Showing papers on "Rotational speed published in 1980"

Analysis of Rotating Stall in Vaneless Diffusers of Centrifugal Compressors

Abstract: Self-excited flow oscillations in radial vaneless diffusers of centrifugal compressors are investigated analytically using the linearized equations of motion for unsteady flows. Solutions of the differential equations are made to satisfy boundary conditions at diffuser inlet and exit which in typical conversion systems represent the coupling between the diffuser and upstream and downstream components. The results indicate that the rotational speed of the stall pattern is dependent on the diffuser radius ratio and the coupling conditions between the impeller and the diffuser. It is shown that the dependence of the onset of the flow oscillations on the diffuser radius ratio is strong if the conditions at diffuser inlet are such that low speed rotating stall patterns are generated in the diffuser. Onset of high speed rotating stall patterns is more affected by the coupling conditions between the impeller and the diffuser than by the diffuser radius ratio.Copyright © 1980 by ASME

Control device for controlling the rotational speed of a portable power tool

Abstract: A speed control device for portable power tools having particular applicability to electric drills. The speed control device is adapted to automatically adjust the speed of the motor in accordance with changes in the diameter of the tool bit used. The device includes a sensor that senses the opening and closing of the jaws of the chuck. The sensor is mechanically coupled to a potentiometer circuit whose output signal is varied in accordance with movement of the sensor. The output signal of the potentiometer circuit controls the firing angle of a thyristor 34, which in turn controls the current supplied to the motor. In addition, the preferred embodiment includes a speed select switch which is connected to the potentiometer circuit to set the appropriate speed range for the motor, given the particular type of work material.

Disc memory apparatus

Abstract: Data is selectively recorded on a plurality of circumferential, radially spaced on a rotating disc (32). Either the rotational speed of the disc (32) or a frequency of write clock pulses is varied so that the data density is substantially the same on all of the tracks.

Windmill transmission and control systems

Abstract: A wind-power plant in which the variable input speed of a variable wind turbine is converted to a substantially constant output speed of an electric generator comprises a speed holding system arranged between the output shaft (2) of the wind turbine (1) and the input shaft of the generator (26) This speed holding system includes at least one speed variator (20) connected to a signal processing device (25) The variator (20) is connected, via a variator shaft (21), to a first gear (22) of a planet gear arrangement The first gear (22) meshes with a second gear (13) which is fixedly connected to a gear ring (11) This gear ring (11) is fixedly connected to the output shaft (2) of the turbine (1), the arrangement being such that in the event of a change in wind speed, the rotational speed of the generator input shaft is maintained constant as the blade-pitch is changed in response to said change in wind speed

Engine rotation speed control system

Abstract: An engine rotation speed control system which comprises an actuator for prescribing the recovery position of a throttle valve, a recovery position sensor for detecting that the throttle valve is returned to the recovery position, an idle speed control unit for controlling the engine to a predetermined idling speed, and a negative pressure restricting unit for controlling the throttle actuator such that reduction in intake negative pressure to below a predetermined negative pressure is prevented. When the throttle valve returns to the recovery position with the engine speed in excess of an upper limit of the idling speed, the actuator is controlled by the negative pressure restricting unit. When the engine speed falls below the upper limit, the idle speed control unit is actuated. Upon engine starting, the actuator is set such that the opening degree of the throttle valve suitable for the engine starting is obtained before the starter starts operating.

Incremental rotary viscometer

Abstract: A rotary viscometer of the type which measures the viscous torque to which a rotating spindle is subjected, by measuring the current drawn by the electric motor driving the spindle. True viscosity, i.e. the slope of the torque-spindle rotation speed curve, is approximated by varying the spindle speed stepwise in sets of speed measurements having a fixed speed difference, and obtaining the difference between the corresponding torque values for each set. By repeating this process throughout the desired speed range, an approximate derivative of the torque-speed curve is obtained, corresponding to an approximation of the true viscosity of the fluid being characterized.

