Showing papers on "Rotor (electric) published in 1972"

Rotating electrical machine having rotor and stator cooled by means of heat pipes

Abstract: A polyphase induction motor having a rotor and a stator, each having heat pipes incorporated therein, is disclosed. The stator is comprised of a stack of laminations having radial slots therein which contain heat pipes as well as electrical conductors. The stator heat pipes are located in the stator slots and extend axially to a remote location beyond the stator and the rotor. The stator heat pipes contain wicks and contain a twophase fluid coolant. The rotor is also comprised of a stack of laminations with radial slots located in the outer periphery thereof. Heat pipes are incorporated in the rotor slots and, like the heat pipes in the stator slots, extend axially to a remote location beyond the rotor and the stator. The rotor heat pipes also serve as electrical conductors as well as heat exchangers for cooling the rotor. Thus, all of the rotor heat pipes are electrically interconnected by end rings located at the axial extremities of the rotor. The rotor heat pipes also contain a two-phase fluid coolant. However, because centrifugal force promotes condensate return within the rotor heat pipes wicks need not be used in the rotor heat pipes. Cooling fins are provided on those sections (condenser sections) of the heat pipes which extend axially beyond the rotor and the stator thereby forming air heat exchangers. Moreover, the fins on the moving rotor heat pipes act as moving fan blades and, being located proximate to the cooling fins on the stator heat pipes, effectively form a single-pass, forced-convection, air heat exchanger.

Compact dynamic multistation photometer utilizing disposable cuvette rotor

Abstract: A compact analytical photometer of the rotary cuvette type designed to use small disposable cuvette rotors. A power driven cuvette rotor holder having a generally flat, circular configuration is provided with an integral, upstanding, annular lip for receiving, in an easily insertable and removable fashion, small disposable cuvette rotors. A series of axially extending apertures are disposed in a circular array through the rotor holder in axial alignment with respective cuvettes in the rotor to permit light to be transmitted through the cuvettes as the rotor holder and cuvette rotor rotate between a stationary light source and photodetector. Additional apertures extend through the rotor holder near its periphery to permit light passage through the rotor holder for rotor and cuvette synchronization purposes. Movable rotor and cuvette synchronization detectors are positioned along the periphery of the rotor holder for generating signals which are used to synchronize the photometer output with a computer and to provide rotor speed control. Rapid deceleration of the rotor holder and rotor for sample mixing purposes is accomplished by braking means engaging the rotor holder drive shaft.

The Effect of Support Flexibility and Damping on the Synchronous Response of a Single-Mass Flexible Rotor

Abstract: Single mass flexible rotor in elastic bearings mounted on damped flexible supports, analyzing dynamic unbalance response and transient motions

Insulated coil for arrangement in a slot in the stator or rotor of an electric machine

Abstract: A coil positioned in the slot of a stator or rotor in an electric machine is formed of a bundle of conductors arranged close together and insulated from each other and from the slot. The conductor insulation consists of a layer of polymer and a tape of corona resistant insulating material running longitudinally of the conductor is adhered to the polymer layer. The tape surrounds the parts of the conductor facing the main insulation which surrounds the bundle of conductors and furthermore overlies at least those parts of the sides of the conductors which face the adjacent conductors which parts are situated nearest the sides facing the main insulation.

Centrifuge chuck for disposable, snap-in centrifuge rotor

Abstract: A chuck suitable for holding a disposable centrifuge rotor during centrifuging and requiring only minimum skill to place in position. Once the rotor is snapped into position on the chuck it is held by an elastomeric gripping member. The base of the rotor is designed to effect this holding. In removing the rotor, only a manual tipping action involving a modest horizontal force near the top of the rotor is required. The chuck is simple and inexpensive; and it does not require any great deal of technical skill to operate.

