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Showing papers on "Rotational speed published in 1993"


Journal ArticleDOI
TL;DR: In this article, a simple axisymmetric two-dimensional supersonic solution of a rotating radiation-driven stellar wind from the Friend & Abbott one-dimensional model of the equatorial flow is presented.
Abstract: We present a simple approximation that permits us to obtain the axisymmetric two-dimensional supersonic solution of a rotating radiation-driven stellar wind from the Friend & Abbott one-dimensional model of the equatorial flow. Our solution predicts the formation of a dense equatorial disk if the rotation rate of the star is above a threshold value, which depends on the ratio of the terminal speed of the wind to the escape speed of the star. Along the upper main sequence (earlier than B2), both the observed and theoretical values for this ratio decrease monotonically toward later spectral types. For early O stars, the disk can only form if the rotation speed is in excess of 90% of the critical (breakup) speed

328 citations


Journal ArticleDOI
TL;DR: In this article, a finite difference method is presented for simulating the combined heat and mass transfer processes that occur in a solid desiccant dehumidifier, which is the main component of the desitcant-based cooling system.
Abstract: A new finite-difference method is presented for simulating the combined heat and mass transfer processes that occur in a solid desiccant dehumidifier, which is the main component of a solid desiccant dehumidification and cooling system. The numerical method is of high-order accuracy, is numerically implicit, and is unconditionally stable. This method allows for more rapid simulation of the performance of desitcant-based dehumidification and cooling systems. Using the numerical method, the effect of the rotational speed on the performance of an adiabatic rotary dehumidifier was parametricaily studied, and the optimal rotational speed was determined by examining the outlet adsorption-side humidity profiles and the humidity wave fronts inside the desiccant dehumidifier.

124 citations


Patent
02 Apr 1993
TL;DR: In this article, an analytical rotor which holds a fluid in a chamber, typically to allow mixing with a reagent, and transfers the fluid to a receiving chamber in the rotor is described.
Abstract: The present invention provides an analytical rotor which holds a fluid in a chamber, typically to allow mixing with a reagent, and transfers the fluid to a receiving chamber in the rotor. The rotor comprises a holding chamber having an single exit duct and a receiving chamber connected to the holding chamber through the exit duct. The exit duct prevents flow at a first rotational speed and allows flow at a second, higher rotational speed. The exit duct may include a capillary passage in which capillary forces prevent flow until the rotational speed is increased. Alternatively, the exit duct may include a siphon.

103 citations


Journal ArticleDOI
Y. Chen1, H.B. Zhao1, Z.P. Shen1, I. Grieger1, B.-H. Kröplin1 
TL;DR: In this paper, a nine nodes curvilinear superparametric finite element is used to solve the problems of vibrations of high speed rotating shells of revolution, with consideration of Coriolis accelerations and large deformations.

102 citations


Patent
Kaoru Sawase1
15 Jun 1993
TL;DR: In this article, a multi-plate clutch mechanism is interposed between the hollow axle and a differential case, and drive torque is fed from one of the differential case and the other member rotating at a higher speed.
Abstract: Between an input shaft and each of left-wheel and right-wheel axles, a speed change mechanism and a multi-plate clutch mechanism are interposed so that a rotational speed of the axle is changed (for example, increased) by a speed change mechanism and is transmitted to a hollow axle. The multi-plate clutch mechanism is interposed between the hollow axle and a differential case. By coupling the multi-plate clutch mechanism, drive torque is fed from one of the differential case and the hollow axle, said one member rotating at a higher speed, to the other member rotating at a lower speed. When the ratio α of a rotational speed of the left wheel to that of the right wheel becomes greater than the predetermined value α0 and transfer of torque in a desired direction is no longer feasible. The multi-plate clutch mechanisms are hence made free. The multi-plate clutch mechanisms are controlled by a control unit.

