Showing papers on "Rotor (electric) published in 1982"

Torque compensated electrical motor

Abstract: An electric motor having a cage pivotally mounted at one end to a post interior a housing by a first bearing and at its other end by a second bearing between the exterior of the cage and the interior of the housing. A first stator is mounted to the interior of the cage and has an output shaft and first rotor interior thereto. A second rotor is mounted to the exterior of the cage and interior a second stator which is mounted interior the housing. The second stator is driven with a control signal which is a function of the measure reaction torque experienced by the first stator to produce a counter torque to balance the reaction torque. A consistency transmitter mounted on the output shaft produces torque on the first stator as a function of the consistency of the material in which it is rotated.

Turbine Rotor-Stator Interaction

Abstract: The aerodynamic interaction between the rotor and stator airfoils of a large scale axial turbine stage have been studied experimentally. The data included measurements of the time averaged and instantaneous surface pressures and surface thin film gage output on both the rotor and stator at midspan. The data also included measurement of the stator suction and pressure surface time averaged heat transfer at midspan. The data was acquired with rotor-stator axial gaps of 15 and 65 percent of axial chord. The upstream potential flow influence of the rotor on the stator was seen as well as the downstream potential flow and wake influences of the stator on the rotor. It was also seen that at the 15 percent axial gap, the stator heat-transfer coefficient was typically 25 percent higher than that at the 65 percent gap.

Theoretical and experimental power from large horizontal-axis wind turbines

Abstract: A method for calculating the output power from large horizontal-axis wind turbines is presented. Modifications to the airfoil characteristics and the momentum portion of classical blade element-momentum theory are given that improve correlation with measured data. Improvement is particularly evident at low tip-speed ratios where aerodynamic stall can occur as the blade experiences high angles of attack. Output power calculated using the modified theory is compared with measured data for several large wind turbines. These wind turbines range in size from the DOE/NASA 100 kW Mod-0 (38 m rotor diameter) to the 2000 kW Mod-1 (61 m rotor diameter). The calculated results are in good agreement with measured data from these machines.

Fixed pitch rotor performance of large horizontal axis wind turbines

Abstract: Experimental fixed pitch wind turbine performance data is presented for both the DOE/NASA Mod-0 and the Danish Gedser wind turbines. Furthermore, a method for calculating the output power from large fixed pitch wind turbines is presented. Modifications to classical blade element momentum theory are given that improve correlation with measured data. Improvement is particularly evident in high winds (low tip speed ratios) where aerodynamic stall occurs as the blade experiences high angles of attack.

Fractional-Frequency Rotor Motion Due to Nonsymmetric Clearance Effects

Abstract: Analysis based on the Jeffcott model is presented to explain 1/2 speed and 1/3 speed whirling motion occurring in rotors which are subject to periodic normal-loose or normal-tight radial stiffness variations. The normal-loose stiffness variation results due to bearing-clearance effects, while normal-tight stiffness variations result from rubbing over a portion of a rotor's orbit. The results demonstrate that 1/2 speed subharmonic motion can be explained as either a linear parametric-excitation phenomenon or as a stable nonlinear subharmonic motion. The 1/3 speed motion is shown to be possible due to the radial stiffness nonlinearity. A linear parametric-excitation analysis demonstrates that during a normal-tight rubbing condition, Coulomb damping significantly widens the potential range of unstable speeds.

Determination of Saturated Values of Rotating Machinery Incremental and Apparent Inductances by an Energy Perturbation Method

Abstract: Energy and winding current perturbations form the basis of a method for calculation of the saturated apparent and incremental inductances of rotating machinery as functions of rotor position and machine winding excitation currents. The method is totally general and utilizes numerical field calculation techniques in obtaining stored energy in the magnetic circuits of such machines. Thus, it can be applied to a wide class of machinery with practically any cross-sectional contours and number of windings. It can be used at any given set of excitations (any loads). This method was applied to the calculation of the apparent and incremental inductances of a 15 hp samarium cobalt permanent magnet synchronous machine. The necessary-numerical field soluitions were obtained by finite elements at both rated and no load conditions. The calculated inductances, at various rotor positions, were compared with those obtained during laboratory measurements and the agreement between calculated and measured values was consistently very good. The advantage of this method over the more traditional calculations of only the direct and quadrature axes inductances (or reactances, including transient and subtransient components) is that the entire n > n matrix of incremental inductances that truely govern the dynamic performance of an n winding machine can be determined regardless of the validity of a rotating d-q-o frame of reference.

