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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 379 records · Page 21

All sources NASA NTRS DOE OSTI

NASA NTRS1978

A comparison of motor submodels in the optimal control model

Properties of several structural variations in the neuromotor interface portion of the optimal control model (OCM) are investigated. For example, it is known that commanding control-rate introduces an open-loop pole at S=O and will generate low frequency phase and magnitude characteristics similar to experimental data. However, this gives rise to unusually high sensitivities with respect to motor and sensor noise-ratios, thereby reducing the models' predictive capabilities. Relationships for different motor submodels are discussed to show sources of these sensitivities. The models investigated include both pseudo motor-noise and actual (system driving) motor-noise characterizations. The effects of explicit proprioceptive feedback in the OCM is also examined. To show graphically the effects of each submodel on system outputs, sensitivity studies are included, and compared to data obtained from other tests.

Lancraft, R. E.↗

DOE OSTI2024

Tutorial - Electric Motor and Integrated Traction Drive Thermal Management

The share of vehicles with fully electric propulsion systems is constantly increasing, and so is their traction drive power. The continuous push to increase power of electric vehicle (EV) traction drives necessitates their efficient cooling to prevent damage to temperature sensitive components of the drive system and achieving higher power outputs in a smaller footprint. With increasing power and power density of electric traction drives, their thermal management is becoming increasingly challenging. This tutorial will provide an overview of thermal management approaches for electric motors and power electronics in EV applications. It will review examples of current industry solutions for power-dense electric motor cooling, power electronics (inverter) cooling, their integration concepts and thermal management system solutions. We'll look at the advantages and challenges of power electronics integration into a single traction drive unit and respective thermal management system concepts. We'll talk about barriers to implementation of a unified thermal management system. The tutorial will also review key aspects of thermal management system design: modeling and simulation using FEA and CFD tools, experimental characterization, and general workflow for thermal management system evaluation.

ADVANCED PROPULSION SYSTEMS,DIRECT ENERGY CONVERSI↗

DOE OSTI2022

Fully Integrated High Speed Megawatt Class Motor and High Frequency Variable Speed Drive System

This project involved developing a fully integrated high speed megawatt class motor and high frequency variable speed drive system that serve as a commercially viable and technically sound methodology for high speed industrial system applications. The project team organizations consist of Clemson University and TECO Westinghouse Motor Company (TWMC) formed an academic and industrial collaboration that combines the design, analysis, manufacturing and testing experience required for a large research project of this magnitude. The project resulted in an integrated high speed megawatt class medium voltage motor drive system that is at a TRL 6 with a clear path for commercialization. The fully integrated prototype system has been manufactured by TWMC in its Round Rock, Texas facility and tested at full power on a dynamometer at the Clemson University’s eGRID Center in North Charleston, South Carolina.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRS1967

Circuit increases capability of hysteresis synchronous motor

Frequency and phase detector circuit enables a hysteresis synchronous motor to drive a load of given torque value at a precise speed determined by a stable reference. This technique permits driving larger torque loads with smaller motors and lower power drain.

Markowitz, I. N.↗

NASA NTRS2014

Lightweight, Efficient Power Converters for Advanced Turboelectric Aircraft Propulsion Systems

NASA is investigating advanced turboelectric aircraft propulsion systems that use superconducting motors to drive multiple distributed turbofans. Conventional electric motors are too large and heavy to be practical for this application; therefore, superconducting motors are required. In order to improve aircraft maneuverability, variable-speed power converters are required to throttle power to the turbofans. The low operating temperature and the need for lightweight components that place a minimum of additional heat load on the refrigeration system open the possibility of incorporating extremely efficient cryogenic power conversion technology. This Phase II project is developing critical components required to meet these goals.

Hennessy, Michael J.↗

NASA NTRS1978

Applicability of the Remote Mobile Emplacement Package (RMEP) design as a mobility aid for proposed post-84 Mars missions, phase O

The results of study to determine the applicability of the Remote Mobile Emplacement Package (RMEP) design concept as a mobility aid for the proposed post-'84 Mars missions are presented. The RMEP wheel and mobility subsystem parameters: wheel tire size, weight, stowed volume, and environmental effects; obstacle negotiation; reliability and wear; motor and drive train; and electrical power demand were reviewed. Results indicated that: (1) the basic RMEP wheel design would be satisfactory, with additional attention to heating, side loading, tread wear and ultraviolet radiation protection; (2) motor and drive train power requirements on Mars would be less than on Earth; and (3) the mobility electrical power requirements would be small enough to offer the option of operating the Mars mini rover untethered. Payload power required for certain sampling functions would preclude the use of battery power for these missions. Hazard avoidance and reverse direction maneuvers are discussed. Limited examination of vehicle payload integration and thermal design was made, pending establishment of a baseline vehicle/payload design.