Method of controlling the speed of a drill, hammer-drill, or rotary hammer and apparatus therefor

Abstract: The invention is directed to a method of controlling the speed of an electronically controlled drill, hammer-drill or rotary hammer driven by an electrical motor wherein the rotational speed is first raised from zero to a predetermined start-drill speed and thereafter, from the start-drill speed up to the working speed. The rotational speed is held automatically at the start-drill speed for a predetermined time interval. The apparatus of the invention for carrying out the above method is an electronic control circuit connected to the motor for adjusting the start-drill speed and the working speed. The electronic control circuit includes a control unit (30) for interrupting the ascent of the, rotational speed for a predetermined interval when the start-drill speed is reached.

Electric motor control for vacuum cleaner

Abstract: Disclosed is an improvement in a vacuum cleaner having a roller-shaped brush mounted in the vacuum nozzle thereof. A separate rotational speed control is provided for the electric motor which operates the roller-shaped brush and in preferred embodiments this rotational speed control is adjustable by the operator of the vacuum cleaner. In a further embodiment, two separate rotational speed controls are provided, one controlling the speed of the roller-brush motor and the other controlling the speed of the vacuum-generating motor. A still further embodiment comprises a single rotational speed control which can be interchangeably switched into or out of connection with either the roller-brush motor or the vacuum-generating motor. A still further embodiment discloses a roller-brush motor speed control which can be added to existing vacuum cleaners.

Method and apparatus for controlling and regulating a motor with a permanent magnetic rotor

Abstract: A method and an apparatus for controlling and regulating an electrical motor, especially a reactive motor for time-keeping devices such as clocks. The motor has a permanent-magnetic rotor with at least two poles, and a stator with at least two coils. In a normal speed mode one of coils is supplied with driving pulses whereas the second coil senses the rotational speed of the rotor. If the rotational speed of the rotor falls below a predetermined value, a self-starting mode is initiated wherein the first and second coils are alternately supplied with driving pulses. In this self-starting mode the frequency of the pulses supplied to the first and second coils is increased until normal speed has been reached wherein the self-starting mode is switched off and the normal speed mode regulation is switched on.

Power delivery system having a pressure modulated hydrodynamic retarder for controlling a load

Abstract: A pressure modulated hydrodynamic retarder is provided for a power delivery system and speed sensing means is provided for sensing the rotational speed of the output of the retarder for producing a corresponding pressure fluid flow which acts to vary the fluid relief pressure of a pressure control valve for the retarder and consequently varies the torque of the retarder in accordance with its rotor speed. In this manner the retarder is modulated as determined by its output speed and when the invention is used in a hoisting operation, as the lowering speed increases due to the falling load the retarding action of the retarder also increases. A particularly desirable form of sensing means includes a variable flow fluid pump which is driven at a speed proportional to the lowering speed of the load to proportionately vary the retarding ability of the retarder. The retarder system may include a one-way clutch between the retarder rotor and the power output shaft to provide for free-wheeling of the retarder when the shaft is rotated to raise the load, and which one-way clutch connects the rotor to the shaft when the shaft is rotating in the opposite direction to lower the load and this arrangement permits raising of the load without interference from the retarder and then automatically connects the retarder to the shaft when the load is lowered.

Dispergieren im flüssigen Zweiphasensystem

Abstract: Dispersion in a liquid two-phase system. The principal parameter of interest in the reliable design of stirred reactors for systems of two immiscible liquids (extractors, polymerization reactors) is the interfacial area between the two liquids. However, a knowledge of further operating parameters, such as the minimum number of revolutions per unit time for complete dispersion, rotational speed for phase inversion, and the scale-up behaviour, is very important. Results published so far on these questions are surveyed.

Control method of engine rotation speed

Abstract: PURPOSE: To improve the capacity of response to changes in the control of rotation speed at the time of idling operation by correcting the ignition timing in the direction to restrain the lowering and the change of the rotation speed. CONSTITUTION: When warming up is sufficient and a throttle valve 16 is perfectly closed in an idling state, the average value N 1 of the rotation speed N within the newest crank angle 120° is read out, and the newest target rotation speed NF corresponding to the idling operation is read out. In accordance with the deviation ΔN, a correction amount of idling time lead angle θISC is obtained from a map. Meanwhile, a basic value of lead angle θBSE from a map using a suction amount signal Q/N i and N i for for its main functions and a correction amount of ignition lead angle θα corresponding to various engine parameters are obtained. These values are added for calculating a lead angle value θ= θBSE+θα+θISC, which is outputted to an output circuit 113. This construction permits to correspond to the change of the rotation speed at the time of idling with high capacity of response. COPYRIGHT: (C)1982,JPO&Japio