Logging-while-drilling tool

Abstract: A logging-while-drilling tool which is adapted to be positioned within the drill string of a well drilling apparatus. The tool has a turbinelike, signal-generating valve which opens and closes at a defined rate to generate a pressure wave signal in the drilling fluid which is representative of a measured downhole condition. The tool includes spring means to normally bias the rotor away from the stator of the valve. The force constant of the spring means is greater than the pressure drop across the rotor at low flow rates but is less than the pressure drop at the flow rate at which the tool begins operation. This allows the tool to maintain a large gap between the rotor and stator prior to operation of the tool or during periods of nonoperation thereby alleviating the problem of plugging and/or jamming of the valve. During normal operation the net force holding the rotor down, i.e., the force due to hydraulic pressure drop minus the spring force, is relatively small so that the rotor will ride up over and free itself from material which may become lodged in the gap, thus alleviating jamming of the valve. Also, structural features of the rotor aid in alleviating plugging of the valve.

Alternating current generator having a twin pm rotor which is adjustable in response to output voltage

Abstract: AN ALTERNATING CURRENT GENERATOR HAS A STATOR HAVING AN OUTPUT WINDING FOR PRODUCING AN OUTPUT VOLTAGE. A FIRST PERMANENT MAGNET ROTOR IS MOUNTED ON THE SHAFT OF THE GENERATOR FOR ROTATION THEREWITH. A SECOND PERMANENT MAGNET ROTOR IS MOUNTED COAXIALLY WITH THE FIRST PERMANENT MAGNET ROTOR ON THE SHAFT, THE SECOND ROTOR BEING ANGULARLY ADJUSTABLE WITH RESPECT TO THE SHAFT ABOUT THE COMMON AXIS. CONTROL MEANS ADJUST THE ANGULAR POSITION OF THE SECOND ROTOR, RELATIVE TO THE FRONT ROTOR IN RESPONSE TO CHANGES OF THE OUTPUT VOLTAGE.

Flexible Rotor Balancing by the Exact Point-Speed Influence Coefficient Method

Abstract: A test program was conducted to confirm experimentally the validity of the exact point-speed influence coefficient method for balancing rotating machinery, and to assess the practical aspects of applying the method to flexible rotors. Testing was performed with a machine having a 41-in. long, 126-lb rotor. The rotor was operated over a speed range encompassing three rotor-bearing system critical speeds: two “rigid-body” criticals and one flexural critical. Rotor damping at the flexural critical was very low due to the journal bearings being located at the nodal points of the shaft. The balancing method was evaluated for three different conditions of initial rotor unbalance. The method was found to be effective and practical. Safe passage through all the critical speeds was obtained after a reasonable number of balancing runs. Success of the balancing method was, in large part, due to the accuracy of the instrumentation system used to obtain phase-angle measurements during the balancing procedure.

Linear motor propulsion system

Abstract: A tracked vehicle propulsion system employs a plurality of linear synchronous motors, each having a thruster module, and all fixed in mutually spaced relation along a track. Trains of cars, mounted to ride along the track and each bearing a linear rotor having interdigitated magnetic poles, are propelled by successive thruster modules. Each thruster module is provided with a thruster control that is connected to establish interthruster logic and all modules are driven with three-phase stator drive signals from one or another of a group of thrust controllers. Velocity of this synchronous motor system is controlled open loop by direct control of stator drive signal frequency. Velocity changes are achieved by sweeping the stator frequency from synchronism with one frequency to synchronism with another frequency. The system operates a number of trains at a slow speed in a near bumper-to-bumper relation during a travel through a station and decelerates incoming trains for operation at station speed and position. Various methods of operation and control are provided, including, among others, a normal cyclic mode as the trains run from station to station and back, increasing or decreasing number of trains in service, manual or operator control of train movement, emergency stop, emergency start, and start for groups of trains.

Effect of Streamwise Vortices on Wake Properties Associated with Sound Generation

Abstract: T important aspects of the viscous wake leading to the generation of sound sources are: 1) unsteady twodimensional disturbances such as the Karman vortex street, and 2) unsteady forces generated by the passage of a rotor blade through the two-dimensional wake of a stator, or vice versa. The unsteady wake of an aircraft makes a significant contribution to the total noise during the landing approach, whereas the unsteady forces due to wake impingement on stator and rotor blades contribute significantly during takeoff and cruise. The latter effect, analyzed by Kemp and Sears, is responsible for about half of the pure-tone noise generated by turbomachines; the other half originates with the mutual interference between the rotor and stator flowfields. Wind-tunnel tests reported here show that the streamwise vortices shed from vortex generators near the trailing edges of a flat plate and an airfoil have a strong suppression effect on the formation of the Karman vortex street, and reduce the "effective" area of the velocity deficit in the wake, as seen by the following blade in a turbomachine. Both effects tend to suppress significantly the formation of sound sources.

