Showing papers on "Rotational speed published in 1975"

Velocity Gradient Calibration of Jar-Test Equipment

Abstract: The jar-test procedure is widely used to simulate the water-pretreatment process in the laboratory to produce data for process control, yet few carefully controlled jar-test techniques are found in related literature. Jar-testing has depended upon the approach of each investigator.1 3 However, the interpretation of jar-test data must be founded on unvarying and well-calibrated techniques if they are to be quantitatively meaningful. One of the important variables in the procedure is the mixing intensity, which is related to the rotational speed and the configuration of the agitator as well as the geometry of the mixing vessel. The purpose of this study was to determine the mixing intensity, expressed as the mean velocity gradient "<7," throughout the applicable speed range, using various jar-test configurations. The resulting data should prove useful for application of laboratory data to water-treatment-plant design. Camp1 has called attention to the facts that (1) the fluid condition in full-scale plant mixing and flocculation basins is always turbulent, even when G values are relatively low; and (2) at speeds commonly used in jar-test machines, laminar flow conditions may occur. One object of this study was to evaluate the minimum threshold speeds above which turbulence always occurs in jar-testing. Camp and Stein5 applied Stokes' theory6 to relate the total energy input to what they called a root-mean-square velocity gradient G (Stokes' theory states that the velocity gradient equals the square root of energy dissipation at a point, divided by the absolute viscosity of the fluid): G= du = [W~ dz V fl (1)

Method for trueing commutators and slip rings

Abstract: Trueing of commutators and slip rings of large industrial motors, generators, convertors and the like without dragover of copper into insulating spaces between commutator segments or loading of surface of the trueing tool is afforded by employing an ultra-high speed grinding wheel mounted on the shaft of a precision portable electric motor mounted for traversing across the width of the contact surface. A grinding wheel in a grit range of 150 to 180 is operated at a peripheral surface speed at the grinding point of at least 7,000 feet per minute (2100 meters per minute). This speed corresponds to a 4,500 rpm rotational speed for a 6-inch. (0.1524 meter) diameter wheel. The motor and wheel are of a size and weight enabling manual mounting on a traversing compound adjacent the surface to be ground.

Two-way control circuitry for rolling mills - has time base circuit and tachometer measurement of rotational moment changes

Abstract: An electronic circuit for two-way measurement and control of the drive speed of consecutive roll installations of a continuous rolling strand completes the change in rotational movement of rolling stand rolls and adjusts the rotational speed accordingly as the material being rolled passes through. Sensors give a time based impulse to the circuitry as the rolled material passes them and this is combined with values from tachometers registering the rotation of D.C. drive motors. The rest of the circuitry is then combined of components to adjust the roll speed to compensate for alterations in turning movement due to the passage of the rolled material.

A histologic assessment of low-torque, ultrahigh-speed cutting technique.

Abstract: lh 11 e pu pa response to rotary cutting instruments is influenced by several factors: speed of the cutting instrument, type and size of the cutting instrument (bur or diamond), torque capability of the driving instrument, technique employed by the dentist, cooling armamentarium, and proximity to the pulp. At ultrahigh speeds, with the low-torque air turbines available, studies of rotational speed and torque indicated parameters of cutting speeds for most efficient removal of tooth structure with minimal frictional trauma.‘-” Excessive cutting pressure causes stalling, with large bites and inefficient frequency; while the reverse (low pressure) allows high rotational speed and minimal bite. Varying the bur or diamond size, bur design, and bur sharpness at compared torques can produce different cutting efficiencies with resultant varying frictional response.ls li, ; In other studies, torque capabilities of the turbines and the technique employed by the dentist were again related to cutting efficiency and frictional and vibratory responses resulting in varying pulpal responsesy-” It has been found that optimum operating technique, at ultrahigh speeds with low torque, allows efficient removal of tooth structure with short periods of instrument-tooth contact and less friction, in contrast to a technique utilizing high torque at ultrahigh and low speeds.“-I’; It has been documented that excessive heat can be transmitted to the dental pulp with resultant significant cellular damage.“-‘7 Maintenance of almost normal intrapulpal temperature can be accomplished by water or water-air spray or air and the aforementioned factors; however, the question of desiccation resulting from use of air as a coolant has not been resolved.“S-“a The clinical advantages and success of a flexible cooling armamentarium have been reported.l”, ‘(is 35 The action of any coolant at ultrahigh rotational speeds is one of cooling the entire coronal portion of the tooth.“’ Photographing at a rate of 250,000 frames per second, wherein a rotating bur and the spray can be observed in a portion of a