76 citations


Journal ArticleDOI
TL;DR: In this article, a new example of thermal swing adsorption using a honeycomb rotor with a thin sheet of silica gel as adsorbent has been developed for dehumidification of air.
Abstract: A new example of thermal swing adsorption using a honeycomb rotor with a thin sheet of silica gel as adsorbent has been developed for dehumidification of air. Owing to improvement in the dynamic adsorption capacity and rapid thermal response of the rotor, the product humidity was reduced to 10-20% of the feed at an air velocity of 1-2 m/s through a 0.2 m-long honeycomb. The existence of an optimal rotation speed of rotor has been observed. It increased in proportion to a single term of velocity of regeneration air, divided by width of the rotor and bulk density of the rotor; the effects of temperature and humidity of the feed and regeneration air were small. A dimensionless formula for the optimal rotation speed was derived on an empirical basis

72 citations


Patent
Kaoru Sawase1, Takahisa Niwa1
15 Jun 1993
TL;DR: In this paper, a speed increasing/decreasing mechanism is interposed between a left-wheel axle (2) and a right wheel axle (3) to increase a rotational speed of the left wheel axle and then output the thus-increased speed to a first intermediate axle (14).
Abstract: A speed increasing/decreasing mechanism (6) is interposed between a left-wheel axle (2) and a right-wheel axle (3). The mechanism (6) is constructed integrally of a speed increasing mechanism (6A) and a speed decreasing mechanism (6B). The speed increasing mechanism (6A) is adapted to increase a rotational speed of the left-wheel axle (2) and then to output the thus-increased rotational speed to a first intermediate axle (14). The speed decreasing mechanism (6B), on the other hand, is adapted to decrease a rotational speed of the left-wheel axle (2) and then to output the thus-decreased rotational speed to a second intermediate axle (15). A first coupling (7) of the variable transmitted torque capacity type is interposed between the first intermediate axle (14) and the right-wheel axle (3) to transmit drive torque therebetween. A second coupling (8) of the variable transmitted torque capacity type is interposed between the second intermediate axle (15) and the right-wheel axle (3) to transmit drive torque therebetween.

60 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe aerodynamically excited supercritical disk vibration observed in experiments and show that at pre-flutter speeds, the fluid acts as a random excitation source, but at higher speeds the fluid and the disk are strongly coupled.

55 citations


Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the validity of the standard models of this boundary condition: vanishing radial stress, vanishing radial displacement, or finite stress at the center of an integral disk and collar assembly.

55 citations


Journal ArticleDOI
TL;DR: In this paper, the vapor flow in an axially rotating heat pipe has been numerically analyzed using a two-dimensional axisymmetric model in cylindrical coordinates and a parametric study was conducted for radial Reynolds numbers of 0.01, 4.0, and 20.0.

45 citations


Journal ArticleDOI
TL;DR: The two-phase flow pattern in a concentric annulus with a rotating inner cylinder has been investigated experimentally in this article, and the observed flow patterns were dispersed bubbly, ring-form, single-spiral, double spiral, triple spiral flows and transition regions.

Patent
29 Jan 1993
TL;DR: In this article, a rotational speed control of an electric motor of a hand tool with an actuating means for providing displacement in response to manual operation of the hand tool is described.
Abstract: The process of controlling rotational speed of an electric motor of an electric hand tool, including providing an electric motor of an electric hand tool with a rotational speed control comprised of displacement means for providing displacement in response to manual operation of the electric hand tool selected from the group consisting essentially of a linear displacement device for providing linear displacement (s) and an actuating dial for providing arcuate displacement (S); an elastic membrane to which the displacement means is articulatedly connected so that during displacement of the displacement means the elastic membrane deforms as a function of the displacement; actuating means comprising a sensor element coupled to the elastic membrane so that the sensor element produces an electrical output variable as a function of the deformation of the elastic membrane, the sensor element being selected from the group consisting essentially of a Hall sensor, an inductive sensor, and a sensor switch; and an electronic switch for rotational speed control connected to the actuating means, from which it receives the electrical output variable, and to the electric motor of the electric hand tool; and manually operating the displacement means of the rotational speed control to control the rotational speed of the electric motor.

Patent
Heinz Weiss1
22 Jan 1993
TL;DR: In this paper, a vehicle power distribution and control system for a motor vehicle with at least two driven axles is described. The control system includes a steering angle sensor, rotational speed sensors to monitor the rotational speeds of at least one axle and an electronic control unit.
Abstract: A vehicle power distribution and control system controls and distributes the power supplied to the wheels of a motor vehicle with at least two driven axles. One of the axles includes an axle differential gear. The control system includes a steering angle sensor, rotational speed sensors to monitor the rotational speeds of the wheels of at least one axle, and an electronic control unit. A differential lock for the axle differential gear is controlled by the control unit to equalize sliding effects that can occur between the wheels of one axle. The control unit calculates a theoretical rotational speed difference ratio from the value of the sensed steering angle for conditions of rolling without any slip and an actual rotational speed difference ratio from the sensed rotational speed values. The control unit compares the two rotational speed difference ratios with each other in predetermined time intervals and transmits control signals to the axle differential locks to increase the degree of locking of the axle differential lock when the actual rotational speed difference ratio is greater than the theoretical rotational speed difference ratio, and to reduce the degree of locking when the actual rotational speed difference ratio is smaller than the theoretical rotational speed difference ratio.