Simulation for Design Purposes of Magnetic Fields in Turbogenerators with Symmetrical and Asymmetrical Rotors Part I-Model Development and Solution Technique

Abstract: A model the magnetic fields in turbo- generators with either symmetrical or asymmetrical rotor has been developed, and mathematically described and solutions obtained using the digital computer. The model was developed specifically for use in the design stage. It is applied to the entire cross-section of the generator and is applicable to a wide range of machine geometries.

Flywheel magneto ignition device with capacitor-thyristor ignition combined with generator

Abstract: A flywheel magneto ignition device with capacitor-thyristor ignition combined with generator comprises a first component group for producing an ignition effect and a second component group for generating current for lighting and/or battery charging purposes, the first component group comprising a rotor having mounted therein permanent magnets the pole of which are arranged to coact with coils containing at least one coil core and intended for the capacitor-thyristor-ignition circuit, and the second component group comprising a system of coils provided with iron cores and fixedly mounted in a rotating magnetic field from a body corotating with the rotor in the first component group, the rotor and the corotating body being mechanically connected together but with the respective magnetic fields shielded from each other.

Revolving display capsule

Abstract: A stationary display container has a plurality of shelves mounted on a central rotor therein and doors to gain access to the shelves. The container is temperature controlled by thermoelectric means including water cooling and fan circulated air.

Gas turbine starting and auxiliary turning mechanism

Abstract: A double input-single output power transmitting mechanism is utilized to accelerate the rotor of a gas turbine from standstill to initial operating speed, and to continue rotation of the rotor at slow speed during cooling after fuel shut-off. A friction clutch transmits both the starting torque and the slow speed turning torque to the turbine rotor.

Rotor structure for supercooled field winding

Abstract: A rotor for a cryogenic machine having a supercooled field winding including a hollow shaft rotatably supported on axle means and having an internal vacuum chamber; a field winding structure having radial interstices and axial interstices; a field winding structure compartment carried by the shaft for supporting the field winding structure; low thermal conductivity interconnection means interconnecting the compartment with the axle means; at least one heat exchanger means including a first member in thermal communication with the interconnection means at a discrete position along the interconnection means for removing heat from the interconnection means and a second member including a first conduit in thermal communication with the first member for removing heat from the first member using supercooled fluid flowing through the first conduit at a temperature higher than that of the supercooled field winding; and a convection trap associated with each heat exchanger means including a second conduit interconnected with the first conduit and having a portion having a course extending from larger to small radius to trap the warmer less dense fluid nearer the center of the rotor and the colder more dense fluid nearer the periphery of the rotor to prevent centrifugal convection in the centrifugal force field of the rotor.

Dynamoelectric machine cooled by a rotating heat pipe

Abstract: A dynamoelectric machine is described wherein heat generated within the rotor is removed utilizing a heat pipe rotating about the rotor shaft. Heat is absorbed from the rotor by vaporization of a portion of the refrigerant within a rectangular evaporator juxtaposed with the heat generating region of the rotor whereafter the vaporized refrigerant flows radially inward (due to centrifugal forces acting upon the higher density liquid refrigerant) to pass to a condenser coil secured to the rotor at a relatively cool location. Upon cooling to a liquid state in the condenser, the liquid refrigerant is forced radially outward along the condenser coil to return to the evaporator through a radially outer orifice. Preferably, the evaporator is situated within the rotor coils, e.g., at the center of the field pole winding of a synchronous machine, although the evaporator also could be positioned along any radially extending side of the rotor coil. Because refrigerant passes from the evaporator to the condenser and returns to the evaporator solely by centrifugal forces acting upon the closed cooling system, a separate refrigerant pump is not required to cool the motor.

