Showing papers on "Rotor (electric) published in 1979"

Computation of torque and current in doubly salient reluctance motors from nonlinear magnetisation data

Abstract: The paper presents a new method for accurately calculating the torque and current of a variable-reluctance stepping motor from measured or computed flux-linkage/current/rotor position data. The new method is more accurate and uses less input data than previously known procedures, and is computationally efficient. It can be applied to both steady-state and transient problems.

Multi-mode control system for wind turbines

Abstract: A multi-mode electronic wind turbine control system establishes a reference blade angle for a two-bladed, horizontal axis, variable pitch wind turbine rotor, the blade angle being regulated by a hydraulic pitch change mechanism. The rotor, via appropriate shafts and a gearbox, is coupled to a synchronous generator to produce electrical energy which is fed to a power utility grid. The control system provides closed loop pitch control for rotor acceleration rate during start-up, for rotor deceleration rate during shutdown, for speed control when the synchronous generator is off-line, and for power control when the synchronous generator is on-line. A single control integrator is used for all closed loop operating modes, with a rate limiter circuit in front of the control integrator to prevent integrator overtravel. The integrator has maximum and minimum blade angle stops, the minimum stop being variable as a function of rotor speed and wind speed. When on-line, power control is provided by a unique shaft torque control using proportional plus integral plus derivative controls in combination.

Fuselage surface pressure measurements of a helicopter wind-tunnel model with a 3.15-meter diameter single rotor

Abstract: A wind-tunnel investigation was conducted to measure the time averaged fuselage surface pressures of a helicopter model with a 3.15 meter diameter, four-bladed articulated rotor. Measurements were made at hover and advance ratios of 0.05, 0.15, and 0.20 for a range of thrusts. Data are presented with no analysis.

Inverter Drive for Doubly Salient Reluctance Motor: Its Fundamental Behaviour, Linear Analysis and Cost Implications

Abstract: A variable-speed drive using a doubly salient variable reluctance motor, because of its ability to operate efficiently from unidirectional winding currents, enables the number of main switching devices in the inverter to be halved, yielding a very economical brushless drive. The drive is analysed using a linear model for the motor, yielding phase-current waveforms which enable an economical design for the thyristor inverter and provide guidance for a motor design which will optimise the performance/cost ratio of the drive as a whole. A control strategy for firing and turning off the inverter thyristors at appropriate rotor angles for a traction application also emerges from the analysis. Experimental waveforms exhibit shapes similar to those predicted, and the results of this analysis have been of great value in designing such a drive for a battery vehicle.

Noise of a model helicopter rotor due to ingestion of turbulence

Abstract: A theoretical and experimental investigation of the noise of a model helicoper rotor due to ingestion of turbulence was conducted. Experiments were performed with a 0.76 m dia, articulated model rotor for a range of inflow turbulence and rotor operating conditions. Inflow turbulence levels varied from approximately 2 to 19 percent and tip Mach number was varied from 0.3 to 0.52. Test conditions included ingestion of a atmospheric turbulence in outdoor hover as well as ingestion of grid generated isotropic turbulence in the wind tunnel airstream. In wind tunnel testing, both forward flight and vertical ascent (climb) were simulated. Far field noise spectra and directivity were measured in addition to incident turbulence intensities, length scales, and spectra. Results indicate that ingestion of atmospheric turbulence is the dominant helicopter rotor hover noise mechanism at the moderate to high frequencies which determine perceived noise level.

Centrifuge rotor and collapsible separation container for use therewith

Abstract: A centrifuge rotor for use in the continuous separation of a liquid into fractions has a recess for receiving a flow-through separation container. The recess has interrupted annular shape with inclined side-walls. The inclination of the sidewalls and the cross-sectional area of the recess increase continuously in the circumferential direction from one end of the recess to the other. A collapsible flow-through separation container having flexible inlet and outlet tubes is adapted to fit within the rotor recess. Its cross-sectional area increases continuously from the inlet end to the outlet end.

Observations on the Influence of Rotation on Heat Transfer in the Coolant Channels of Gas Turbine Rotor Blades

Abstract: This paper reports the results of an experimental study of the combined influence of Coriolis acceleration and centripetal buoyancy on heat transfer in a cylindrical tube which rotates about an axis orthogonal to its axis of symmetry. It is demonstrated that for a radially outward flow, Coriolis acceleration tends to improve heat transfer. However the Coriolis-induced improvement to heat transfer may be nullified and reversed due to centripetal buoyancy and this is demonstrated. Proposals are made which permit an overall assessment of these two interacting effects to be made. The implications of the results reported in relation to the design of conventionally cooled turbine rotor blades are discussed.