Source record↗

NASA NTRS2021

NASA Ames Research Center Unitary Plan Wind Tunnel Fall 2018 Outage - Motor 1 Activity: Stator Shift

The Unitary Plan Wind Tunnel consists of the 11 x 11- Foot Transonic Wind Tunnel and the 9 x 7 foot Supersonic Wind Tunnel. The four 65,000hp electric motors that drive the wind tunnel compressors require periodic maintenance. In order to inspect the motors without the removal of drive shaft components, the stator must be shifted away from the motor. This process is referred to as "Stator Shift". Video is mp4 formatted with runtime of 2 mins 54 secs.

Wind Tunnel↗

NASA NTRS2018

Electric Motor Noise for Small Quadcopters: Part I - Acoustic Measurements

There is increased interest in using electric motors to drive propulsors across a range of small air vehicle classes. Applications include both vertical lift and conventional takeoff and landing systems for Small Unmanned Aircraft Systems. Mission profiles call for integrating these systems into urban airspaces exposing populated areas to new noise sources. In addition to the propulsor noise from rotors and propellers, electric motors are expected to contribute to the overall sound levels and possibly human annoyance. This work presents acoustic measurements of electric motors used for small quadcopters to characterize the sound and identify sources with and without a propeller. Free field microphone measurements were used to determine directivity and a phased microphone array was used to identify sound sources. A companion paper (Part II – Source Characteristics and Prediction) compares the far field results with current probe measurements of the signal driving the motor, the structural response of the motor case, and describes prediction methods of electric motor noise.

Aircraft Noise↗

NASA NTRS2018

Electric Motor Noise from Small Quadcopters: Part 1 - Acoustic Measurements

There is increased interest in using electric motors to drive propulsors across a range of small air vehicle classes. Applications include both vertical lift and conventional takeoff and landing systems for Small Unmanned Aircraft Systems. Mission profiles call for integrating these systems into urban airspaces exposing populated areas to new noise sources. In addition to the propulsor noise from rotors and propellers, electric motors are expected to contribute to the overall sound levels and possibly human annoyance. This work presents acoustic measurements of electric motors used for small quadcopters to characterize the sound and identify sources with and without a propeller. Free field microphone measurements were used to determine directivity and a phased microphone array was used to identify sound sources. A companion paper (Part II - Source Characteristics and Prediction) compares the far field results with current probe measurements of the signal driving the motor, the structural response of the motor case, and describes prediction methods of electric motor noise.

Electric Propulsion↗

NASA NTRS1980

Centrifugal reciprocating compressor

Efficient compressor uses centrifugal force to compress gas. System incorporates two coupled dc motors, each driving separate centrifugal reciprocating-compressor assembly. Motors are synchronized to accelerate and decelerate alternately.

High, W. H.↗

NASA NTRS2013

Acoustic Mechanical Feedthroughs

Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be feasible. A variety of designs that have been designed, fabricated and tested will be presented

