Showing papers on "Rotor (electric) published in 1980"

Parameter Adaption for the Speed-Controlled Static AC Drive with a Squirrel-Cage Induction Motor

Abstract: The performance of speed-controlled induction motor drives, without a direct sensing of the flux, depends heavily on the accuracy with which the motor parameters are known. They change widely with the temperature, frequency, and current amplitude. With a control based on rotor position measurement and inner current control loops, the rotor resistance is the most essential changing parameter. A method of automatic adaption of the control to the changes in this parameter is presented. The proposed strategy is based on the measurement of only motor voltages and currents and is implemented by analog means. It does not make use of transducers or probes to measure the temperature or the flux in the motor.

Tip cap for a rotor blade and method of replacement

Abstract: A tip cap for a rotor blade which includes at least one radially extending rib having an abrasive coating thereon for providing a close clearance seal between the rotor blade and the surrounding shroud and also for cleaning the shroud of deposits of material thereon. The tip cap can include a cooling arrangement therein comprising a plurality of cooling passages and a thermal barrier. A method is provided for replacing one tip cap with another and includes the steps of removing a tip cap, machining the end of the rotor blade flat, aligning the replacement tip cap and securing it with the rotor blade.

Clock rate control of electronically commutated motor rotational velocity

Abstract: A speed control system for an electrically commutated motor which is readily adaptable to digital velocity control input and which provides highly efficient and accurate control in a relatively inexpensive manner. Desired motor rotational velocity is commanded by an input clock rate, which may be variable, rather than by a voltage or current signal. A sensor is provided for determining actual rotor position, and actual rotor position is periodically compared with instantaneous desired motor position as indicated by the time of occurance of one of the input clock signals or pulses. Depending upon the results of this periodic comparison, a dynamically established active current limit is modified. Specifically, if motor rotor actual position leads desired position, the current limit is reduced. If, on the other hand, actual motor position is lagging, the current limit is increased. If the rotor is at the correct position, or within a predetermined deadband, the current limit is unchanged. This control action occurs simultaneously with conventional winding commutation taking place under the control of a, commutation sequencer periodically advanced in conventional fashion as the rotor reaches each of a plurality of predetermined positions.

Hydrodynamic bearing system for a brushless DC motor

Abstract: A hydrodynamic bearing system for a motor. The motor is illustrated and described as driving a pump for an artificial heart. The motor stator has a cylindrical bore which is closed at one end. The rotor is slidable and rotatable in the bore. The rotor has affixed to its shaft an impeller with its outside diameter concentric to the rotor outside diameter. Both rotor and impeller are supported hydrodynamically such that the tendency is for the entire rotor/impeller assembly (the only moving element) to be completely suspended by fluid. The rotor can be rapidly reversed to provide heart pumping action or can be driven unidirectionally for artificial heart pumping action of another type. The fluid cannot easily escape from the closed end of the stator, thereby providing a dashpot effect which tends to keep the rotor from changing position. In moving away from the closed end, the rotor brings fluid between the end of the rotor and the closed end of the bore to act as a buffer or bearing fluid when reversal moves the rotor toward the closed end.

Alternator for wind generator

Abstract: An alternator for wind generator use employing a pair of stators having a rotor mounted therebetween in planar coaxial relationship. The stators have radially slotted coil forms integral therewith in which coils are wound in a serpentine fashion. The rotor is provided with an aluminum rim slotted in a radial manner inwardly of its periphery to hold permanent magnets, which magnets through the aid of the rim concentrate eddy currents in the coils in an improved manner.

Effects of primary rotor parameters on flapping dynamics

Abstract: The effects of flapping dynamics of four main rotor design features that influence the agility, stability, and operational safety of helicopters are studied. The parameters include flapping hinge offset, flapping hinge restraint, pitch-flap coupling, and blade lock number. First, the flapping equations of motion are derived that explicitly contain the design parameters. The dynamic equations are then developed for the tip-path plane, and the influence of individual and combined variations in the design parameters determined. The steady state flapping response is examined with respect to control input and aircraft angular rate which leads to a feedforward control law for control decoupling through cross feed, and a feedback control law to decouple the steady state flapping response. The condition for achieving perfect decoupling of the flapping response due to aircraft pitch and roll rates without using feedback control is also found for the hover case. It is indicated that the frequency of the regressing flapping mode of the rotor system can become low enough to require consideration in the assessment of handling characteristics.

