Showing papers on "Rotor (electric) published in 1974"

Applied Aerodynamics of Wind Power Machines

Abstract: This chapter reviews the aerodynamics of various types of wind power machines and indicates advantages and disadvantages of various schemes for obtaining power from the wind. Propeller-type wind turbine theory is reviewed to the level of strip theory including both induced axial and tangential velocities. It is intended that this publication be of use in rapid evaluation and comparative analysis of the aerodynamic performance of wind power machines. The success of wind power as an alternative energy source is obviously a direct function of the economics of production of wind power machines. One of the key areas associated with development of wind power is rotor dynamics. A Savonius rotor requires 30 times more surface for the same power as a conventional rotor blade wind turbine. The Madaras rotor works on the principle of the Magnus effect. The Darrieus rotor has performance near that of a propeller-type rotor and requires power input for starting.

Thermal actuated valve for clearance control

Abstract: A shroud closely surrounding a high thermal inertia rotor is provided with a support structure having low thermal inertia characteristics. The support structure is selectively exposed to different temperature mediums during transient operation by way of a thermal actuated valve so as to cause a rapid growth thereof during periods of engine acceleration and a slow shrinkage thereof during periods of deceleration of the engine. In this manner the clearance relationship between the shroud and enclosed rotor is maintained at a minimum during periods of steady-state and transitional operation to thereby increase the efficiency of the combination.

Automotive alternator and solid state regulator tester

Abstract: A tester for a solid state voltage regulator includes two parallel branches available for interconnection to the two output contacts of the voltage regulator. The two branches both interconnect to the high voltage side of a battery. One of the branches includes a resistor in parallel combination with an indicator bulb. One of the branches includes a normally open switch. For use with automobile alternators having a built-in regulator, the tester can be connected directly to the regulator and test both the regulator and the alternator. When the regulator is independent of the alternator, it can be tested by itself by using actual rotor current available from an alternator used in conjunction with the tester. The on/off condition of the indicator bulb, when the switch and various contact terminals are interconnected, provides an indication of the effective operation of the regulator. A volt meter can be included integrally with the tester to provide output readings of the regulator.

Spectrum of rotor noise caused by atmospheric turbulence

Abstract: The spectrum of blade leading and the associated noise caused by interference of a propeller, helicopter rotor, or fan rotor with inlet turbulence are studied experimentally and theoretically. One test with hot‐wire anemometers in a static inlet and another test with pressure transducers on the blades of a fan rotor reveal inlet turbulence to be highly anisotropic. The intensity of the transverse velocity component was found to be 2.5% of the mean flow and the streamwise component was 0.9%, with ambient winds of about 2 mph. The transverse integral scale of the turbulence is a fraction of an inlet diameter, while the streamwise integral scale is over 100 diameters. Evidence indicates the source of these disturbances is atmospheric turbulence. The associated noise is partially coherent with spectrum peaks which are so narrow as to be difficult to distinguish from true harmonics. A novel blade loading model is developed using concepts from random pulse modulation theory. Theoretical spectrum predictions ind...

Refrigeration system and control therefor

Abstract: A refrigeration system is disclosed as comprising a compressor driven by an electronically commutated D.C. motor for circulating a suitable coolant through a condenser and then an evaporator disposed within a chamber or compartment to be cooled. The system is particularly adapted for use as an air conditioning system for automobiles and recreational vehicles, as portable refrigerating apparatus in recreational vehicles, and refrigerating apparatus for trucks or other transport vehicles. In such applications, a power source such as a battery, alternator, or generator (or rectified alternating current) serves to energize the motor. The motor may be operated by an electronic commutating circuit responsive to the position of the rotor of the D.C. motor for efficiently commutating the energizing signals applied to the stator windings of the brushless D.C. motor. The level of energization is set in accordance with the desired temperature to be maintained by the refrigeration system, whereby the D.C. motor is energized to drive the compressor at a selected speed corresponding to the desired temperature. The degree of stator energization may be controlled by: 1) regulating the output of the power source, or 2) regulating directly the commutating circuit to control the current signals applied to the stator windings.