piezoelectric devices↗

NASA NTRS2004

Sensory-Feedback Exoskeletal Arm Controller

An electromechanical exoskeletal arm apparatus has been designed for use in controlling a remote robotic manipulator arm. The apparatus, called a force-feedback exoskeleton arm master (F-EAM) is comfortable to wear and easy to don and doff. It provides control signals from the wearer s arm to a robot arm or a computer simulator (e.g., a virtual-reality system); it also provides force and torque feedback from sensors on the robot arm or from the computer simulator to the wearer s arm. The F-EAM enables the wearer to make the robot arm gently touch objects and finely manipulate them without exerting excessive forces. The F-EAM features a lightweight design in which the motors and gear heads that generate force and torque feedback are made smaller than they ordinarily would be: this is achieved by driving the motors to power levels greater than would ordinarily be used in order to obtain higher torques, and by providing active liquid cooling of the motors to prevent overheating at the high drive levels. The F-EAM (see figure) includes an assembly that resembles a backpack and is worn like a backpack, plus an exoskeletal arm mechanism. The FEAM has five degrees of freedom (DOFs) that correspond to those of the human arm: 1. The first DOF is that of the side-to-side rotation of the upper arm about the shoulder (rotation about axis 1). The reflected torque for this DOF is provided by motor 1 via drum 1 and a planar four-bar linkage. 2. The second DOF is that of the up-and-down rotation of the arm about the shoulder. The reflected torque for this DOF is provided by motor 2 via drum 2. 3. The third DOF is that of twisting of the upper arm about its longitudinal axis. This DOF is implemented in a cable remote-center mechanism (CRCM). The reflected torque for this DOF is provided by motor 3, which drives the upper-arm cuff and the mechanism below it. A bladder inflatable by gas or liquid is placed between the cuff and the wearer s upper arm to compensate for misalignment between the exoskeletal mechanism and the shoulder. 4. The fourth DOF is that of flexion and extension of the elbow. The reflected torque for this DOF is provided by motor 4 and drum 4, which are mounted on a bracket that can slide longitudinally by a pin-and-slot engagement with the upper-arm cuff to compensate for slight variations in the position of the kinematic center of the elbow. Attached to drum 4 is an adapter plate to which is attached a CRCM for the lower arm. 5. The lower-arm CRCM implements the fifth DOF, which is the twist of the forearm about its longitudinal axis. Motor 5 provides the reflected torque for this DOF by driving the lower-arm cuff. A rod transmits twist and torsion between the lower-arm cuff and the hand cuff. With this system, the motion of the wearer s joints and the reflected torques applied to these joints can be measured and controlled in a relatively simple manner. This is because the anthropomorphic design of the mechanism imitates the kinematics of the human arm, eliminating the need for kinematic conversion of joint-torque and joint-angle data.

An, Bin↗

NASA NTRSDate not supplied

Surface Vibration Measurement and Analysis for UAM/UAS Electric Motor Noise

Urban Air Mobility vehicles are an emerging class of vertical lift vehicles using electric motors to drive multiple rotors for lift. The outrunner electric motors that are commonly used, may be capable of generating noise that could contribute to the vehicle’s overall noise profile and could generate cabin noise. Understanding and predicting the noise requires more knowledge of the rotor vibrations and eventually a model to predict the frequencies of those vibrations. This work presents a measurement of the rotor vibrations of two different small-scale motors. Two techniques to measure the surface vibration were used. The displacement spectra are compared with acoustic measurements. A finite element analysis model is used to predict the rotor resonance frequencies. The predicted frequencies are in fair agreement with the experimentally observed vibration frequencies, but requires further work to understand discrepancies.

Electric Motor Noise↗

NASA NTRS2010

In-Situ Focusing Inside a Thermal Vacuum Chamber

Traditionally, infrared (IR) space instruments have been focused by iterating with a number of different thickness shim rings in a thermal vacuum chamber until the focus meets requirements. This has required a number of thermal cycles that are very expensive as they tie up many integration and test (I&T)/ environmental technicians/engi neers work ing three shifts for weeks. Rather than creating a test shim for each iteration, this innovation replaces the test shim and can focus the instrument while in the thermal vacuum chamber. The focus tool consists of three small, piezo-actuated motors that drive two sets of mechanical interface flanges between the instrument optics and the focal- plane assembly, and three optical-displacement metrology sensors that can be read from outside the thermal vacuum chamber. The motors are used to drive the focal planes to different focal distances and acquire images, from which it is possible to determine the best focus. At the best focus position, the three optical displacement metrology sensors are used to determine the shim thickness needed. After the instrument leaves the thermal vacuum chamber, the focus tool is replaced with the precision-ground shim ring. The focus tool consists of two sets of collars, one that mounts to the backside of the interface flange of the instrument optics, and one that mounts to the backside of the interface flange of the focal plane modules. The collars on the instrument optics side have the three small piezo-actuated motors and the three optical displacement metrology systems. Before the instrument is focused, there is no shim ring in place and, therefore, no fasteners holding the focal plane modules to the cameras. Two focus tooling collars are held together by three strong springs. The Orbiting Carbon Observatory (OCO) mission spectrometer was focused this way (see figure). The motor described here had to be moved five times to reach an acceptable focus, all during the same thermal cycle, which was verified using pupil slicing techniques. A focus accuracy of .20.100 microns was achieved.