Steady-state analysis of 3-phase cage motors with rotor-bar and end-ring faults

Abstract: An analysis is developed for 3-phase induction motors with any distribution and number of rotorbar and end-ring failures. The method is verified, using an inverted-geometry cage motor on which careful measurements of rotor-bar currents are made. The analysis is then used to investigate a rotor-bar fault on a 250 hp, 8-pole, 60 Hz motor.

Hybrid drive arrangement

Abstract: A hybrid drive arrangement for vehicles, in particular motor vehicles, has an electric machine (2) which can be fed from an electric energy store (7), if appropriate feeds back into it and is connected via a first switchable coupling (5) to a transmission (3) which drives at least one drive axle (6) of the vehicle and via a second switchable coupling (4) to a reciprocating piston internal combustion engine (1) which is connected in series to the electric machine. Here, the crankshaft of the reciprocating piston internal combustion engine is constructed without a flywheel and the flywheel mass which is required for compensating the unequal rotary force diagram of the reciprocating piston internal combustion engine (1) is essentially integrated into the rotor part (26) of the electric machine (2). According to the invention, the electric machine (2) also has an outer field component (27) which is held rotatably with respect to the fixed housing (35) and to the inner rotary component (26) which is mechanically connected to the couplings (4, 5), receives the field windings, and can be fixed to the fixed housing (35) by means of a brake device (28).

Fan unit for an internal combustion engine of automobile vehicle

Abstract: A fan unit for cooling an internal combustion engine comprising a fan impeller associated with a coaxial channel for guiding the air travelling through said impeller and an electric driving motor of DC type. The channel is fixed to the ends of the blades of the impeller and rotates with the impeller and itself constitutes the rotor of the electric motor whose stator coaxially surrounds at least a part of the channel. The stator is rigid with a fixed shaft around which the impeller rotates. This fan unit has a high permeability when inoperative so that it is particularly adapted for use in an automobile vehicle.

Method for monitoring an oil well pumping unit

Abstract: Instantaneous speeds of revolution for a beam pumping unit prime mover rotor, determined for all or a predetermined part of the pumping unit reciprocation cycle, are applied to compute one or more parameters of pumping unit performance, which are compared to predetermined values for such parameters to detect the existance of cause (such as pump-off, mechanical malfunction, electrical operating inefficiency or pumping unit imbalance) for correction of pumping unit operation, which is done if indicated by the comparison.

Motion responsive wind turbine tower damping

Abstract: An accelerometer (1) disposed on the support tower (12) of a wind turbine electric generating system in the vicinity of the rotor (10, 16) thereof provides a signal (1) indicative of acceleration of the tower in the direction of the rotor rotational axis. The signal (2) is passed through a band-pass filter (4) for summation (9) with a torque/power controlled (100) blade pitch angle reference rate signal (98), the integral (104) of which provides a blade pitch angle reference signal (40) to control the pitch angle of the rotor blades (10) through a pitch change mechanism (38), thereby to provide additional, positive aerodynamic damping to the tower while modulating blade angle for constant torque/power in response to wind turbulence.

Rotor blade for a rotary machine

Abstract: A rotor blade 14 having a spar 138 and shell 134 is disclosed. Various construction details are developed for efficiently transferring rotational loads on the rotor blade to the root section 28 of the spar. The spar has a projection 139 over which extends a portion 100 of the shell and a platform 36 of the rotor blade.

An Investigation of Axial Compressor Rotor Aerodynamics

Abstract: The detailed nature of the three-dimensional flow over the blading, and in the wake, of an isolated compressor rotor has been studied experimentally in a large scale rotating rig. A variety of flow properties were measured including (1) blade profile and endwall surface flow visualization. (2) radial-circumferential arrays of pneumatic wake data acquired in the rotating frame and (3) full-span blade pressure distribution data. 23 refs.