Wind motor rotor having substantially constant pressure and relative velocity for airflow therethrough

Abstract: A method of generating power from wind comprising providing a turbine in an airstream with the turbine having a rotor with a plurality of blades and a stator with a plurality of blades upstream of the rotor. A portion of the ambient airstream is increased in velocity and reduced in pressure by passing such portion of the ambient airstream through the stator to provide an incoming airstream. The incoming airstream is passed through the rotor to drive the rotor and to provide an exiting airstream. The exiting airstream is conducted through a duct to increase the pressure and decrease the velocity of the exiting airstream, and subsequently the exiting airstream is discharged from the duct to the atmosphere.

Water filter assembly

Abstract: A low cost water filter apparatus including a valve rotor rotatable within a valve housing which rotor may be rotated within the valve housing when necessary for the purpose of engaging a bypass safety feature, or for the purpose of shutting off the flow of water through the filter unit prior to changing the filter element.

Dynamics of tilting proprotor aircraft in cruise flight

Abstract: A nine degree-of-freedom theoretical model is developed for investigations of the dynamics of a proprotor operating in high inflow axial flight on a cantilever wing. The basic characteristics of the rotor high inflow aerodynamics and the resulting rotor aeroelastic behavior are discussed. The problems of classical whirl flutter, the two-bladed rotor, and the influence of the proprotor on the stability derivatives of the aircraft are treated briefly. The influence of various elements of the theoretical model is discussed, including the modeling used for the blade and wing aerodynamics, and the influence of the rotor lag degree of freedom. The results from tests of two full-scale proprotors - a gimballed, stiff-inplane rotor and a hingeless, soft-inplane rotor - are presented; comparisons with the theoretical results show good correlation.

Segmented stator for progressive cavity transducer

Abstract: This invention relates to progressing cavity fluid motors with multiple segmented stator elements connected in series to provide a fluid passageway from the input to initial stator of the series to the terminal stator of the series; the rotor elements in each stator are connected together for simultaneous rotation.

Electric rotating machine

Abstract: An electric rotating machine including a rotor-stator device having a permanent magnet symmetrical rotor and a stator structure. The stator is in capsule form and has a pair of pole pieces and a magnetic flux transmitting structure for transmitting flux to the pair of pole pieces. The flux transmitting structure includes a pair of support members between which the rotor and stator structure are supported. The rotor is journaled for rotation in the support members. A rotatable gear assembly is supported on at least one of the support members and spaced from the rotor and stator structure to provide selective speeds in response to the rotation of the rotor. In one described embodiment the magnetic flux transmitting structure may comprise a generally U-shaped structure.

Brushless D.C. motor

Abstract: The permanent magnet rotor of a brushless d.c. motor is provided with regions of reduced magnetization in the mid-portion of the poles and spaced from the pole gaps, these regions being offset towards the extremity of the rotor where a portion of the rotor extending beyond the air gap of the motor serves to control a Hall I C sensor for control of the current in the stator windings. The regions of reduced magnetization do not interfere with the rapid switching of the Hall I C, but in a cylindrical air gap motor reduce the axial thrust on the rotor resulting from the asymmetric extension of the rotor out of the air gap which is provided for commutation control. Since this thrust is of a pulsating character, its reduction is important and permits simpler bearings to be used for the rotor shaft. Apart from reducing the axial thrust, the pattern of magnetization above described reduces non-uniformity in the current flow in the windings and therefore also variation in torque during a revolution of the motor. The latter advantages are also obtainable with flat air gap motors.

Sound radiation from a subsonic rotor subjected to turbulence

Abstract: The broadband sound radiated by a subsonic rotor subjected to turbulence in the approach stream has been analyzed. The power spectral density of the sound intensity has been found to depend on a characteristic time scale-namely, the integral scale of the turbulence divided by the axial flow velocity-as well as several length-scale ratios. These consist of the ratio of the integral scale to the acoustic wavelength, rotor radius, and blade chord. Due to the simplified model chosen, only a limited number of cascade parameters appear. Limited comparisons with experimental data indicate good agreement with predicted values.