Hingeless Helicopter Rotor Response with Nonuniform Inflow and Elastic Blade Bending

Abstract: A generalized harmonic balance theory for the steady-state, linear, response characteristics of a hingeless rotor in forward flight is presented and evaluated with the aid of recent experimental data. Comparisons of several approximate representations for the rotor blade revealed that the simple rigid hinged blade is inadequate except at very low advance ratios, or high flap frequencies. For typical values of flap frequency the first two elastic flap bending modes are required for accurate response predictions. Simplified models of the nonuniform induced inflow were derived, using momentum arid vbrtex theory, and found to be the most important factor in improving correlation with the data. An empirical inflow model was developed from the experimental data by obtaining an inverse solution of the present theory. This inflow model was found to be in reasonable agreement with the simple inflow theories for low advance ratios but revealed large unexpected variations in the induced inflow of the rotor for advance ratios near 0.8. a B b c CT d Cm e epc El J [L] m [M] [N] n p r, R U v'i v0 w

Composite ceramic turbine rotor

Abstract: A turbine rotor, comprising a hub or center section and an outer blade section integrally attached to the hub section, both sections being composed of a ceramic refractory material. The hub section possesses a high degree of mechanical strength, which normally requires that it have a specific gravity close to the theoretical specific gravity of the ceramic material used. The blade section of the rotor, which is permanently bonded to the hub, is composed of the same ceramic material as the hub section but of lower strength and lower density. The effect of the latter is relative ease of fabrication and reduced stresses on the hub section when attached thereto.

Design and fabrication of the Brayton rotating unit

Abstract: The Brayton rotating unit (BRU), operating on a gas bearing system, has been designed, fabricated, and demonstrated for use in a closed Brayton cycle space power conversion system. The BRU uses a binary mixture of xenon and helium (molecular weight, 83.8) as the cycle working fluid and bearing lubricating medium and was designed to produce from 2.25 to 10.5 kw sub e of 1200 Hz three-phase electrical power. The single-shaft rotating assembly operates at a design speed of 36,000 rpm and comprises a radial single-stage compressor, a four-pole Rice alternator rotor, and a radial inflow turbine. Four units, a dynamic simulator and three component research packages, were supplied to the NASA Lewis Research Center for performance testing and further development.

Air cooling of turbine blades

Abstract: A gas turbine engine is described, particularly the turbine rotor portion thereof and the bearing for journaling this rotor. Cooling air is directed along passageways extending through the bearing mounting and discharged into an entry chamber at the inner portion of the rotor. The rotor includes an annular plate spaced from a disc on which the rotor blades are mounted. The inner periphery of the plate defines the entrance of a passageway means for the flow of cooling air from the entry chamber to and through the blades to cool them. Cooling air as it is directed into the entry chamber at an angle such that its tangential vector approximates the peripheral speed of the cooling air passageway entrances. Further, vanes are provided on the blades to facilitate flow of cooling air through the rotor passageway means.

Dynamoelectric machine winding support

Abstract: A multi-phase stationary winding for an alternating current dynamo-electric machine, either of the type having a superconducting rotor winding or the air-gap winding iron-core type, is provided in which the conductors of the winding are helically disposed on a support structure so as to provide adequate mechanical support for the winding and reduce or obviate the problems of end winding support met in conventional alternating current machines of a similar nature.

Stepping motor exciter apparatus and method

Abstract: Disclosed is a salient pole stepping motor combined with high frequency current regulating chopper mode excitation apparatus connected to differentially excite at least two sets of electrical windings of the stepping motor in an excitation method wherein winding current is responsive to instantaneous rotor produced changes in electrical winding inductance.

Coaxial rotor yaw control

Abstract: A helicopter has coaxial counterrotating rotors having telescoping blade tip portions which are normally partially extended. Pilot operated means is provided for differentially extending and retracting the blade tip portions of the two rotors producing differential torque between rotors for yaw control. Pilot operated means is also provided for simultaneously retracting the tip portions of the blades of both rotors.

Method of making a rotor

Abstract: Laminations for a rotor are equipped with outwardly-projecting tabs; and those laminations are stacked so they are coaxial and so the outwardly-projecting tabs thereof are aligned to provide corresponding alignment of the conductor-receiving passages defined by those laminations. Welds are formed at the outer faces of the outwardly-projecting tabs to bond the laminations together; and then, after conductors have been diecast in the conductor-receiving passages, those outwardly-projecting tabs and the welds on the outer faces thereof are machined away to provide a smooth cylindrical surface for the rotor.