Abstract: In a rotating machine with employment of a sensor-less DC brushless motor, a terminal voltage of a motor is corrected in a phase corrector by using a motor phase current signal. At this time, the terminal voltage is processed in an integrator and a comparator so as to be converted into an ON/OFF signal having a duty ratio of 1:1. Then, a rotation signal is produced based on an induced voltage which is generated by rotating a permanent magnet rotor, so that a rotation sensor is no longer required. On the other hand, an output derived from the phase corrector is entered as a 1-pulse/1-rotation output signal into a PLL circuit. The PLL circuit contains a phase comparator, a low-pass filter, an oscillator, and a counter. The PLL circuit frequency-divides the 1-pulse/1-rotation output signal. The sine wave data are stored into a ROM with respect to each of the frequency-divided signal positions. The unbalance vibrations of the magnetic bearing are controlled every frequency-divided signal.

Abstract: A manufacturing method of a rotor for a permanent magnet-excited, high-speed electric rotary machine according to the present invention comprises, covering an outer circumferential surface of at least one permanent magnet by a fiber-reinforced plastic protection cover with prestress compressing in radial direction; inserting a steel sleeve into the at least one permanent magnet to form a permanent magnet assembly; preparing at least one permanent magnet assembly; inserting a rotor shaft into the steel sleeve while applying hydraulic pressure to an inner circumferential surface of the steel sleeve of the prepared at least one permanent magnet assembly to expand the steel sleeve; and then removing the hydraulic pressure to tight fit the at least one permanent magnet assembly onto the rotor shaft.

Abstract: A multi-stage compressor having at least two compressor stages comprises an inter-cooler provided between the stages for cooling a gas being discharged from a compressor in the preceding stage. The compressor stages are driven by a common electric motor, of which a rotating shaft is supported by magnetic bearings. A part of the gas cooled by the inter-cooler and a part of the work gas discharged from a bleed valve provided down-stream of a rear stage of the compressor are selectively introduced into the electric motor or the magnetic bearings. Thus, at the time of load operation the gas discharged from the inter-cooler is introduced into the motor or the magnetic bearings to cool them, and at the time of non-load operation the gas discharged from the bleed valve is introduced into the motor or the magnetic bearings to cool them. It is possible to ensure a flow rate of gas required for cooling the motor during non-load operation with economy during load operation.

Abstract: Active magnetic bearings supporting a rotor operated at high speeds is controlled by a controller. Tracking filters provided in the controller pick up forward vibration components in synchronism with the rotational speeds from the displacement signals of the rotor, and a mode separating circuit provided in a mode gain controller takes out displacements of the 3rd and 4th modes. Then, a gain controller provided in the mode gain controller determines suitable gains for the separated displacement signals. A mode synthesizing circuit provided in the mode gain controller synthesizes a controlled variable for each of the bearings from the control signals that are processed for the respective modes. By adding the control variable to the respective bearings, the vibration amplitude is suppressed in critical speed zones of high orders, and the rotor is stably operated up to a high-speed range.

Abstract: A magnetic bearing is provided with a simulating circuit for estimating a displacement of a rotor on the basis of a force which is exerted on the rotor. An output of the simulating circuit is compared with an actual displacement signal. A delay circuit and a subtracter are provided to subtract a run-out, which was estimated one period before the rotation of the rotor, from the displacement signal. A displacement signal from which the run-out component was eliminated is set to a new displacement signal. A signal which is obtained by adding an estimated run-out of one period before, namely, an output of the delay circuit to the run-out which was estimated by comparing the output of the simulating circuit with the new displacement signal is newly inputted to the delay circuit.

Abstract: A controller of magnetic bearing controls the rotor speed with a reduced drive current while suppressing the rotor vibration. The controller implements the ABS control, N-cross control, N-straight control and FF control in proper combination in addition to the basic PID control. A computer in the controller determines the activation of each control in accordance with a predetermined table of control plan in response to the detected rotor speed.

Abstract: A balancing method for balancing a flexible rotor is disclosed. First, the rotor is rotated and vibration of the rotor is measured to determine resonance speeds. Vibration exciting forces of frequencies synchronized with the rotor rotation in two orthogonal directions are imparted to the rotor or rotor support bearings while rotating the rotor at a speed near the respective resonance speeds. The amplitude and the phase of the vibration exciting force which reduces the resonance vibration of the rotor are then determined. A correction weight on the basis of the amplitude and the phase of the vibration exciting force is then determined. Balancing work on the rotor such as grinding of the rotor or addition of a mass to the rotor in accordance with the correction weight is then carried out, followed by a rotor rotation conducted for the purpose of confirming the effect of the balancing work.

Abstract: A control method and apparatus for suppressing the vibration components of a magnetic bearing. According to this invention, a vibration wave is sampled at pulses synchronized with the rotation of a rotor, the vibration waveform sampled values at each revolution are averaged, and only the frequency components synchronized with the rotation frequency of the rotor are extracted from the vibration waveform. In addition, the extracted components are subjected to Fourier transform, processed in a frequency region and subjected to Fourier reverse transform. The sequence of these signal processes produces a signal, and the vibration components are suppressed by this signal.

Abstract: A band pass filter multiplies an input waveform with first trigonometric functions at a plurality of frequencies and then filters the products. Furthermore, with that filtering step, the products are multiplied, or their phase is changed by a predetermined value, and the results are multiplied by the inverse of the trigonometric functions.The sum of this, for all frequencies, generated a filtered output waveform. Where the input waveform has two components, the corresponding outputs can be obtained from the read and imaginary components of the output waveform. In practice the trigonometric functions are produced by sine and cosine components at each frequency. In this way a band pass filter device is formed which is suitable for use in the control system of an apparatus which must be controlled continuously, such as a control system for a rotor.

Abstract: An adhesive composition for bonding fibers to a rubber is made of an aqueous dispersion composed mainly of a resorcinol/formaldehyde resin and a rubbery vinylpyridine copolymer latex. Particles of the rubbery vinylpyridine copolymer latex having a weight-average particle size of at least 0.15 micron, provided when the weight-average particle size is less than 0.16 micron, the particles having a particle size of at least 0.18 micron amount to at least 5% by weight.