Rotor for rotating wing type aircraft

Abstract: An improved rotor for a helicopter comprises a yoke at the inner end of each arm engaging the rotor hub by way of a spherical abutment

Catalytic reactor having disk-shaped, rotor-stator, reaction surfaces

Abstract: Apparatus for the continuous treatment of substances in flowable form in conjunction with a catalyst for carrying out chemical reactions, the apparatus including a rotor and a stator in opposed relationship defining between opposing working surfaces a reaction area with an inlet thereinto and an outlet therefrom, and the working surface of the rotor being in the form of a plurality of radially disposed lands and valleys with the lands including catalyst means for catalytically reacting with the substances during the rotation of the rotor.

Plastics rotor blade

Abstract: A plastics rotor blade, particularly for a helicopter, is formed with elongate filaments or rovings forming a loop for securing to a hub pin. The loop contains a metal socket secured to an extension extending between the loop walls.

Method of and apparatus for preventing leading edge shocks and shock-related noise in transonic and supersonic rotor blades and the like

Abstract: This disclosure is concerned with novel rotor blade and similar foil designs that, by critical skewing of intermediate blade regions where the airflow is supersonic, prevents leading edge shocks and shock-related noise.

An application of Floquet theory to prediction of mechanical instability

Abstract: The problem of helicopter mechanical instability is considered for the case where one blade damper is inoperative, and it is shown that if the hub is considered to be nonisotropic, the equations of motion have periodic coefficients which cannot be eliminated. The Floquet transition matrix method is shown to be an effective way of dealing with the nonisotropic hub and nonisotropic rotor situation. Time history calculations are examined and shown to be inferior to the Floquet technique for determining system stability. It is shown that instabilities which occur when one blade damper is inoperative may consist of nearly pure blade motion or they may be similar to the classical mechanical instability.

Energy absorbing unit for physical exercising devices

Abstract: An energy absorbing unit for physical exercising devices is arranged as an asynchronous motor the stator of which has windings to be connected to an AC supply and cooperates with the rotor of ferromagnetic material having a circular circumference, and an input shaft and an epicyclic gearing arranged inside the rotor circumference operatively connecting the input shaft to the rotor with the input shaft adapted to be driven by the training person, in order to generate an electromagnetic motive force on the rotor to tend to drive it in the direction opposing movement of the shaft by the training person and thereby act as a braking force on the shaft independently of the movement thereof.

Disc brakes with cooling rods

Abstract: Disc brake structure which includes a rotor presenting two spaced walls with a plurality of rods connected to the interior surfaces thereof so that air passing from the center of the rotor between the interior surfaces of the rotor walls and outward from the rotor is constrained to follow a substantially tortuous path.

Thermal Tracking-A Rational Approach to Motor Protection

Abstract: Motors of modern design have less tolerance to overloads than their predecessors. In addition, present-day applications tend to utilize the maximum capability of motors. Induction -motor stator insulation or rotor bars may be severely damaged by over temperature due to repeated starts, locked rotors, cyclic loads and other conditions for which existing overload devices do not provide adequate protection.

Staged expansion system as employed with an integral turbo-compressor wave engine

Abstract: The Present system provides for expanding high pressure gases from the chambers of a moving rotor and reentering said gases into the chambers of said moving rotor in such a way that the gases in the chambers of said moving rotor have been subjected to more expansions than the gases reentering the chambers and therefore are at a lower pressure than the gases reentering said chambers.

Supercharger system for combustion engine

Abstract: A supercharging system for a vehicle having an internal combustion engine comprises a shaft carrying a gas turbine rotor at one axial end and a centrifugal air compressor rotor at the other axial end. A pair of bearings mounting the shaft for rotation in a housing are adapted to be attached to the vehicle, the housing at one axial end a turbine nozzle ring and a turbine exhaust ring cooperable with the turbine rotor, and having at the other axial end an axially located compressor inlet member and a radially located compressor outlet member cooperable with the compressor rotor. The turbine nozzle ring is adapted to be connected to the exhaust manifold of the engine and the compressor outlet member is adapted to be connected to the intake manifold of the engine thereby supercharging the same. Finally, an electrical generator is integrally incorporated into the housing for generating electrical power when the shaft is rotating, the generator comprising a generator rotor mounted on the shaft between the bearings, and a generator stator mounted in the housing in cooperative relationship with the generator rotor.