Phase control system for rotary means

Abstract: A phase control system for a rotary member is provided which has a device for adjusting the rotation of a rotary member so as to make the rotational speed and rotary phase of the rotary member coincident for a reference frequency signal. The phase control system has a rotational speed control function to lock the rotary phase of the rotary member at the reference frequency signal without especially providing a device which makes the rotational speed of the rotary member coincident with the reference frequency signal.

Drive arrangement for the auxiliary aggregates of a motor vehicle

Abstract: A drive arrangement for the auxiliary aggregates of a motor vehicle equipped with an internal combustion engine which includes an electrical power supply system with a generator and a battery; only those auxiliary aggregates which have a power requirement dependent on the rotational speeds are thereby driven from the internal combustion engine as heretofore whereas all auxiliary aggregates which have a power requirement independent of the rotational speed are driven in common from an electrical motor operating at substantially constant rotational speed and fed from the electrical power supply system; a thermionic converter operable by means of the fuel of the motor vehicle is thereby provided as generator.

Method and apparatus for winding yarn onto a cross-and-cone wound bobbin

Abstract: A method for winding yarn on a cross-and-cone wound bobbin, the yarn beinged at a constant speed from a spinning frame or from a texturing machine and temporarily held in a receptacle and then wound on the bobbin at a variable and controlled speed. The speed of winding is controlled by changing the position of the point of contact between the bobbin and a drive element, or by periodic breaking of contact between the bobbin and the drive element, the drive element rotating at a higher speed than the speed at which the yarn is fed, or by changing the rotational speed of the drive element in accordance with the deviations from the value of required filling of the receptacle with yarn. The apparatus includes a vacuum receptacle for the yarn equipped with a measuring sensor, a controller of the bobbin position including a pneumatic power device and a slider in which a holder of a cone element is rotably mounted, the controller being mounted on an arm and being connected with a piston rod of a power device. An analog system connects the measuring sensor with the power device.

Rheological Applications of a Drop Elongation Experiment

Abstract: A new method for determining the extensional flow properties of polymer solutions and melts is proposed and analyzed. The physical principle behind the method is that when a fluid drop is placed in a rotating field of a higher density fluid it will experience axisymmetrical extension or contraction when the rotational speed is varied with time. Under rather general conditions, an analysis is possible of the dynamic response of the drop in terms of measurable and controllable variables. This gives rise to a number of different steady and transient extensional flow experiments. Such experiments are described, and a specific unsteady experiment is used to verify the assumptions of the analysis and to indicate the quantitative accuracy of the method.

Hydro-mechanical transmission

Abstract: In a hydro-mechanical transmission for automobiles which has an input shaft, an output shaft, a differential gear set including an input element connected to the input shaft and an output element connected to the output shaft and two reaction elements, a first positive displacement hydraulic pump-motor connected to the input shaft, a second hydraulic pump-motor connected to the first hydraulic pump-motor through a pair of conduits, a first clutch for performing the low operational mode of the low speed ratio by connecting the second hydraulic pump-motor to one of the two reaction elements, and a second clutch for performing the high operational mode of the high speed ratio by connecting the second hydraulic pump-motor to the other reaction element, the operational modes being switched over when the rotational speed of the first clutch corresponds to or is synchronized with that of the second clutch, the improvement being, whether a setting signal is generated for increasing or decreasing the speed ratio, the signal is detected simultaneously with the correspondence of the rotational speed of each clutch, and upon correspondence thereof, the clutches are operated so as to perform the high operational mode when the setting signal is for increasing the speed ratio and to perform the low operational mode when the setting signal is for decreasing the speed ratio.