Wind turbine-generator

Abstract: A wind-turbine generator system which transforms the rotational energy of a wind driven turbine blade into rotation in opposite directions of a rotor and a stator of a dynamoelectric machine to generate electrical power. A bevel gear rotating with the turbine blade drives two pinion gears and associated concentric shafts in opposite directions. The two shafts combine with a planetary gear set to provide the desired oppositely directed rotation. One of the shafts is associated with a ring carrier and drives a ring gear in one rotational direction. The other shaft drives a planet carrier in the opposite rotational direction. The planetary gear set is arranged such that a sun gear is driven in the direction opposite to that of the ring gear. A rotor is affixed to the sun gear by a spider support structure, and a stator, affixed to rotate with the ring gear, surrounds the rotor. The rotor and stator are thus rotated in opposite, mechanically and electrically additive, directions.

Blocking condition detection device in a medical fluid injection system

Abstract: A medical fluid injection system which includes a flexible conduit and a rotor for supplying a pressurized medical fluid to the human body through the flexible conduit. A blocking condition detection unit is provided for detecting an abnormal blocking condition of the flexible conduit. The blocking condition detection unit includes a supporting member for supporting the flexible conduit in a manner that the section of the flexible conduit is forced to show a rectangular configuration. A rod is slidably disposed through the supporting member so that one end of the rod makes contact with the flexible conduit. When an abnormal blocking condition occurs in the flexible conduit, the flexible conduit held by the supporting member expands to depress and shift the rod. The thus created movement of the rod is detected by a mcroswitch, whereby the rotation of the rotor is interrupted.

Brushless D.C. motor

Abstract: The invention relates to a collectorless D.C. motor with a horizontal air gap, particularly a low-speed motor for the direct drive of recording and/or reproducing devices. As per invention, the rotor axle is supported within an axial bore of the motor housing, with the motor housing made of plastic. The stator winding and the magnetic return structure are fixedly arranged on the motor housing which is also provided with bores for attaching the motor on installing it into the device. Obviating of machining sequences, simplification of assembly and direct support of the rotor axle in the motor housing all contribute to a reduction in manufacturing cost.

Combination microprocessor and discrete element control system for a clock rate controlled electronically commutated motor

Abstract: A motor velocity control system employing feedback to maintain actual motor rotational velocity at or near a desired rotational velocity implements a clock rate control motor rotational velocity system by advantageously apportioning the required functions between a relatively small, slow speed microprocessor, and a plurality of discrete circuit elements in the form of analog and digital logic devices. The microprocessor serves the following four general functions: (1) as a "basic clock" timer of variable rate to set up motor speed; (2) as a relatively slow speed determiner of when various components are to be switched for commutation, and for indicting to an integrator circuit which motor winding is currently unenergized and which therefore may be sampled for determining rotor actual position; (3) as a digital feed to a digital to analog (D/A) converter for setting a motor winding current limit; in accordance with the principles of the Alley; and (4) as a communication link to receive velocity and direction commands, preferably in the form of a plurality of points defining a waveform profile or envelope. Discrete analog and digital logic elements are employed to implement the functions of analog integration and comparison with the integral limit, as well as current comparison and chopper control.

Methods and apparatus for maximizing and stabilizing electric power derived from wind driven source

Abstract: The shaft of a wind turbine is connected to the rotor of a three-phase AC generator. The rotor windings, in turn, are connected to the rotor windings of a DC-energized, AC exciter via a differential frequency-converter. A frequency-detector, which monitors the output of the AC generator, is connected to the input of the frequency-converter to maintain the output of the generator at 60 Hz. A "real" power sensing circuit, connected to the output of the generator, develops a control signal which, when subtracted from a second control signal generated by a power management control circuit, maintains the power output of the generator at the maximum possible level for each particular power output from the wind turbine which drives the generator.

