639 results about "Rotational frequency" patented technology

A vertical axis windmill is provided wherein the amount of wind directed to blades in the power producing part of rotation and the mechanical load of multiple generators is controlled by a feedback control to maintain a relatively constant rotational frequency of the shaft of the windmill. In a preferred embodiment, two wind foils extend radially outwardly from the blades to thereby provide a scoop capable of pulling in more air than would normally be received by the blades. The wind foils then direct the wind flow to the power producing part of rotation of the blades for maximum power output, when necessary. The wind foils can close to control the wind flow to the blades. The generating capacity of a plurality of generators is also controlled in response to shaft rotation to maintain substantially constant shaft rotation.

In an apparatus for controlling a multi-cylinder internal combustion engine with partial cylinder switch-off mechanism which is switchable between an all-cylinder operation mode in which all cylinders are operated and a partial-cylinder operation mode in which operation of partial cylinders is suspended, the operation of intake valves and exhaust valves is suspended or resumed in a predetermined order with respect to all of the suspended cylinders irrespective of a rotational frequency of the engine. There are provided a solenoid valve on an intake side and a solenoid valve on an exhaust side for switching input hydraulic pressures for hydraulically operated switching devices respectively on the intake side and on the exhaust side between the driving state and the drive-free state. At the time of switching the operation, one of the solenoid valves on the intake side and the exhaust side is driven in advance. The subsequent number of rotations of a crankshaft is counted. When the number of this counting has reached a predetermined value, the solenoid valve on the other side is driven.

For measuring the rotational frequency of a movable game device, one resorts to an existing radio signal in the form of a broadcast signal or mobile communication signal within the framework of an open system, or to a radio signal of an evaluation unit within the framework of a closed system, so as to obtain, by means of an antenna having a directivity characteristic, a time-varying radio antenna receive signal which has a low-frequency modulation portion, the frequency of which corresponding to the rotational frequency of the movable game device.

The present invention discloses the present invention discloses a power toothbrush that includes a body portion 105. An elongated level arm 102 extends from one end of the body portion to a toothbrush head 101 disposed at a distal end of the toothbrush. The toothbrush head includes a plurality of brush bristles. The elongated lever arm 102 is mounted on a vibrating pivot 104 driven by rotational DC motor engaging and pushing a set of permanent magnets attached to a two-arm fork rotating along the lever arm 102. In a preferred embodiment, the DC motor drives a three-leg permanent magnets each disposed at a 120-degree phase from each other for driving the two-arm fork for generating a vibration that three-times the frequency of the DC motor's rotational frequency.

A rotating, transversely magnetized, magnet on a drill collar induces magnetization in a casing of a preexisting well. A coil rotating synchronously with the magnet produces a current at twice the frequency of rotation and having an amplitude that depends upon the distance from the magnet to the preexisting well. Alternatively, a variable magnetic field is produced in the casing using a switchable magnet. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

A vehicular active vibratory noise control apparatus includes an adaptive notch filter (second control signal generating unit) for generating a corrected error signal representative of a road noise only by removing the component of a rotational frequency (the component of an engine muffled sound) from an error signal, generates a first control signal from the corrected error signal and a reference signal, and reduces the component of the rotational frequency (engine muffled sound) at a position where a microphone is located (evaluating point).

In a method for ascertaining a rotational direction of a rotating body, one rotational direction and one rotational speed value which indicates the rotational frequency of the rotating body are ascertained in each of multiple measurements. The rotational speed values of the multiple measurements are compared to each other, and a rotational direction of the rotating body is ascertained from the measured rotational directions and the comparison of the rotational speed values.

In a motor-assisted hybrid vehicle, an active vibration control system suppresses torque fluctuations of an engine without detriment to the response of a static torque. An adaptive notch filter outputs a control signal depending on a harmonic basic signal generated by a basic signal generator from a rotational frequency of a crankshaft. A combiner combines the control signal with a drive signal for the generator motor and supplies the combined signal through a power controller to the generator motor. The basic signal is supplied to corrective filters having the transfer function of the generator motor to output a reference signal. The filter coefficient of an adaptive notch filter is successively updated so that an error signal representative of a rotational speed fluctuation of the crankshaft will be minimized.