Aerodynamic Loads and Performance of the Darrieus Rotor

Abstract: The double-multiple-streamtube model was used for determining the aerodynamic blade loads and roto performance on the Darrieus vertical-axis wind turbine with curved blades. This analytical model i capable of predicting the difference in the induced velocities at the upstream and downstream passes. The upwind and downwind interference factors are calculated by a double iteration, one for each half of the rotor and vertical variations in the freestream velocity are accounted for. Under local aerodynamic conditions a closed-form analytical solution is obtained for two functions, one for the upwind and one for the downwind hal of the turbine. Thus the local aerodynamic loads on the blade and the rotor performance are calculated more accurately than by other streamtube methods. Comparison of the analytical results obtained with the doublemultiple-streamtube model and the available field test data for the Sandia 17-m machine shows good agreement. This method can therefore be used for generating a suitable aerodynamic-load model for structural-design analysis of the Darrieus rotor.

Equipment for storage of energy under kinetic form and recovery thereof in electric form and method of using such equipment

Abstract: An uninterruptible electric power source comprising a rotor and a stator with the stator having a magnetically suspended flywheel with magnet rings for radial centering, a double electromagnet in a servoloop for restoring equilibrium including a rate sensor and lift-off logic in the servoloop encased in an evacuated vacuum enclosure. Variation in the structure of elements including the enclosure are described.

Turbojet with contrarotating wheels

Abstract: A turbojet having a multistage axial compressor with contrarotating blade wheels fitted on inner and outer contrarotating rotors driven in opposite directions by respective turbine wheels. Each blade wheel (105) of the outer compressor rotor is associated with a rotating shell (86, 81, 82) having relatively few thick spokes for transmitting the drive from the turbine wheel, thereby leaving the blades to transmit aerodynamically induced forces only.

Lock cylinder with integrated electromagnetic locking system

Abstract: A magnetic bolt has a movable and electromagnetically operable locking member which, in conjunction with a locking part arranged on the rotor of a lock cylinder, blocks or releases the rotor, independently of the mechanical tumblers depending on whether the locking member is located in a free-running slot or a locking notch of the locking part. The magnetic bolt is arranged in a recess in the lock cylinder stator and provides an electromagnetic locking operation by energizing a field coil.

Infinite conical well: An analytic model for quantum mechanical hindered rotors

Abstract: The rotational quantum mechanics of a new analytic model for a hindered rotor is presented, and rotational-state distributions of the hindered rotor are given in terms of unhindered rotor states.

Joystick controller using magnetosensitive elements with bias magnets

Abstract: A joystick controller of the electrically non-contact type is provided with a pair of magnetosensitive elements having a magnetresistive effect. The magnetosensitive elements are placed fixedly on a stator member in a given relation at right angles to detect the rotary motion of a permanent magnet embedded in a rotor member movably supported by the stator member. Each of the magnetosensitive elements is supplied by a constant bias magnetic field generated by added magnets on the stator member to improve the sensing characteristics of the controller. In addition, a spring sheet member is assembled between surfaces of the rotor and stator members to afford appropriate feeling and handling for operation of the lever.

Hand held device with built-in motor

Abstract: A hand held device with built-in motor for rotational drive of small tools. The hand held device includes an outer housing consisting of a larger diameter rear part which contains an electric driving motor, an intermediate part of small diameter which contains motion transmitting means, and a front part in which is mounted a holder for the tool to be driven. The electric driving motor is a brushless motor having a rotor encapsulated in a sealed insulating enclosure and includes permanent magnets covered with a layer of conducting metal and a stator made up of multi-phase winding coils embedded in a molded plastic material. The motion transmission means consists of non-contacting magnetic coupling means.

Brushless ultra-efficient regenerative servomechanism

Abstract: A servomechanism regeneratively controls motion by a brushless coreless axial-field motor, exerting torque thru its permanent-magnet disk rotor, resulting from synchronized polyphase sinusoidal stator currents, controlled by a switching controller responsive to input commands and to Hall-effect transducer signals that vary sinusoidally with rotor angle and respectively correspond to stator phases. The controller operates with a dc power source and sink. Its signal processors derive from the transducer signals instantaneous magnitudes and polarities thereof and continuous lagless speed feedback. The instantaneous magnitudes are multiplied by a torque amplitude signal to provide respective synchronized amplitude control signals. Current transformers having primary windings in series with power switching transistors provide current feedback pulses with amplitude proportional to instaneous current in associated stator windings. Pulse control means initiate bi-phase pulses having restricted duty-cycle, and dictate pulse duration by comparing each current feedback pulse with the associated synchronized amplitude control signal. Switching logic responsive to the bi-phase pulses, to forward and reverse drive and brake commands, and to said polarities, accordingly controls selection and duty-cycle of said power switching transistors which, cooperative with free-wheeling diodes and inductors, effect controlled alternating stator currents. Various signal interface means process the input commands with feedback derived from the transducer signals, such as speed, direction of rotation, and interpolated digital position, to provide said torque amplitude signal, and variously, said drive and brake commands; so the motor and controller constitute a complete servomechanism, that provides precise speed and position control with regenerative reversing and braking, ultra-high efficiency, and fast dynamic response.

