hydraulically between the actuating space and the valve for affording communication between said actuating space and a low pressure region.Flow control means is provided for restricting leakage through said vent to a rate that prevents said leakage from substantially detracting from the development of pressure within said actuatng space during the period from initial opening of the valve to the time when said piston has moved through most of its opening stroke.