Magnetic recording and reproducing system with tape-to-head speed control

Abstract: Apparatus is provided for controlling the phase and speed of a motor for driving the rotary magnetic heads of a video tape recorder. An output of a signal generator, for example, a sawtooth wave, having a frequency corresponding to the rotational speed of the motor is compared with an external reference signal, for example, a 60 Hertz power line signal. A difference in frequency generates a varying error voltage whose polarity is indicative of the error direction. Relatively large or prolonged frequency errors result in an error voltage waveform having an abrupt and relatively large change. This error voltage is differentiated to create relatively large pulses of polarity depending on the direction of the error voltage. The relatively large pulses either charge or discharge a capacitor, the output of which changes the current to the motor so as to reduce the relatively large frequency error to a range suitable for handling by a conventional combined position and velocity servo system.

Apparatus for maintaining a constant surface speed of a rotating work piece being cut by a moving cutting tool

Abstract: An apparatus for maintaining a constant surface speed of a rotating work piece being cut by a moving cutting tool, comprising means for storing a first signal representing a binary coded decimal number which is further representative of the product of the desired constant surface speed of the work piece and a conversion constant. The apparatus is further comprised of a shift register for receiving a second signal representing a binary coded decimal number which is further representative of the current radial dimension of the work piece being cut, and means for storing a third signal representing a binary coded decimal number initially representative of an assumed rotational speed of the work piece. Means for arithmetically multiplying the binary coded number representative of the radial dimension of the work piece by the binary coded number representative of the assumed rotational speed of the work piece is also provided, along with a means for storing a fourth signal representing a binary coded decimal number which is further representative of the product of the radial dimension of the work piece and the rotational speed of the work piece. Further provided is a means for comparing the first signal representing the binary coded decimal number which is representative of the product of the desired constant speed of the work piece and the conversion constant with the fourth signal representing the binary coded decimal number which is representative of the product of the radial dimension of the work piece and the assumed rotational speed of the work piece, and for providing a fifth signal to adjust the binary coded decimal number representative of the assumed rotational speed of the work piece until the compared first and fourth signals are made approximately equal, at which time a sixth signal representing a final binary coded decimal number representative of the required rotational speed of the work piece is generated to control the speed of a motor that drives a spindle which holds the work piece.

Variable rate rotary pulse generator

Abstract: A counter circuit is incremented and decremented at a rate having a non-linear dependence on the rotational speed and direction of a rotary pulse generator.

Grinding method and apparatus

Abstract: A method of feed grinding workpieces comprises moving a workpiece into pressure contact with a grinding wheel and rotationally driving the grinding wheel relative to the workpiece at a predetermined speed of rotation different than the resonant frequency of the grinding wheel spindle assembly to effect feed grinding of the workpiece. Completion of the feed grinding or spark-out is detected after which the rotational speed of the grinding wheel is lowered to another predetermined speed different than the resonant frequency of the grinding wheel spindle assembly when operating in the spark-out mode. The high speed rotation during feed grinding assures good grinding quality and the low speed rotation during spark-out assures good surface finishing. By rotating the grinding wheel spindle assembly at speeds other than its resonant frequencies, damage due to large vibrations of the assembly is avoided.

Motor speed control circuit

Abstract: A speed-controlling circuit for controlling the rotational speed of a D.C. electric motor in which the electric current is supplied to the D.C. motor through a switching circuit which is periodically open for a predetermined fixed time interval. The switching circuit is controlled by electrical pulses having a repetition rate which varies in dependence upon the rotational speed of the motor, whereby to periodically interrupt the supply of current to the motor. SP This is a continuation, of application

Modulatable friction clutch controlled by a centrifugal force and angular acceleration sensitive valve

Abstract: A hydraulic valve and control system for sensing rotational speed and change in the rotational speed of a rotating clutch member, which valve controls the amount of pressure fluid delivered to a hydraulically actuated clutch, and for consequently modulating or permitting slipping of the friction clutch so as to regulate the output speed thereof. Drastic coefficients of friction changes occur in friction type clutches of the type contemplated for use with the present invention, and the hydraulic control system of the present invention senses or anticipates the change in rotational speed and consequently, the change in coefficient of friction of the clutch, and additionally the present invention substantially eliminates all valve friction and bi-stability of prior art devices of this general character.

