摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
An actuated seal assembly for controlling flow in a fluid path in turbomachinery comprising a seal and a seal carrier coupled to the seal is provided. A displacement apparatus is coupled to the seal carrier for positioning the seal so as to control the flow in the fluid path. In addition, a drive system is provided for powering the displacement apparatus.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
An electrical transformer includes a housing, a transformer core and winding subassembly located within the housing, and an active mount subassembly having an active mount and a controller. The active mount has a first end attached to the housing and a second end attached to the transformer core and winding subassembly. The controller has an output port connected to the active mount. The active mount cancels out (or reduces) noise-causing vibrations which come from the transformer core and winding subassembly during transformer operation.
摘要:
A circuit interruption device having a plurality of micromechanical switches mounted on a substrate in a parallel-series array. The array includes a plurality of line branches connected in parallel in a circuit line. Each of the line branches has at least two of the switches serially connected therein. The micromechanical switches each has a pair of contacts formed on the substrate, a bridging contact movably formed on the substrate, and an actuator for causing the bridging contact to move in and out of contact with the contacts. The bridging contact can be either a member slidably disposed in a channel formed on the substrate or member attached to an end of a cantilever having its other end attached to the substrate. The actuator is controlled by a trip device which is also mounted on the substrate. The trip device senses the current in the circuit line and causes the switches to open when a predetermined level of current in the line is exceeded.