Patent
Hieda Tomoharu1, Ishizaki Sunao1
13 Dec 1993
TL;DR: A carriage motor control device that uses speed determination means (3) determining a set speed value to be set on the basis of an aimed angle value (SN13A) indicating an aimed rotation angle, an aimed speed value indicative of an estimated rotation speed and the rotation angle value, speed control means (4) for generating a speed control value to make the rotation speed value closer to the first speed value on a basis of a difference between the rotated angle value and the first rate value.
Abstract: A carriage motor control device that uses speed determination means (3) for determining a set speed value (SN12) to be set on the basis of an aimed angle value (SN13A) indicative of an aimed rotation angle, an aimed speed value (SN13B) indicative of an aimed rotation speed and the rotation angle value, speed control means (4) for generating a speed control value (SN7) for making the rotation speed value closer to the set speed value on the basis of a difference between the rotation speed value and the set speed value, angle control means (5) for generating an angle control value (SN8) for making the rotation angle value closer to the aimed angle value on the basis of a difference between the aimed angle value and the rotation angle value, selection means (8) for selecting the speed control value as a motor drive control value when the rotation speed value is larger than a first speed value and selecting the angle control value as the motor drive control value when the rotation speed value is smaller than the first speed value and, drive pulse generation means (6) for generating a motor drive signal modulated according to a magnitude of the motor drive control value and for outputting the motor drive pulse signal as a forward motor drive signal or a reverse motor drive signal on the basis of the signal indicative of the direction of rotation.

Journal ArticleDOI
TL;DR: An integrated approach toward the modeling of flexible spindles with angular contact ball bearings from basic principles is presented, which includes both the longitudinal and transverse vibrations of the shaft interacting with the nonlinear bearings.
Abstract: Experimental evidence (Shin, 1992) has shown that the natural frequencies of high-speed spindles with angular contact ball bearings decrease with increasing rotational speed. A recent study (Wang et al., 1991) illustrated that this phenomenon is caused by stiffness change of the bearings. A simplified approximation was used in the past analysis to examine the bearing radial stiffness at high speeds. While the investigation explained the experimental observations in a qualitative sense, the analytical results so far are not sufficient to quantitatively describe the spindle behavior under high speed and load operations due to the assumptions and approximations made in the modeling process. This paper presents an integrated approach toward the modeling of flexible spindles with angular contact ball bearings from basic principles. The local dynamics of the bearings are coupled with the global shaft motion. The model derived includes both the longitudinal and transverse vibrations of the shaft interacting with the nonlinear bearings. The influences of shaft speed on the bearing stiffness matrix and the system frequencies are studied. It is shown that the spindle dynamic behavior can vary substantially as speed increases due to the bearing gyroscopic moment and centrifugal force. These effects have been ignored in most of the previous spindle models. This unique characteristic, which is critical to high-speed machinery, is rigorously studied for the first time. Lab tests are conducted to validate the model. The analytical predictions are quantitatively verified by the experimental results.

Patent
26 Jan 1993
TL;DR: In this article, a pneumatic tire pressure determining system on a motor vehicle detects an actual rotational speed difference between rotational speeds of front or rear left and right road wheels of the motor vehicle, detects an operating condition of the vehicle, and calculates an adequate rotational Speed Difference (RSSD) between rotation speeds of the front or right road wheel based on the detected operating condition.
Abstract: A pneumatic tire pressure determining system on a motor vehicle detects an actual rotational speed difference between rotational speeds of front or rear left and right road wheels of the motor vehicle, detects an operating condition of the motor vehicle, and calculates an adequate rotational speed difference between rotational speeds of the front or rear left and right road wheels based on the detected operating condition of the motor vehicle. The system compares the adequate rotational speed difference and the actual rotational speed difference, and when the difference between the compared actual and adequate rotational speed differences exceeds a predetermined value, the system determines a pneumatic tire pressure reduction.