Rotor tip clearance control apparatus for a gas turbine engine

Abstract: A rotor tip clearance control apparatus for a gas turbine engine comprises an annular shroud member which forms part of the static structure of the apparatus. The shroud member has an internal frusto-conical surface which co-operates with the outer extremities of the rotor to define a small clearance. In order to control this clearance the shroud member is mounted from fixed structure by rotatable eccentrics which can move the member axially and thus affect the clearance in a predetermined manner.

Adjustable massage shower head

Abstract: An adjustable massage shower head comprising, a housing defining a liquid input chamber for receiving a liquid, a flow guide mounted for axial movement in the housing defining a liquid flow passage from the input chamber and a turbine chamber, the flow guide having a spray bottom connected thereto with openings therethrough. A rotor valve is rotatably mounted and fixed at an axial position to the housing and disposed in the turbine chamber for rotation which produces a pulsating spray from the openings. A ring wall is disposed around the turbine chamber and has a plurality of ducts extending radially at an oblique angle therethrough for directing liquid against the rotor valve. The flow guide is axially movable to direct liquid against increasing areas of the rotor valve to increase the frequency of the pulsing spray. A valve disc is also connected to the housing in the flow guide for diverting the flow of liquid from the turbine chamber to a second flow passage around the flow guide to form a continuous spray which is adjustable with further axial movement of the flow guide.

Adjustable vane windmills

Abstract: A system of rotatably and pivotally mounted radially extended bent supports for radially extending windmill rotor vanes in combination with axially movable radially extended control struts connected to the vanes with semi-automatic and automatic torque and other sensing and servo units provide automatic adjustment of the windmill vanes relative to their axes of rotation to produce mechanical output at constant torque or at constant speed or electrical quantities dependent thereon.

Apparatus for operating a motor vehicle

Abstract: An improved internal combustion engine arrangement for providing increased fuel efficiency, reduced pollution, and an improved starter and generator arrangement. An internal combustion engine having a flywheel for equalizing non-uniformities of engine output torque has a first conventional clutch for shifting gears, and a second controllable clutch between the flywheel and engine for selectively disconnecting and stopping the engine during certain operating states of the vehicle. A combined starter-generator is provided having a toothed, windingless rotor fixed on the flywheel periphery and a stator surrounding the rotor and provided with windings both for generating current, and for imparting rotational force on the flywheel, which in turn starts the engine.

Brushless DC motor

Abstract: A brushless DC motor having a rotor magnet magnetized to provide a sinusoidal magnetic field and two-phase stator windings at positions which differ from each other by an electrical angle which is an odd multiple of 90° is provided with a drive circuit comprising a signal generator with an output having a frequency determined by the rotational speed of the rotor, and a memory having stored therein digital information data converted from sampled values of a sinusoidal signal free of distortion The digital information data stored in the memory is read out therefrom by the output of the signal generator in synchronism with the magnetic field from the rotor magnet, and such read-out information data is employed to determine currents flowing through the stator windings so that torque ripple is substantially eliminated

Fault detection apparatus for rotor winding of rotary machine

Abstract: A fault detection apparatus for a rotor winding of a rotary machine comprises a peak value hold circuit, a peak value processor and a monitor. The peak value hold circuit holds peak value of a pulsing magnetic flux waveform supplied from a magnetic flux sensor mounted in proximity to a surface of a rotor, for a necessary time period. The peak value processor sequentially compares the peak value held in the peak value hold circuit with corresponding one of pre-stored peak values of the pulsing magnetic flux waveform to determine if a difference therebetween exceeds a preset level. The monitor indicates the presence or absence of fault based on the result of the comparison of the processor.