PCT No. PCT/JP98/00739 Sec. 371 Date Oct. 28, 1998 Sec. 102(e) Date Oct. 28, 1998 PCT Filed Feb. 23, 1998 PCT Pub. No. WO98/38433 PCT Pub. Date Sep. 3, 1998Provided is a hydrodynamic gas bearing structure which can prevent occurrence of whirl not only in high-speed rotation but also in low-speed rotation, reduces such frequency that a floating rotational frequency in starting or stoppage of rotation increases, and is capable of shifting the floating rotational frequency to a low rotational frequency side. The hydrodynamic gas bearing structure comprises a shaft body (1) and a bearing body (2). A groove (11) is formed on the outer peripheral surface of the shaft body (1). The groove (11) consists of at least two concave parts, whose depths substantially differ from each other, which are formed serially in the circumferential direction, and has a circumferentially asymmetrical shape in a cross section perpendicular to the axis. The circumferential distance a between the intersection point (15) of a line (C) connecting the deepest point (14) of the groove (11) and the center (O) of the shaft body (1) and the outer peripheral line (Q) of the shaft body (1) and one edge (16) of the groove (11) positioned downward an air current (P) generated in rotation in relation to the intersection point (15) is larger than the circumferential distance b between the intersection point (15) and the other edge (17) of the groove (11) positioned upstream the air current (P) in relation to the intersection point (15). The ratio (d2/d1) of the mean depth d2 of a relatively shallow part of the groove (11) to the mean depth d1 of a relatively deep part of the groove (11) is less than 0.3. The hydrodynamic gas bearing structure is suitable for employment for a rotation driving part of a magnetic recording apparatus or a laser beam printer.

The invention discloses a friction wear testing machine and comprises an abrading agent slot, a grinding steel wheel that is suspended in the abrading agent slot, a boosting lever that has a vertical arm suspended between the grinding steel wheel and a lateral wall of the abrading agent slot, a servo sand slot that has a sand discharging mouth and a transmission pipe, a servo spring loading mechanism that is connected with a horizontal arm of the boosting lever, a load sensor that is serially connected between the servo spring loading mechanism and the boosting lever and a temperature sensor that is arranged on the back of a sample. A main shaft of the grinding steel wheel is arranged on a bearing holder, connected with a torque sensor through a flexible coupler and connected with a frequency-varied speed-regulating drive motor, and a computer adjusts and detects the sand discharge amount of the sand slot, the rotating speed and the torque of the frequency-varied speed-regulating drive motor, and the loading capacity of the servo spring loading mechanism in real time, and can detect and record the rotational frequency of the grinding steel wheel and sample temperature in real time. The friction wear testing machine can detect and analyze the abrasion resistance and the frictional behaviour of hard alloy products under the conditions close to real working conditions.

To provide a control circuit or the like of a brush-less motor capable of properly controlling current of motor windings by detecting positions of magnetic poles of a rotor at a rotational frequency of the rotor from low rotation which cannot lock a PLL circuit to steady-state rotation for rotating at high speed. Positions of magnetic poles are detected by a change in a magnetic flux (magnetic flux signal) of motor windings caused by rotating a rotor having the magnetic poles, thereby, a synchronizing signal (ROT signal) in synchronism with rotation of the rotor is generated. When the rotor is rotated at a low rotational frequency which cannot lock a PLL circuit, the rotor is driven by using predetermined two driving voltage vectors among outputable driving voltage vectors and when a rotational frequency capable of locking the PLL circuit is reached, the rotor is driven by successively outputting the outputable driving voltage vectors in synchronism with the positions of the magnetic poles detecting the outputable driving voltage vectors. Further, the magnetic flux signal is provided by using voltage between two phases at which phases and magnitudes of voltage drop caused by inductances of motor windings are equal to each other.

A variable frequency power system with a power source having a rotating output and a speed control to regulate rotational speed of the rotating output. A generator coupled to and driven by the rotating output of the power source, whereby the speed control of the power source directly controls output power frequency of the generator due to control of rotational frequency of the rotating output. A voltage regulator connected between the generator and the motor regulates output voltage from the generator to the electrical motor load. A system controller controls output power frequency of the generator. The system controller interfaces with the speed control of the power source and configured to monitor generator output and operational conditions of the electrical motor load. The system controller adjusts the speed control based on generator output and operational conditions of the electrical motor load.

A method of balancing a physical rotor includes: determining a first balance state of the physical rotor at one or more rotational frequencies; identifying one or more balance zones on a surface of the rotor; providing a computerised simulation of the rotor having the first balance state; providing a first test mass in a first test location within one of the balance zones on the rotor simulation; determining a second balance state of the rotor simulation; providing at least one subsequent test mass in at least one subsequent test location within a balance zone on the rotor simulation and determining at least one subsequent balance state of the rotor simulation; selecting a mass and location from one of the first and subsequent test masses and test locations; and performing a material deposition process to add the selected mass of material to the selected location on the physical rotor.