Journal ArticleDOI
TL;DR: An iterative method is developed to derive the system equilibrium configuration for given operating conditions and it is shown that significant errors will occur in predicting spindle characteristics and stability if the speed and load effects on the shaft/bearing dynamics are neglected.
Abstract: This paper presents an integrated study of a rotor/bearing structure, with specific interests toward high-speed spindle systems under rotating end loads. Considering the coupling between the rotating shaft and the nonlinear bearings, an iterative method is developed to derive the system equilibrium configuration for given operating conditions. With moving end loads, structural instability caused by high rotational speed is analyzed. The critical speeds and unstable speed regions are discussed. Machining chatter instability lobes are also derived using the spindle model. It is shown that significant errors will occur in predicting spindle characteristics and stability if the speed and load effects on the shaft/bearing dynamics are neglected.

Patent
07 Dec 1993
TL;DR: In this paper, the amplitude and phase of the HHC force is regulated by either manually or by active feedback control, to minimize any vibratory load transmitted to the airframe through the rotor blade drive shaft.
Abstract: Higher harmonic control (hereinafter HHC) of helicopter rotor blade vibrations is provided by an actively controlled, rotatable, slotted cylinder which is mounted at an outboard section of each blade. Continuous rotation of each cylinder about its longitudinal axis produces a periodic aerodynamic force on the blade at a frequency of twice the rotational frequency of the cylinder. The amplitude of force is controlled by the size of a slot opening in the cylinder while the rotational speed of the cylinder is synchronized to run at a multiple of the speed of a rotor blade drive shaft. The amplitude and phase of the HHC force is regulated, either manually or by active feedback control, to minimize any vibratory load transmitted to the airframe through the rotor blade drive shaft. A significant advantage offered by this concept relative to other HHC methods, such as high-frequency blade pitch motions actuated either by the swash plate or by moveable tabs at the blade trailing edge, is its low power requirement.

Patent
12 Aug 1993
TL;DR: In this paper, a speed change control method and apparatus for a vehicular automatic transmission having a first-speed clutch for establishing a first speed and a second-speed solenoid valve for supplying oil pressure to the secondspeed clutch to feedback control is presented.
Abstract: A speed change control method and apparatus for a vehicular automatic transmission having a first-speed clutch for establishing a first speed and a second-speed clutch for establishing a second speed, includes subjection of at least a duty ratio Dr of a second-speed solenoid valve for supplying oil pressure to the second-speed clutch to feedback control, so that the first-speed clutch is engaged while disengaging the second-speed clutch. This thereby increases a turbine rotational speed Nt toward the first-speed synchronous rotational speed. Further, an upper limit value Dmax of the duty ratio Dr is set, and the duty ratio Dr is subject to feedback control within a resultant duty ratio range, thereby preventing the duty ratio Dr from being set at an excessive value caused by a delay in the rise of the oil pressure. As a result, even if a depression of an accelerator pedal is suddenly increased during a downshifting process, an interlock problem can be prevented, thereby ensuring smooth speed change.

Patent
16 Nov 1993
TL;DR: In this paper, a misfiring detecting system for an internal combustion engine includes a first misfire determination unit for comparing an engine rotational speed variation amount computed by an engine RSPI computing unit, which computes a variation amount of the engine RPSI, with a misfire value set by a mis-fire determination value setting unit and determines the occurrence of mis-firing in the engine on the basis of a result of the comparison.
Abstract: A misfiring detecting system for an internal combustion engine includes a first misfire determination unit for comparing an engine rotational speed variation amount computed by an engine rotational speed variation amount computing unit, which computes a variation amount of the engine rotational speed, with a misfire determination value set by a misfire determination value setting unit and determines the occurrence of misfiring in the internal combustion engine on the basis of a result of the comparison, and a second misfire determination unit for determining the occurrence of misfiring in the internal combustion engine on the basis of: a result of comparison of a value indicative of a variation between engine rotational speed variation amounts computed by the engine rotational speed variation amount computing unit in the current and immediately preceding cycles, respectively, with a first set value; and a result of comparison of a value indicative of a variation of variation between engine rotational speed variation amounts computed by the engine rotational speed variation amount computing unit in the immediately preceding cycle and that of a two preceding cycle, respectively, with a second set value, so that misfiring can be accurately detected by preventing erroneous misfiring detection.