Synchronous Machine Operational Impeadances From Low Voltage Measurements at the Stator Terminals

Abstract: Models of a synchronous machine for use in stability studies have been derived by measurements off-line at standstill. The method involves accurate determination of magnitude and phase of the impedance as seen at the stator terminals, for a range of frequency from 0.005 to 100 Hz. The data obtained pertains particularly to establishment of parameters for equivalent rotor circuits of varying degrees of complexity.

Remote controlled actuation system for the rotor of a gas turbine engine

Abstract: An actuation system is provided for the rotor of a gas turbine engine and includes an electric motor mounted for rotation with the engine rotor together with a generating system consisting of rotor windings which connect electrically to drive the motor, and stator windings which fixedly connect to the stationary portion of the engine. The stator windings may be energized in a controlled manner to induce an electromotive force in the rotor windings and thus provide a power and control signal to drive the electric motor at a controlled speed or direction.

Satellite momentum wheel

Abstract: The invention provides a satellite momentum wheel with passive magnetic centering means, between a stator and a rotor comprising at least one passive radial magnetic centering device, at least one axial magnetic centering device slaved to an axial velocity sensor and to an axial position sensor, at least one centering motor-generator unit having a magnetized rotor and a stator with toroidal windings switched by an angular rotation position sensor, at least one damping device, two emergency taper pivots for safe centering of the axial mounting of the rotor one of which is possibly in contact with a doped-polyamide step bearing on the stator, and interconnecting means between the wheel rim and the axis of said pivots employing a so-called coated arrayed-thread type cycloprofile structure.

Lubricated radial bearing assembly

Abstract: Apparatus for supporting a rotor assembly of a gas turbine engine is disclosed. A lubricated ball type thrust bearing which supports one end of the rotor shaft is disposed within a bearing compartment formed between the rotor assembly and the engine stationary structure. One or more carbon seals, in operative relation to a seal plate on the rotor assembly, prevent the flow of excess ambient engine air into the compartment. Lubricating and cooling oil is supplied to the compartment where it is positively apportioned between the bearing and the seal plate.

Apparatus for converting sea wave energy into electrical energy

Abstract: An apparatus for converting sea wave energy into electrical energy, comprising a buoy which executes periodic forced vibrations, with a natural frequency approximating the wave frequency, along the vertical axis of the buoy in a manner that the buoy moves with respect to the wave surface, and a turbogenerator for converting the air flow stream kinetic energy into electrical energy. The buoy is provided with an air chamber and a hydraulic piston, the air chamber communicating through an air duct with the turbogenerator. The latter includes a generator, a turbine stage with a stator and a rotor mounted on the same shaft with the generator. The turbogenerator turbine stage is provided with a supplementary stator disposed downstream of the turbine rotor and made symmetrical with the turbine stage stator with respect to the plane of rotation of the rotor.

Brushless cascade alternator

Abstract: A brushless a.c. generator is described which has a mode of operation similar to two wound-rotor induction machines connected in cascade. This cascade machine, which has previously been considered for application as a motor, has single stator and rotor windings in a conventional induction-machine frame. The machine is one of inherently high pole number. As an alternator, therefore, it is suitable for the generation of medium- to high-frequency supplies. The direct excitation current and the alternating output current flow in its one stator winding. Its cylindrical rotor iswound with an extremely simple short-circuited polyphase winding. Since no brushes, slip rings or rotating diodes are needed, the machine may be driven reliably at high speeds. A theoretical treatment is developed which takes account of magnetic saturation both in the steady state and in the transient state. Design and performance details of a prototype 400 Hz, 3000 rev/min., 3-phase machine are also included.