High torque robot motor

Abstract: An electric motor comprised of laminated, coaxial, annular, inner and outer stators with an annular rotor coaxially positioned between the stators and with coils wrapped about corresponding, angularly spaced apart pole pieces of the inner and outer stators to generate a magnetic flux path which passes radially outward and inward through the rotor from the inner and outer stator pole pieces.

Rotor system for horizontal axis wind turbines

Abstract: A rotor system for horizontal-axis wind turbines is provided having compound coning and a sweep angle to improve the rotor system's yaw responsiveness and stability and to reduce vibration and stress. To further improve wind turbine performance and rotor durability blades with the load-bearing function and airfoil function separated are disclosed and are particularly useful in rotor systems having compound coning or compound coning and sweepback. The load-bearing function and support function of the rotor hub are separated to improve rotor system durability and to provide a rotor hub for use with a pitch change mechanism for altering the pitch of rotor system blades.

Wind turbine rotor control system

Abstract: In a pitch control system for a wind turbine, a mechanical control system changes pitch angle of the rotor blades collectively in response to blade pitch moment. The control system is designed to be used with a downwind constant speed two-bladed horizontal axis teetering hub wind turbine. Pitch placement controls torque for a synchronous alternator connected to the electrical power grid. The pitch control system is manually lockable from the ground in run or shutdown modes. An automatic shutdown mode provides fullfeathering for protection from large amplitude vibrations or loss of the electrical grid.

Rotary converter machine for direct transfer of electric energy by flux linkage between windings on a stator pack

Abstract: A rotary converter machine which includes a stator with three-phase primary, and secondary windings, and a rotor mounted within the stator which includes a damping winding. The primary and secondary stator windings are arranged on a common stator pack and located in continuous stator slots, both windings extending over the whole axial length of the common stator pack. The converter machine provides a direct transfer of the electrical energy by flux linkage between the two windings. The rotor is driven by the rotating magnetic field either asynchronously, if a drum rotor is provided, or synchronously, if a salient-pole rotor is provided.

Electronically commutated motor, method of operating such, control circuit, laundry machine and drive therefor

Abstract: An electronically commutated motor for energization by DC in both a high speed mode and a low speed mode at a current not significantly greater than a preselected level. The motor stator has a plurality of winding stages each with a plurality of winding turns only a first portion of which is commutated in a first sequence in a high speed mode and a predeterminately greater portion of which is commutated in a second sequence different from the first when the motor is energized in the low speed mode. A permanent magnet rotor is rotatably driven in one direction in the high speed mode so as to develop a first torque at the preselected current level when only the first portion of the winding turns of the winding stages are commutated in the first preselected sequence. In response to commutation in the second sequence of the predeterminately greater portion of the winding turns the rotor is rotatably driven alternately in opposite directions in the low speed mode so as to develop a second torque predeterminately greater than the first torque at a current not significantly greater than the preselected level. A method of operating such motor, a control circuit therefor and the use of such a motor in laundry machines and drives therefor are also disclosed.

Influence of unsteady aerodynamics on hingeless rotor ground resonance

Abstract: Calculations of the model frequency and damping for a hingeless rotor on a gimballed support in hover are compared with measured results for two configurations (differing in blade flap stiffness). Good correlation is obtaned when an inflow dynamics model is used to account for the influence of the unsteady aerodynamics. The effect of the unsteady aerodynamics is significant for this rotor system. The inflow dynamics model introduces additional states corresponding to perturbations of the wake-induced velocity at the rotor disk. The calculations confirm the experimental observation that the inflow mode introduced by these additional states is measurable for one configuration but not for the other.