A simplified rotor system mathematical model for piloted flight dynamics simulation

Abstract: The model was developed for real-time pilot-in-the-loop investigation of helicopter flying qualities. The mathematical model included the tip-path plane dynamics and several primary rotor design parameters, such as flapping hinge restraint, flapping hinge offset, blade Lock number, and pitch-flap coupling. The model was used in several exploratory studies of the flying qualities of helicopters with a variety of rotor systems. The basic assumptions used and the major steps involved in the development of the set of equations listed are described. The equations consisted of the tip-path plane dynamic equation, the equations for the main rotor forces and moments, and the equation for control phasing required to achieve decoupling in pitch and roll due to cyclic inputs.

Phase lock loop commutation position control and method

Abstract: A phase lock loop commutation position control and method for a drive system for a DC field motor having a rotor and a plurality of stator windings is disclosed. Electric power is supplied to the stator windings in accordance with gating signals. The gating signals are generated in accordance with timing signals, which are provided in response to a clocking signal. A position signal is furnished as a function of the position of the rotor with respect to a preselected stator position. An error signal is generated proportionally to the phase difference between a preselected timing signal and the position signal. The clocking signal is produced as a function of the error signal. The invention also can include a shift signal produced as a function of the rotation of the rotor. The shift signal is added to the error signal effectively to cause the preselected timing signal to be advanced with respect to the position signal. In addition, a shift signal can be produced as a function of the current level of the electric power, and this shift signal can be added to the error signal effectively to cause the preselected timing signal to be advanced with respect to the position signal. The invention can also cause the timing signals to be provided for generating the gating signals in accordance with the position signal when the rotation of the rotor is below a preselected value.

Pole-by-Pole d-q Model of a Linear Induction Machine

Abstract: The concept of d-q coupled circuits representing stator and rotor magnetic poles is widely used in the analysis of symmetrical round-rotor induction machines. In this paper conventional round-rotor theory is extended to the analysis of linear induction machines. In particular, a tenth order set of differential equations are derived which describe a basic model for a four pole machine. Higher order systems of equations are discussed which better incorporate leading and trailing end effects. The parameters used in the model are readily derived from classical round-rotor theory. The resulting model is inherently capable of simulating both steady-state and transient behavior.

Compact variable speed drive for electric motor

Abstract: An electrical machine in which a frame supporting the rotor windings is coupled to the machine shaft through a planetary gear system housed within the rotor structure. The internal ring gear of the planetary system forms a part of the motor rotor structure. Further locking devices are provided to lock the various movable components making up the drive system together or to the motor casing so that a variety of speeds can be selectively attained at the output shaft or shafts of the motor without changing the motor speed.

Investigation of Squeeze-Film Isolators for the Vibration Control of a Flexible Rotor

Abstract: This paper describes work in which the feasibility of controlling the synchronous and non-synchronous vibrational behaviour of a flexible rotor was investigated using squeeze-film isolators in seri...

Underwater slow current turbo generator

Abstract: A self-contained electrical generating device for placement in a naturally flowing stream The generating device converts the kinetic energy generated by fluid flow or gravity contained within the flowing stream whether river or ocean current into useful electric energy using blade configuration and placement to maximize the usable energy The present invention also using auxiliary means to increase the rate of flow of the fluid by the blades of the generator thus increasing the energy capable of conversion The rotor and the stator are located radially outwardly from the rotating hub of the generating system and are supported by spoke like legs thus greatly reducing any resistance to water flow, minimizing the disturbance to the flowing stream and maximizing the relative linear velocity between the rotor and the stator

Applying photoresist onto silicon wafers

Abstract: Applying photoresist to silicon wafers in the manufacture of integrated circuit chips by carrying the wafers upon a rotor in a chamber and spraying from a plurality of nozzles in the chamber toward the rotor for application to the wafers.

A multipolar resolver

Abstract: A multipolar resolver having a substantially cylindrical rotor of magnetic material with A· n rotor poles (12, B 1 -B 10 ) provided equidistantly on the outer periphery thereof, a stator of magnetic material with B n stator poles (P 1 -P 8 ) provided equidistantly along the circumference concentric with the axis of said rotor, and a central coil (15) provided on said stator along substantially the same axis as said rotor axis. A, B and n are positive integers and the value of A differs from the value of B by one such that |A-B| = 1. In order to provide a multipolar resolver which requires no coils on the rotor and which permits an increase in the number of poles of the resolver without a corresponding increase in complexity and manufacturing cost, sine and cosine coils (16, S 1 -S 4 ; 17, C 1 -C 4 ) are wound alternately on circumferentially successive ones of the stator poles (P 2 , P 4 , P 6 , P e ; P 1 , P 3 , P 5 , P 7 ). Circumferentially successive ones of the sine coils (16, S 1 -S 4 ) are connected in series with each other and are wound in opposite directions of winding alternately and circumferentially successive ones of said cosine coils (17, C 1 -C 4 ) are connected in series with each other and wound in opposite directions of winding alternately.