Book ChapterDOI
01 Jan 1993
TL;DR: A superconducting magnetic bearing (SMB) of bulk YBa2Cu3O7−x having strong pinning force was assembled and cooled in a field cooling state at 77K as mentioned in this paper.
Abstract: A superconducting magnetic bearing (SMB) of bulk YBa2Cu3O7−x having strong pinning force was assembled and cooled in a field cooling state at 77K. Two SMB units were equiped with a rotational system and supported a rotating shaft weighing 2.5Kg with no mechanical contact. The SMB has achieved a rotational speed exceeding 42,000rpm with a radial runnout of 8µm or less. The rotating performance at high speed has disclosed by an active control assist in radial direction during accelerations.

Patent
13 Apr 1993
TL;DR: In this paper, the rotational speed of a spindle motor is detected and corrected by a change amount calculation/storage device, and a proper feed speed is commanded from a feed speed control device.
Abstract: An numerical control (NC) device capable of machining a workpiece with high accuracy by accurately commanding a feed speed of a tool, even if a sudden change occurs in an actual speed of a spindle motor. If a rotational speed of a spindle changes, a change amount calculation/storage device calculates and stores a change amount on the basis of the rotational speed already detected. A rotational speed detected by a rotational speed detection device is corrected thereafter according to the change amount, and a proper feed speed is commanded from a feed speed control device. If thread cutting is carried out by employing the NC device, the tool feed speed is commanded in proportion to the actual speed of the spindle motor, and therefore, even though the rotational speed of the spindle motor is lowered at the moment the workpiece is started to be subjected to thread cutting by the tool, a move command signal with a proper tool feed speed is outputted.

Patent
30 Jul 1993
TL;DR: In this paper, the rotational speed of the polygon mirror is calculated based on the rotation information of the mirror and the phase information obtained about the mirror using a clock signal, which is then added to the scanning speed deviation to control the rotation speed.
Abstract: An image exposure apparatus for eliminating discrepancies between the positions in the main scanning direction desired to be exposed and actually exposed by a laser beam. This may be achieved by controlling the rotational speed of the polygon mirror based on accurate rotation information. A first and second beam detectors for detecting the scanning laser beam in the main scanning direction are positioned at either side of the region of a recording medium where an image is to be formed. These detectors output signals upon detecting the laser beam. The scanning speed in the main scanning direction is calculated based on these signals. Further, deviation in speed in the main scanning direction is obtained from these signals. Rotational speed and phase information obtained about the polygon mirror using a clock signal is added to scanning speed deviation to control rotational speed of the polygon mirror. The variation in rotation of the polygon mirror may be compensated for by modulating frequency of an image clock signal according to the variation in scanning speed of the laser beam. Discrepancies may also be eliminated by timing the image signals that modulate the laser beam to compensate for variations in the speed of the polygon mirror.

Patent
15 Apr 1993
TL;DR: In this paper, a lower-speed clutch for establishing a lower speed gear is engaged while a higher-speed cluttered gear is disengaged to increase the turbine rotational speed toward a synchronous rotation speed associated with the lower speed.
Abstract: During downshift operation of an automotive automatic transmission in which a lower-speed clutch for establishing a lower-speed gear is engaged while a higher-speed clutch, which has established a higher-speed gear, is disengaged, to increase the turbine rotational speed Nt toward a synchronous rotation speed Ntj associated with the lower-speed gear, speed change control is carried out according to the same control method regardless of whether the engine is in a power-on or power-off state. A target change rate (Nir)' of turbine rotational speed associated with the higher-speed clutch and a target change rate (Nia)' of turbine rotational speed associated with the lower-speed clutch are set, and a change rate (Nt)' of the turbine rotational speed is detected. The transmission torque through the higher-speed clutch is controlled in a feedback manner such that the detected change rate (Nt)' coincides with the change rate (Nir)', and also the transmission torque through the lower-speed clutch is feedback-controlled such that the change rate (Nt)' coincides with the change rate (Nia)', thereby carrying out downshift.