Method and apparatus for controlling rotation speed of engine

Abstract: A method and apparatus for controlling the rotation speed of an engine by the steps of calculating a desired value of the idling rotation speed of the engine, sensing the actual idling rotation speed of the engine, calculating the deviation of the sensed actual idling rotation speed from the desired value, calculating a data of a rotation speed control factor on the basis of the deviation, limiting the control factor to within a control range between an upper limit and a lower limit, storing a correction factor related to a value of the control factor used under a specific operating condition of the engine, calculating the upper limit and the lower limit of the control factor using the value of the correction factor, and controlling the amount of intake air or the amount of the air-fuel mixture supplied to the engine on the basis of the value of the control factor thus calculated.

Multi-speed fan assembly

Abstract: Apparatus for rotating a fluid impeller of a centrifugal or axial flow fan, at multiple speeds. A fan is provided with a first and a second electric motor for drivingly rotating a fluid impeller at relatively fast and slow speeds, respectively. The rotor of the first motor directly drives the fluid impeller; the second motor is connected to the impeller shaft of the fan through a belt drive, with pulleys sized to reduce the impeller's rotational speed relative to that of the second motor. Only one of the motors is provided with a start winding. Control means selectively energize the first and second motors, and are operative to energize the one motor long enough to bring the other motor up to operating speed.

Governing fuel injection and hydraulic transmission simultaneously

Abstract: A method of controlling an internal combustion engine (14) having a power control (15) and a variable hydrostatic transmission (16, 17) including a hydraulic pump (16) driven by the internal combustion engine, and a hydraulic engine (17) connected therewith. By automatic adjustment of the power control (15) and the ratio (E) of the hydrostatic transmission (16, 17) independently of each other according to a predetermined mathematical control function (FIG. 1) which describes a desired relationship between power and rotational speed of the internal combustion engine, a specific discrete power output is delivered between zero load and full load only at an associated discrete rotational speed of the internal combustion engine.

High speed precision planter

Abstract: In a vacuum planter a second disc with standard perforations is placed within the housing so that twice as many seed may be dropped with the same rotational speed and perforation spacing.

Apparatus for controlling rotational speed of internal combustion engine

Abstract: A feedback control system for controlling the rotational speed in idling operation of an internal combustion engine mounted on a vehicle by altering an intake air amount is combined with means for detecting a predetermined engine operating condition where the rotational speed of the engine is decreased or restrained by the vehicle speed and means for limiting a control signal manipulating an intake air amount under a predetermined upper limit in the case where the predetermined engine operating condition is detected so that the control system is prevented from excessively increasing an intake air amount. Preferably the operation of the limiting means as well as the operation of the feedback control is performed by a programmed microcomputer.

Apparatus for controlling the rotational speed of the spindles of a spinning preparatory machine

Abstract: The invention concerns an apparatus for controlling the rotational speed of the spindles of a spinning preparatory machine equipped with spindles and flyers. The proposed control arrangement comprises an infinitely variable variator, which is adapted or adjusted by using a control shaft which is rotatably indexed or stepped. The control or adjustment shaft is moved by a control motor which received its control or switching impulses from a motor control device comprising a programmable indicator or set value transmitter for the desired or set value and a correction element. According to a particularly advantageous design the correction element is of the form of a crossbar distributor arrangement. The apparatus is comfortable and easy to use by the operating personnel and permits, among other advantages, extremely accurate adaptation or adjustment of the spindle rotational speed. The adaption operations can be effected while the machine is running.