Wind power conversion and control system

Abstract: A combination wind rotor and output energy transducer to provide output energy from the system and to automatically regulate the wind rotor at all wind velocities to thereby allow the wind rotor to operate at a constant tip speed/wind velocity ratio and at its maximum efficiency. The energy transducer is a combination of positive displacement hydraulic pump and an orifice in the hydraulic system to generate heat. Overspeed protection is afforded by maximum hydraulic loading of the wind rotor in extreme wind conditions. A wind rotor steering system by which the wind rotor is oriented into the wind at all wind velocities. The wind rotor restoring torque is automatically in balance with its reaction torque.

Capacitive angular displacement transducer for remote meter reading

Abstract: A capacitive angular displacement transducer having a rotor plate and a first and second stator plates is disclosed. The rotor plate is coaxially mounted between, and parallel to, the first and second stator plates. The first stator plate is divided into four excitation areas each being impressed with a sinusoidal excitation voltage having a different phase angle. The rotor plate has a first face having two conductive patterns. The two conductive patterns act as resolvers to produce resultant voltages from the vector addition of the voltages variably capacitively coupled thereon due to the excitation voltages. The rotor plate has a second face having two annular conductive areas electrically connected to the conductive patterns of the first rotor face. The second rotor face together with the second stator plate form a constant capacitive pickup for the resultant voltages produced by the two conductive patterns of the first rotor face.

Horizontal axis wind generator having adaptive cyclic pitch control

Abstract: Cyclic pitch variation of the rotor blades of a horizontal axis wind energy conversion machine permit its operation at substantially design rotor speed and rotor torque over a range of wind speeds, by heading the rotor progressively out of the wind through a range from approximately 20° for light winds to a near 90° setting for gales, at which the power output is interrupted to permit the rotor to idle. Changes in wind direction will cause the rotor to follow the wind even though so headed out of it. By allowing the blades substantial freedom to adapt their pitch to side winds, the present construction allows rapid rates of yaw into a shifting wind, such as may destroy conventional rotors by the attendant gyroscopic forces. Further, by actively controlling their pitch, aerodynamic forces exerted by the cyclic pitch change blades substantially balance out the gyroscopic forces attendant to yaw. The preferred rotor uses only two blades mounted on a common shaft which oscillates cyclically in the hub. Since cyclic variation of blade pitch establishes a cyclic pitch center of rotation offset from the rotor axis; by moving this offset the rotor is caused to yaw at a controlled rate in a desired sense.

Visualization of Flow during the Processing of Rubber in an Internal Mixer

Abstract: The flow visualization method of studying internal mixing has been shown to be a powerful tool for determination of the critical factors influencing flow and mixing efficiency. Correlation of visualizations with results obtained for “practical” rubber mixing confirms the validity of the method for the prediction of flow in conventional mixing operations. Fill factor is identified as one of the key variables influencing mixing uniformity. At this stage it is not possible to make general recommendations since only limited studies were carried out. However, from the dependence of mix uniformity on fill factor derived from a B Banbury having two-wing rotors, fill factors of 0.7–0.8 are shown to give the best results. This range of fill factors provides an adequate and continual filling of the region in front of the rotor tip and ensures that the high stresses required for the fracture of particle material aggregates are generated. It also permits the formation of voids behind the rotor tips. Such voi...

Wind power generator

Abstract: A wind power generator comprising a vertically disposed support post having a support assembly rotatably mounted thereon which extends horizontally laterally therefrom. A plurality of vertically spaced rotor assemblies are rotatably mounted on the support assembly and are connected to an electrical generator so that electrical energy is generated as the rotors are rotated by wind. A wind deflector is mounted on each of the rotor assemblies for directing the wind towards to the rotor blades at a more efficient angle. The deflector also shields a portion of the rotor blades so that the wind is prevented from inhibiting the rotation of the rotor assembly. The rotor assemblies are maintained in a direction facing the wind by means of an adjustable stabilizer assembly.

Development of vertical axis wind turbines

Abstract: This paper summarises the work done at the National Aeronautical Laboratory (NAL) between 1975 and 1977 on the development of vertical axis wind turbines based on the Darrieus rotor. On the analytical side, a performance analysis was developed which permits the estimation of the characteristics of such machines. A 5 m high wind turbine using curved wooden blades was designed, fabricated and tested. Both the theory and initial tests confirmed the low starting torque of the turbine. Wind tunnel tests were performed on model Savonius rotors to determine optimum starter bucket configurations. Finally a straight-bladed turbine was designed and constructed. It is concluded from our experience that darrieus burbines are likely to be useful in large systems used to generate electrical power for the grid; for direct water pumping purposes, however, these turbines are unlikely to be suitable.