Vehicle skid control system including vehicle speed sensor

Abstract: A device for effectively controlling the braking system of a wheeled vehicle to eliminate a possibility of skidding comprising an electric computing module which is responsive to electric signals fed thereinto from a vehicle speed sensor mounted on an extra wheel which mechanically contacts the road surface, and a vehicle supporting wheel rotational speed sensor

Apparatus for high speed winding of coils

Abstract: A device for the manufacture of coils in which the winding wire is guided to a winding head via a winding drum having an eccentric wire guiding bore. The winding drum and the winding head rotate in opposite directions so as to achieve an effective winding speed greater than either rotational speed.

Method and apparatus for control of anti-skid vehicle braking system

Abstract: An electronic control for a wheel controlled by an anti-skid hydraulic braking system has an input that always corresponds to rotational speed of the wheel and issues a brake-releasing input to a hydraulic regulator when the rate of deceleration of the wheel under braking force is substantially equal to the rate at which the wheel would decelerate when its sliding on a high friction road surface attained the peak of the curve of sliding effect versus coefficient of friction. An input commanding reapplication of braking force is issued when rotational speed of the accelerating wheel is equal to the rotational speed the wheel would have attained if it had decelerated from the rotational speed it had when the last previous brake releasing input was issued, through the time since that input, at a rate corresponding to best attainable deceleration of the vehicle on a surface affording the worst possible braking conditions.

Jitter prevention system for video signal processing

Abstract: Video signals are transferred from a phonograph record or low speed magnetic tape and stored on a magnetic sheet disc rotating at low speed. The magnetic sheet disc is then rotated at high speed to output the video signals to a television display or the like. In the invention, clock signals representing equal intervals of time are provided with the video signals on the phonograph record or low speed magnetic tape. The signals are picked up when the record or tape is rotated and the frequency thereof is analogous to the instantaneous rotational speed of the record or tape drive motor. The video is stored on the magnetic sheet disc by a write head. The magnetic sheet disc is provided withreference marks which are sensed when the magnetic sheet disc is rotated and the frequency thereof is analogous to the instantaneous rotational speed of the disc relative to the write head. The two frequencies are compared. The speed of the disc relative to the write head is controlled by varying the speed of the disc and/or rotating the write head relative to the disc so that the ratio of the instantaneous speed of the record or low speed tape to the design speed thereof is equal to the ratio of the instantaneous speed of the disc relative to the write head to the design speed of the disc. The video signals are thereby stored on the disc in the correct positions to eliminate jitter on the television display.

Control system for controlling translational speed of carriage with respect to rotational speed of mandrel

Abstract: A reciprocable carriage carries means for dispensing hardenable liquid resin and reinforcing glass fiber material on a rotatable mandrel to produce a tank wall. The control system includes means for maintaining the carriage speed constantly proportional to the mandrel speed to produce a cylindrical portion of a tank wall and means for continuously changing the carriage speed at a constant rate with respect to the mandrel speed to produce a conical portion of a tank wall.

Vehicle wheel rotational speed indicator - is for antilocking brake system and has Eddy current disc instead of aperture disc

Abstract: An eddy current disc rotates synchronously with or proportionally to the wheel and a U-shaped permanent magnet embraces the edge of the disc. THe magnet is fixed to one end of a strain gauge whose other end is anchored in the vehicle frame. The force resulting from the eddy currents in the disc deflects the magnet tangentially to the disc and the rotational speed is determined by measuring the resistance of two meander-shaped coils in the strain gauge in a bridge circuit. The eddy current disc is pref. a brake disc having good electrical conductivity.

Method of correcting rotational speed of screw propeller

Abstract: The rotational speed of a screw propeller mounted on a propeller shaft of a ship is correctively increased or decreased by locally heating the back or face side of each blade of the propeller along a plurality of paths substantially parallel to and inward from the trailing edge of the blade in a region from a radial position about of 0.5 R to the blade tip, where R is the tip radius, particularly from 0.6 to 0.7 R, and cooling the parts thus locally heated thereby to form wash-back in each blade between the trailing edge and the heating paths thereof as a result of angular deformation accompanying plastic deformation due to the heating and cooling and thereby to decrease or increase the effective pitch of the propeller.