The Flow Characteristics of a Piston-Cylinder Assembly with an Off-Centre, Open Port

Abstract: Laser-Doppler anemometry has been used to measure the mean and r.m.s. values of the velocity components of the flow in a reciprocating assembly containing an off-centre, open port in the cylinder head and a flat piston. The port was inclined at an angle of 60° to the head and gave rise to a three-dimensional flow with no significant compression. The rotational speed was 200 rev/min, ensuring fully turbulent flow.The measurements were restricted to the axial and circumferential velocity components and were made on three radial planes in order to describe the flow in sufficient detail. The results are presented in the form of radial profiles and vector diagrams in both the axial and cross-stream planes. The main flow pattern on the intake stroke is of the same general shape as that previously obtained with a symmetric port, a large vortex occupying the space bounded by the indrawn jet with a much smaller vortex in the corner between the cylinder head and wall. These vortices are however no longer symmetrica...

Method and power transmission system for operating a road planar machine

Abstract: The method and power transmission system of this invention for driving a road planar machine has the cutter unit in a positive mechanical drive with the drive shaft of a machine power unit through a hydraulically actuated clutch mechanism. The wheel traction units for the machine are continuously driven from the power unit by hydraulic motors operated by variable volume displacement pumps. A control system for retaining the power unit at a set rotational speed required for a predetermined cutting or planing load is responsive to a drop in the set rotational speed, resulting from the cutting unit encountering an overload, to actuate the variable displacement pumps to decrease the forward speed of the machine without appreciably reducing the rotational inertia force of the cutting unit. If the cutting unit overload is of a short duration or momentary the set rotational speed of the power unit is resumed. If the overload, as observed by the machine operator after the occurrence of the drop in the set rotational speed of the power unit, appears to be severe or prolonged, the control system may be manually discontinued and the machine manually controlled until the cutting unit overload has been removed at which time the control system may again be placed into operation.

A high speed spinner for magic angle spinning NMR

Abstract: A high speed spinner for high resolution solid state NMR is described. The cylindrical rotor is supported by two air bearings which makes the orientation of the spinning axis independent of small imbalances and rotation speed. With compressed air speeds up to 7 kHz have been obtained with a phi =10 mm rotor.

Control device of diesel engine

Abstract: PURPOSE: To prevent abrupt decrease of revolution speed during reduction gear shifting or speed reduction shock by constituting to automatically control the revolution speed during gear shift to a proper value in accordance with shifting position of the gear box and car speed. CONSTITUTION: Normal injection volume arithmetic circuit 107, which inputs rotational speed signal S 2 from rotational speed sensor 101 and accelerator position signal S 3 from accelerator position sensor 102 and calculate injection volume and outputs normal injection signal S 8 , is equipped. On the other hand, rotational speed N g corresponding to the shifting position and car speed is calculated in accordance with predetermined formula by car speed signal S 4 from car speed sensor 103 and gear position sensor 104, and gear shifting period injection volume calculation circuit 108, which outputs injection volume signal under gear shifting S 9 , is installed to obtain the N g . And when shifting is decided by decision circuit 110, change-over circuit 109 is shifted to B-side, and the actuator 114 is controlled by gear shifting period injection volume signal S 9 . COPYRIGHT: (C)1982,JPO&Japio

An experiment relating to rotational remanent magnetization and frequency of demagnetizing field

Abstract: Summary. Several tests have been carried out to investigate how the generation of rotational remanent magnetization depended on the frequency of the applied demagnetizing field. The equipment used is described. The investigation was carried out using two specimens, one being a synthetic specimen of magfietite, and the other a cylindrical rock sample. These specimens gave virtually identical behaviour with varying frequency, unlike the differing behaviours reported previously by Wilson & Lomax. For each of the separate alternating field frequencies used (ranging from 50 to 1210 Hz), as the rotational speed of each specimen was reduced from 0.1 cycle s-l, the corresponding rotational remanent magnetization increased to a maximum value when the rotational speed was in each case just a little greater than 0.01 cycle s-', after which the rotational remanence decreases as the rotational speed decreases.

Motor speed control circuit

Abstract: A motor speed control circuit, for example, for the turntable drive motor of a phonograph record player, is of the type having a phase-locked loop including a frequency-divider with a dividing ratio which is changeable for altering the rotational speed of the motor, for example, so as to selectively establish turntable speeds of 45 rpm and 331/3 rpm, and has the gain of one of the components of the phase-locked loop, such as, the servo-amplifier, the loop filter or the phase comparator, varied in accordance with changes in the dividing ratio of the frequency-divider so that the loop gain of the phase-locked loop is maintained substantially constant regardless of the rotational speed of the motor.