The invention discloses a torsional vibration error monitoring method for a shaft system of a steam turbine generator unit, a monitor and a system. The method includes the steps of S1, collecting output signals of rotation speed sensors, key phase sensors and bearing base vibration acceleration sensors on the steam turbine generator unit; S2, conducting Fourier transform on the collected output signal of each bearing base vibration acceleration sensor to obtain vibration spectrum signals; S3, extracting an amplitude value in the vibration spectrum signal of each bearing base vibration acceleration sensor under the corresponding rotation frequency; S4, obtaining the types of to-be-detected frequencies and separately extracting the corresponding amplitude value and phase under each type of to-be-detected frequency from the vibration spectrum signal of each bearing base vibration acceleration sensor to serve as feature parameters; S5, on the basis of a judgment principle and the extractedfeature parameters, judging whether or not torsional vibration errors of the shaft system occur in the steam turbine generator unit. By means of the method, real-time online monitoring of the torsional vibration errors of the shaft system is achieved.

A motor control apparatus provided with an inverter for successively commutating the current to a motor using a PWM signal; a PWM signal generating device for generating the PWM signal using a carrier signal; a rotational state quantity sensor for detecting a rotational state quantity; a phase difference detecting device for detecting the phase difference between the carrier signal and the rotational period based on the rotational state quantity; a frequency setting device for setting a frequency of the carrier signal to a value in accordance with a multiplier for one period in terms of electrical angle of the rotational period of the motor, when the rotational frequency is equal to or greater than a specified frequency and the phase difference is equal to or less than a specified value; and a synchronizing device for synchronizing a control period of the carrier signal to the rotational period.

A motor control method that includes the steps of: rotationally driving a motor that is provided with a rotor having permanent magnet pieces, and a stator; and short circuiting a plurality of phases of the motor when the rotational frequency of the motor is equal to or greater than a predetermined rotational frequency.

An apparatus for carry out a method of diagnosing abnormality of a reduction gear, the reduction gear including an intermediate shaft element disposed between an input shaft and an output shaft and rotating in proportion to a rotation of the input shaft to transmit the rotation to the output shaft, the apparatus has: a disturbance observer that obtains an estimated disturbance value regarding the reduction gear, based on a torque instruction and a velocity feedback-value acquired when a pair of driven members which rotate relative to each other with a motor as a driving source are in relative rotation at a constant velocity; a specific spectral component specifying portion for extracting a specific spectral component corresponding to a constant multiple of a rotational frequency of the intermediate shaft element from a frequency components of the estimated disturbance value obtained by frequency analysis; and a diagnosing portion, which compares an amplitude of the specific spectral component specified by the specific spectral component specifying portion with a threshold value, and diagnoses an abnormality in a case where the amplitude of the specific spectral component exceeds the threshold value, or a normality in a case where the amplitude of the specific spectral component is equal to or less than the threshold value.

A rotary fluid agitator is provided. The rotary fluid agitator essentially comprises a fluid conduit that is positioned vertically within a storage tank holding a quantity of fluid, such as a drilling fluid. At least one nozzle is attached to the fluid conduit for jetting a stream of fluid into to the fluid contained within the tank. A drive means is connected to the fluid conduit and rotates the conduit to sweep the nozzle through a 360-degree arcuate path at a predetermined rotational frequency. A fluid pump is attached in fluid communication with the interior volume of the tank and pumps a quantity of drilling fluid through a fluid circulation line and through the fluid conduit to be jetted out of the nozzle. As the nozzle is swept through the arcuate path a conically shaped fluid flow path is created in the fluid contained within the tank causing the jetted fluid to tangentially act upon the fluid thereby keeping all solid particulates mixed with the fluid in suspension.

A device for drilling and for removing material using a laser beam comprises: a rotating image rotator (2); a beam manipulator (1) which, when viewed in the beam direction, is arranged in front of the image rotator and which serves to adjust the angle and position of the beam relative to the rotation axis of the image rotator; and a focusing device (3) located on the output side of the image rotator. A compensating device (3, 13, 14, 15) is placed between the image rotator and the focusing device and rotates with the image rotator in the same direction of rotation and with the same rotational frequency. The compensating device has a parallel displacement unit (15) and an angle changing unit (13, 14), and the compensating device, in a basic setting, is adjustable in its rotating position relative to the image rotator.

A washing tub (11) is provided with a fluid balancer (20) having containing chambers (22) for containing fluid poured therein from the outside. A control section (30) controls the pouring of the fluid into the containing chambers (22) according to the output of a vibration detection section (41) for detecting the vibration of a receiving tube (13) and determines, according to the rotational frequency of a motor (12) and to the output of the vibration detection section (41), the rotational frequency of the motor (12) when the fluid is poured into the containing chambers (22). Thus, the fluid is poured into the containing chambers (22) according to the vibration and rotational frequency to reduce vibration caused by the eccentric distribution of laundry.

The rotors of a helicopter are powered by electric motors. The electrical energy required for this purpose is produced by a motor-generator unit, which comprises one or more internal combustion engines. The motor-generator unit can be secured under the cabin floor. This yields a hybrid helicopter that can set the rotational frequency of the rotors within a large interval.