Commutatorless direct current motor drive system

Abstract: A commutatorless direct current motor drive system that initiates rotation of a permanent magnet rotor from standstill upon the application of supply potential and then sustains rotor rotation by sequentially energizing the polyphase stator phase windings in response to the alternating current potential waveforms induced in the stator phase windings by the magnetic field of the permanent magnet rotor upon rotor rotation.

Panemone wind turbine

Abstract: The disclosed wind turbine is designed to optimize power output at a given wind velocity without corresponding increases in cost. The rotor carries a plurality of vertical vanes arranged at an acute angle to diametric lines through the rotor and the inner edges of the vanes, which are spaced from the rotor center. Each vane carries a plurality of fins extending on opposite sides of the vanes. In one embodiment, a wind-collecting shroud is movable to position an open side thereof in the upwind direction and is shaped to direct the wind more efficiently toward the vanes and fins. In a second embodiment, each vane is bent on a vertical axis to include two portions, at least the inner of which carries wind-collecting fins, at different angles to the rotor diameter, and no shroud is used.

Directly cooled, rotating rectifier assembly for a synchronous machine

Abstract: A plurality of individual semiconductor diode wafers secured to the rotor of a synchronous machine rectify AC from an excitation power source to provide DC to the main rotating field element. The diode wafers, connected as either a half wave or a full wave rectifier, are contained within a housing to form a rectifier assembly. The assembly is mounted directly on an inner surface of the housing carried on the shaft of the machine. The assembly is provided with suitable passageways or surfaces for flow of a non-electrically conductive cooling medium. In one embodiment, the cooling medium, as oil or air, traverses the surface of the diode wafers to provide high efficiency heat removal. In another embodiment the cooling medium traverses a heat sink on which the wafers are mounted to provide a high efficiency heat removal.

Sliding caliper disc brake

Abstract: A pin type floating caliper disc brake for an automotive vehicle is disclosed in which the brake shoe assemblies transfer the braking torque directly to the anchor plate support. The caliper containing the hydraulic actuation piston is slidably supported upon pins extended inboard of the anchor plate support and carries no braking torque. The caliper assembly in combination with the anchor plate support are configured to permit brake shoe assemblies of varying areas and thickness and to accommodate solid or vented rotor designs without modification to the caliper or anchor plate support. The rotor may readily be removed without removal of the anchor plate support.

Actuator for heart pump

Abstract: A heart pumpconsisting of a housing having an inlet and an outlet and a diaphragm adapted to be reciprocated to cause flow of flood through the inlet and the outlet, a brushless dc motor mounted on the housing, the motor having a fixed ball screw nut and a ball screw mounted for axial movement with respect to the motor rotor while being fixed against rotation with respect to the rotor whereby rotation of the rotor causes the screw to move axially with respect to the motor thereby actuating the pump diaphragm.

Control system for a multi-phase motor

Abstract: A motor control system for use in a high speed teleprinter or the like for controlling the rotational position and movement of a rotor, and apparatus driven by the rotor, by detecting back EMF induced into an unenergized field winding by rotational movement of the rotor. The output and input terminals of a first amplifier responsive to a first motor control signal, and a second amplifier responsive to a second motor control signal, are reactively coupled such that the amplifiers respond to either motor control signal to develop a signal simulating the signal into an unenergized winding of the motor due to mutual inductance with an energized winding. A differential voltage comparator provides a feedback signal indicative of motor performance upon comparing the simulated signal with the signal actually induced. In the illustrated teleprinter application, the feedback signal is utilized to control energization of the carriage drive motor to assure accurate positioning of the teleprinter print head, and to provide an accurate indication of actual print head position to the signal processing circuitry of the teleprinter.

Programmed controller for ultrasonic testing

Abstract: A system for ultrasonically testing the material of a turbine rotor includes a drive unit for axially indexing and angularly orienting a plurality of crystal transducers through the bore of the turbine rotor under test; an ultrasonic tester for electronically activating the crystal transducers as they are indexed through the rotor bore to transmit ultrasonic signals which are propagated through the rotor material and for receiving the back reflected echo signals corresponding to the ultrasonic transmissions; and a programmed electronic controller electrically interfaced to the drive unit and ultrasonic tester for adaptively coordinating the operation thereof in a selected one of a plurality of control modes to observe generated anomaly indications and measured test data parameters from the drive unit and ultrasonic tester which are used to determine the size and location of a detected potential imperfection in the rotor material and to adaptively control the drive unit in accordance with a function based on the anomaly indications and observed measured parameters of the drive unit and ultrasonic tester. Accordingly, prespecified portions of the observed measured parameters are automatically recorded, at times, during the ultrasonic testing operations to provide information relating to the size and location of the potential imperfections.