Apparatus for controlling an internal combustion engine

Abstract: The fuel-air mixture of an engine in a motor vehicle is controlled on the basis of a signal related to the fluctuations in the cyclic variations of the average combustion chamber pressure. This signal is derived indirectly from a sensor which monitors the rotational speed of engine members, e.g. the crankshaft. In order to provide closed-loop control, there is provided a reference value which is adapted continuously to changing engine speed. In addition, a correction of the reference signal is made to account for varying degrees of damping induced by changing inertial masses coupled to the engine, in particular the elements of the transmission connected between the engine and the vehicle. The correction for damping is made on the basis of signals related to the prevailing gear ratio either by direct indication of the gearshift lever position or by measuring the rotational speeds of the input and output shafts of the transmission.

Vehicle spray gun motor speed control device - utilises optical head assembly to detect rotational speed of patterned disc

Abstract: The speed of a fluid motor is controlled by an optical feedback system to control a spray gun for the final coating on a motor vehicle. The speed takes account of the coating characteristics and the variable loading effects. The fluid motor comprises an output shaft on which an atomiser is mounted. A supply tube provides the coating material from one of several sources via contr controls and is sprayed onto an object which is at an electrostatic potential. An optical head assembly contains an optical fibre to conduct light from a source. An optical receiver mounted within the motor casing provides a signal reflected from a pattern on a disc on the motor shaft. Electronic circuits respond to the received light to compare rotational speed with a time base to provide a speed control signal for the motor.

Control device and method of controlling the rotational speed of a portable power tool

Abstract: A speed control device for portable power tools having particular applicability to electric drills. The speed control device is adapted to automatically adjust the speed of the motor (15) in accordance with changes in the diameter of the tool bit used. The device includes a sensor that senses the opening and closing of the jaws of the chuck. The sensor is mechanically coupled to a potentiometer circuit (30) whose output signal is varied in accordance with movement of the sensor. The output signal of the potentiometer circuit (30) controls the firing angle of a thyristor (34), which in turn controls the current supplied to the motor. In addition, the preferred embodiment includes a speed select switch (SW1) which is connected to the potentiometer circuit (30) to set the appropriate speed range for the motor, given the particular type of work material.

Suction system of internal combustion engine

Abstract: PURPOSE:To enhance a charging efficiency of intake air, by constructing and arranging an air space, linked to the intake pipe in a prescribed rotational speed range, in the intake pipe of the internal combustion engine, and operating an inertia supershrging in its rotational speed range CONSTITUTION:To a combustion chamber 8, in the top portion of a piston 9, is linked an intake path 1 through an intake valve 5 To this path 1, is linked an air space 2, having a prescribed capacity, through a switching valve 4 The switching valve 4 is opened when in a range of maximum rotational speed or in a generation of maximum torque of the engine by a controller not shown in the drawing And in this period, the intake path capacity is increased, and an inertia supercharging is operated by an intake air flow

Two-speed single phase motor with centrifugal switch

Abstract: A two-speed single phase motor of the capacitor-start type is disclosed wherein the motor is switched from the start condition to the run condition by means of a single contact centrifugally actuated switch. The motor comprises high speed and low speed main windings and high speed and low speed start windings wound on the stator core and a double throw selector switch for connecting the high speed main and start windings to the terminal or the low speed main and start windings to the terminals when the motor is operated in the high speed and low speed configurations, respectively. A single pole single throw centrifugally actuated switch connected to the rotor has a single contact pair connected in series with the start capacitor and one of the terminals, and the switch contacts open when the rotor exceeds a predetermined rotational speed to disconnect the start capacitor from the circuit. The same centrifugal switch contact pair is used in both the high speed and low speed configurations. A run capacitor may be connected in series with the high speed start winding in accordance with one embodiment of the invention. In an alternative embodiment, the run capacitor may be connected in series with both the high speed and low speed start windings so that the motor operates as a capacitor-start capacitor-run motor in both the high speed and low speed configurations.