An Optical Technique for Measuring the Velocity of a Fluid

Abstract: The technique described is based on a refraction phenomenon. Objects observed through a rotating transparent parallel-faced prism have images which move relative to the object. When the objects are small tracer particles suspended in a moving fluid, the velocity of the fluid can be measured by varying the rotational speed of the prism until the component of the image velocity normal to the prism axis is cancelled. The point in space at which the measurement is made is fixed by the intersection of the line of sight of the viewing telescope with a thin transverse beam of light used for illuminating the tracer particles.

Ignition timing control unti

Abstract: PURPOSE: By performing the angle of lead owing to the admission pressure by using a mechanical vacuum angle of lead device and the angle of lead owing to the rotational speed electrically, the complicated angle of lead characteristic with a broad control range shall be able to be realized. COPYRIGHT: (C)1977,JPO&Japio

Device for testing the ability of a person to recognize synchronous speeds

Abstract: The equipment is to test psychologically drivers of all kinds of motor vehicles. With this equipment one can test the competence in evaluating speed, which is based on the psychophysiological attribute, that is, the ability of perceiving motion. Inside the casing, are located the electric system of the equipment and the driving mechanisms of the two disks. The left disk rotates with a constant rotational speed and has three constant rates of rotational speed. The right disk has three rates of variable speed, regulated automatically within certain limits by the tested person. The test consists in the tested person trying to regulate the rotation speed of the right disk in order to obtain the same rotation speed as on the left disk, within a specified period of time. The result of the test consists in measuring the differences in rotation speeds of both disks, as recorded automatically on the scale of the tachograph.

The Continuous Aluminum-Foil Hydrometeor Sampler; Design, Operation, Data Analysis Procedures, and Operating Instructions.

Abstract: : The continuous aluminum-foil hydrometeor sampler is an airborne meteorological instrument that uses a continuous ribbon of aluminum-foil which moves at a constant speed past a 14.51 sq cm sampling area aperture exposing the foil to the ambient air-flow inflight. The aluminum-foil is backed by a rotating drum for exposing the foil immediately behind the aperture as well as for metering the amount of foil exposed in relation to the drum's rotational speed. This drum is finely grooved to enhance the imprint of the impacting hydrometeors. Both liquid drops = or > 100 micrometers and solid particles = or > 50 micrometers can be identified, measured, and counted. The frozen particles, depending upon orientation, impact on the foil leaving an almost exact replica. However, the imprint size of liquid drops can be up to 30 percent greater when sampled on a C-130 aircraft, depending on the true air speed of the sampling. Knowing the true aircraft speed, the foil advance speed, aperture width, and the ratio of imprint to true size, the hydrometeor size distribution and mass concentration can be determined along the aircraft's sampling path.

Encapsulated Tuned Dampers for Jet Engine Component Vibration Control

Abstract: = breadth of beam = Young's modulus = real part of complex Young's modulus of damping material = effective (complex/real) flexural rigidity of beam = Young's modulus of metal outer layer/viscoelastic core = resonant frequency in nth mode (Hz) = factor by which centrifugal loading exceeds unit gravity = thickness of wall = second moment of area of viscoelastic core/metal outer layer about neutral axis = length of beam = time dependent load per unit length = time = axial coordinate along beam, with root as origin = transverse displacement of point on beam = nondimensional parameter = loss factor of composite beam /damping material ** = first eigenvalue of cantilever beam ( ~ 12.36) = effective mass per unit length of composite beam = density of damping material/metal outer layers = resonant frequency at zero rotational speed = resonant frequency (rad/sec)

Rotational speed checker

Abstract: PURPOSE: A detector support is rotatably installed to the rotary disc fixing part of a rotating body, whereby the relative position of both is maintained even if the rotating body is exchanged and the need for readjustment is eliminated. COPYRIGHT: (C)1977,JPO&Japio