Abstract:
The present disclosure relates to a system to compensate for mechanical forces on a rotating rotor of an electric machine, to a method for compensating mechanical forces on a rotating rotor of an electric machine, and to a use of a corresponding system. Disclosed is a system for compensating torsions at a rotating rotor. The system includes at least one measuring device for measuring specific properties of the rotor, an analyser unit for analysing the measurement data of the measuring device, a compensation means for compensating the torsions at the rotor, the compensation means comprise a power supply unit generating a signal adapted in amplitude and frequency to the measured properties of the rotor, and to apply the generated signal to the rotor, and the power supply unit is a frequency converter.
Abstract:
A method and apparatus for generating and measuring a torsional wave in a rod, shaft or pipe using magnetostriction are provided. The magnetostrictive transducer includes at least one strip attached to a predetermined position of a rod member, an insulator disposed around the strip, a coil wound around the insulator, and magnets providing a bias magnetic field to the strip, wherein a plurality of strips are attached to the rod member at predetermined intervals in a circumferential direction, and one pole of the magnet is close to an end of a first strip among the plurality of strips, and another pole of the magnet is close to an end of a second strip among the plurality of strips.
Abstract:
A method and an apparatus 10 for discerning the torsional mode response of a portion of a vehicle 12, such as but not limited to a drivetrain assembly, comprising a driveshaft 52, transmission assembly 50, and shaft 14, by the use of signals generated from a dynamometer 72 and pseudo-randomly varying signals which are specified by a pseudorandom waveform generator 94 and which are modified by a previously calculated error signal.
Abstract:
A turntable having a food of solid or liquid put in a container is rotated during a predetermined time period and then the rotation of the turntable is suspended. After the turntable is suspended, an amplitude of vibration of the turntable is detected by a vibration sensor, and when the amplitude of vibration is a predetermined value or more, the food is determined liquid, on the other hand, when the amplitude of vibration is smaller than the predetermined value, the food is determined to be solid.
Abstract:
An apparatus for measuring torsional vibrations of rotating machinery is provided. A wheel having a plurality of spaced apart teeth is connected to the rotating machinery. A sensor detects the speed of wheel rotation and responsively produces a speed signal that has a frequency proportional to the rotational wheel speed. A timing device receives the speed signal, determines the period of the most recent pulse of the speed signal, and responsively produces an instantaneous period signal that has a value representative of the determined period. A microprocessor receives the instantaneous period signal, determines an instantaneous speed value of the rotating wheel and an average speed value of the rotating wheel based on previous wheel rotations. The microprocessor further produces an instantaneous torsional velocity signal that has a value equal to the difference of the average speed value and the instantaneous speed value, and an instantaneous torsional displacement signal in response to numerically integrating the torsional velocity signal value. Finally, an output device receives the instantaneous torsional signals and displays the representative values.
Abstract:
The vibrator includes a columnar vibrating body consisting of a piezoelectric material. The vibrating body is formed into a polygonal or cylindrical column and, when necessary, a through hole is formed axially thereof. Furthermore, the vibrating body is polarized. On side faces of the vibrating body, at least three external electrodes are formed. Also, when the through hole is to be formed, an internal electrode is formed on its inner circumferential surface. By applying the driving signal to these electrodes, the vibrating body bends and vibrates. And, when the rotational angular velocity is applied to the vibrating body about its axis, a coriolis force is produced responsive thereto. By this coriolis force, the vibrating direction of the vibrating body changes, and a voltage is produced between the two external electrodes. By measuring the voltage, the rotational angular velocity applied to the vibrator can be measured.
Abstract:
Apparatus and method for detecting torsional vibrations of the shaft of an exciter of a turbine-generator, according to which a permanent magnet generator is connected to be driven by the exciter shaft and has an electrical output for providing an output voltage having a frequency proportional to the rate of rotation of the exciter shaft; and the electrical output is connected to signal processing circuitry serving to derive a signal representative of torsional vibrations experienced by the exciter shaft.
Abstract:
A piezoelectric rotary actuator including: a rotatable member; a spiral member fixed at its inner end to the rotatable member; one or more piezoelectric layers attached on one or both sides of the spiral member; means for rotatably supporting the rotatable member relative to the outer portion of the spiral member; and an electrode for applying a voltage across the piezoelectric layer or layers, to bend the spiral and rotate the rotatable member.
Abstract:
A torsional acoustic wave generator for use in an acoustic drill-string telemetry system, the generator having a reaction mass rotatably mounted near the lower end of a drill string, and a fluid coupling for generating a torque between the reaction mass and the drill string and thereby applying a sudden torsional pulse to the drill string. In the disclosed embodiment of the invention, the fluid coupling comprises a number of chambers rigidly connected to the reaction mass, an equal number of vanes rigidly connected to the drill string and disposed in the cylinders, and a mud control valve for selectively directing drilling mud into the chambers to generate a torque between the chambers and the vanes, and thereby apply to the drill string a torsional pulse that is independent of such factors as drill-string angular velocity.
Abstract:
The present invention is a torsional vibration monitoring method and an apparatus for performing the same, in which torsional vibrations produced in a rotating shaft system for use in such as a turbine generator are measured at a small number of certain positions therealong at which the measurements are possible, the torsional vibrations are linearly decomposed and torsional vibrations at arbitrary positions on the rotating shaft system are estimated from the linear decompositions.