Process for centrifugal separation and apparatus for carrying it out, applicable to a mixture of phases of any states

Abstract: The invention relates to a process for centrifugal separation and to an apparatus for carrying it out, applicable to a mixture of phases of any states, said apparatus comprising, disposed coaxially and moved in rotation in a fixed enclosure, a fan adapted to create a depression upstream, a rotary distributor converting the pressure drop resulting from the action of the fan on the upstream pressure into a speed of rotation of the mixture added in the same direction to the positive speed of rotation of said distributor, and a rotor comprising elements for guiding running streams, trap elements which imprison still layers and pick up heavy particles, elements for conducting these latter.

Method of making rotor assembly having anchor with undulating sides

Abstract: A rotor assembly having wedge-shaped permanent magnets and anchors with undulating sides for attaching the rotor hub to the pole bodies.

Laser anemometer measurements in a transonic axial flow compressor rotor

Abstract: A laser anomometer system employing an efficient data acquisition technique has been used to make measurements upstream, within, and downstream of the compressor rotor. A fluorescent dye technique allowed measurements within endwall boundary layers. Adjustable laser beam orientation minimized shadowed regions and enabled radial velocity measurements outside of the blade row. The flow phenomena investigated include flow variations from passage to passage, the rotor shock system, three-dimensional flows in the blade wake, and the development of the outer endwall boundary layer. Laser anemometer measurements are compared to a numerical solution of the streamfunction equations and to measurements made with conventional instrumentation.

Rotary actuator assembly for disk drive head positioner

Abstract: A rotary actuator assembly for positioning read/write heads in disk drive mass storage systems. The actuator assembly includes an actuator motor and one or more actuator arms secured thereto. The motor provides rotary motion of the arms, to move the heads. The stator magnet of the motor is an electromagnet wound on an arcuate core; a pair of elongate permanent magnets are attached to the rotor member, for coaction with the stator magnet. The rotor member has a U-shaped cross sectional area in a plane perpendicular to its axis of rotation; the permanent magnets are fixed to the outside, bottom corners of the U and the actuator arms are mounted across the open end of the U. The rotor is of a very small radius, to minimize inertia. The permanent magnets have a flat face facing the stator, with a channel running longitudinally down the middle, to minimize flux density variations in the permanent magnet-coil gap. The rotor balances the arm relative to the rotor's axis. The arms are of a substantially symmetrical tapered truss design, presenting low inertia; each is cantilevered to the rotor by one bolt which is passed through and pulls the arm against the rotors. Additionally, a spirol-type cylindrical spiral spring, received in a slot in the arm, prevents lateral slippage of the arm relative to the rotor. A pair of cantilevered leaf spring crash stops fixed to the stator decelerate the rotor at the ends of its range of travel.

Method of making electric machines

Abstract: An electric machine, such as an induction motor, having a rotor and stator core formed of metal strip coiled about a centrally longitudinal axis extending generally normal to the plane of the strip, and wherein the strip is provided with depressions on longitudinally spaced locations along the length of the strip so as to enable coiling of the strip about the longitudinal axis.

Modular windmill installation

Abstract: A windmill installation adapted to extract energy from natural wind currents is disclosed wherein a plurality of individual wind wheel modules are stacked vertically in a tower-like structure and are interconnected with one another to operate in a unitary manner. Each module has a rotor assembly which is disengageable from the rotor assemblies of other modules without interrupting the generation of power from the installation. A rotatable windshield is provided about the rotor assembly for improving output efficiency of the wind wheel and protecting the rotor assembly from damage in the event of excessively high wind speeds. The angular position of the windshield is determined by an automatic control system responsive to wind speed and direction.

Nutating motor coupling

Abstract: A constant velocity coupling joint provides rotary motion to an output shaft of a nutating motor or shaft driven by a nutating member. A nutating plate is supported by the coupling and the nutating motion of the plate is transformed to rotary motion of the output shaft. The coupling includes a plurality of balls which are mounted in slots formed between a radially extending coupling plate fixed to the shaft and the nutating rotor member. The balls are held in position by a pair of thrust spacers positioned on each side of the coupling plate. The thrust spacers also provide rolling support for the nutating plate.