Patent
07 May 1993
TL;DR: In this paper, different duty controls at the time of change in rotating speed and stable rotating speed, respectively, are used to realize the driving of a brushless motor 3 which enables smooth and rapid change of a rotating speed coping with a load.
Abstract: By making different duty controls at the time of change in rotating speed and at the time of stable rotating speed, respectively, it is possible to realize the driving of a brushless motor 3 which enables smooth and rapid change of a rotating speed coping with a load.

Patent
20 Jul 1993
TL;DR: An abnormal vibration detecting device for detecting abnormal vibration of a rotational tub of a washing machine includes first and second abnormal vibration detectors as mentioned in this paper, which include a detecting lever rotatively moved where it collides with the tub when it vibrates transversely, and a detection switch responsive to the rotative movement of the detecting lever.
Abstract: An abnormal vibration detecting device for detecting abnormal vibration of a rotational tub of a washing machine includes first and second abnormal vibration detectors. The first abnormal vibration detector includes a detecting lever rotatively moved where it collides with the rotational tub when it vibrates transversely, and a detection switch responsive to the rotative movement of the detecting lever. The second abnormal vibration detector includes a rotational speed detecting section detecting the rotational speed of a motor driving the rotational tub and a comparator section comparing a speed signal detected by the rotational speed detecting section with a reference speed signal determined based on the rise characteristic of rotation of the rotational tub appearing in the state that the rotational tub is in the condition of slight abnormal vibration.

Journal ArticleDOI
TL;DR: In this paper, the vibration of a beam is studied with the configuration of the undeformed beam deviating from the radial direction at the clamped end, and the equation of motion is formulated based on the Hamilton's principle and then reduced to a matrix eigenvalue problem for constant rotational speed of the hub.
Abstract: The vibration of a beam is studied with the configuration of the undeformed beam deviating from the radial direction at the clamped end. The equation of motion is formulated based on the Hamilton's principle and then reduced to the form of a matrix eigenvalue problem for constant rotational speed of the hub

Journal ArticleDOI
P.S. Jones1
TL;DR: In this article, three commercially available liquid/liquid hydrocyclones (LLHC's) are evaluated in an operating oil field and the oil-removal capabilities of two static units and one dynamic or rotating unit are determined across a full range of operating conditions.
Abstract: Three commercially available liquid/liquid hydrocyclones (LLHC's) are evaluated in an operating oil field. The oil-removal capabilities of two static units and one dynamic or rotating unit are determined across a full range of operating conditions. Such variables as driving pressure, flow rate, reject rate, and rotational speed are investigated to optimize oil-removal efficiency. The key parameter of oil droplet-size distribution also is evaluated and its effects on performance are determined.

Patent
14 Jan 1993
TL;DR: In this article, a vibrator includes a vibrating table, a plurality of driven unbalanced shafts, arranged in pairs, and an adjustment device varies the vibrating frequencies and angular positions of the unbalanced bodies relative to one another.
Abstract: A vibrator includes a vibrating table; a plurality of driven unbalanced shafts disposed within the vibrating table and arranged in pairs; and a plurality of unbalanced bodies. A separate unbalanced body is connected to each unbalanced shaft. The unbalanced bodies can assume various vibrating frequencies and angular positions. An adjustment device varies the vibrating frequencies and angular positions of the unbalanced bodies relative to one another. Each shaft is driven by a separate motor; the motors are adapted to rotate in synchronism with one another at a predetermined rotational speed. The adjustment device includes an electronic controller for regulating each of the motors. The electronic controller includes an arrangement for changing the vibrating frequencies of the unbalanced bodies by briefly varying a rotational speed of the unbalanced shafts; and an arrangement for changing the angular positions of the unbalanced bodies relative to one another by briefly varying a rotational speed of at least one driven unbalanced shaft of a pair of driven unbalanced shafts.

Patent
26 May 1993
TL;DR: In this article, an electric shaver is provided with a motor to drive a cutter, a motor current sensing circuit, and a computation circuit which processes an output from the current sensing circuits.
Abstract: An electric shaver is provided with a motor to drive a cutter, a motor current sensing circuit, and a computation circuit which processes an output from the current sensing circuit. The computation circuit computes beard thickness, and a set range of motor rotational speed regulation according to beard thickness to lower rotational speeds for thin beards and to higher rotational speeds for thick beards, and thereby rotates the motor at optimum speeds according to beard thickness.