Liebe, Carl Christian↗

DOE OSTI2022

Rare Earth Permanent Magnets: Supply Chain Deep Dive Assessment

The report “America’s Strategy to Secure the Supply Chain for a Robust Clean Energy Transition” lays out the challenges and opportunities faced by the United States in the energy supply chain as well as the federal government plans to address these challenges and opportunities. It is accompanied by several issue-specific deep dive assessments, including this one, in response to Executive Order 14017 “America’s Supply Chains,” which directs the Secretary of Energy to submit a report on supply chains for the energy sector industrial base. The Executive Order is helping the federal government to build more secure and diverse U.S. supply chains, including energy supply chains. This report focuses on the supply chain for rare earth permanent magnets, specifically sintered neodymiumiron-boron (NdFeB) magnets, used in clean energy technologies. Sintered NdFeB magnets are the strongest magnets commercially available and provide a host of benefits to wide-ranging applications in consumer and industrial electronics, especially in advanced motor and drive systems. Within the Energy Sector Industrial Base, and clean energy in particular, NdFeB magnets are key intermediate components of permanent magnet synchronous (direct drive) generators in wind turbines (especially for offshore turbines) and electric synchronous traction motors for propulsion systems in battery and hybrid electric vehicles.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

NASA NTRS1977

Electro-optically-indexed microwave switch

Mechanical parts used in conventional switches to index stepper motor that drives switch elements are replaced by optoelectronic indexing device that controls magnetic-detent motor. Unit eliminates major source of wear and maintains detent accuracy longer. Design of device achieves reduction of insertion loss, crosstalk, and wave guide reflections when receiving and transmitting.

Neff, D. E.↗

NASA NTRS1982

Modification of Altitude Wind Tunnel for Icing and Propulsion Research Study, Part B

This report describes the results of an engineering study conducted for NASA-Lewis Research Center on Modifications to the Altitude Wind Tunnel (AWT) for Icing and Propulsion Research by DSW Engineering Corporation, Orlando, Florida and DSMA International Inc., Toronto, Canada. The engineering study referred to as study 'Part B' has been carried out under authorization of NASA Contract NAS 3-22933 (Ref. 1). The scope of work defined in the Statement of Work 3-169855 (Ref. 2) Revised 2/20/81 was discussed in detail with NASA on October 2, 1981 and covers the following areas: - Fan and Fan Housing. This includes assessment of circuit loss analyses, fan aerodynamics and mechanical conceptual design of variable and fixed pitch fans considering fixed and variable inlet guide vanes. - Fan Drive Systems - considering fixed and variable speed drives with continuous rating of 30,000 HP with overload capability of 45,000. The drive shaft between the motor and fan is to be considered and also the existing foundations for the main drive motor. - 20 ft.Test Section Arrangement - having slotted wall configurations suitable for testing at transonic velocities, with various model support systems required for the anticipated models and tests. A model handling concept aimed for high productivity testing and means for quick access to the model in the test section between test runs. - 45 ft. Test Section - feasible and practical approach for model installation and removal.

Leonard, H. Wayne↗

NASA NTRS2004

Prototype Motor Controllers Demonstrated for the James Webb Space Telescope Cryogenic Environment

NASA is in the process of designing the James Webb Space Telescope. This telescope will investigate images of objects in deep space (stars, galaxies, etc.) by using light in the infrared region of the light spectrum. To make such observations, the telescope must have light sensors that operate at very cold temperatures, near absolute zero. To achieve this low-temperature tolerance, designers must place the light sensors behind a Sun shield that will prevent sunlight, and its heat, from reaching the sensors. In this cold region inside the telescope, electric motors and some motor controls must operate at temperatures near 40 K (40 degrees above absolute zero). These motors will be used to position light filters needed by the telescope. There are motors that operate at the low temperatures, but there is little technology for low-temperature motor-control electronics. The drawing shows how the motors and their controls are positioned behind the Sun shield. Simplified version of the layout of the motor and control electronics that are located, as dictated by mission requirements, in the cold zone of the James Webb Space Telescope. A Sun shield provides protection and isolation of these electronics from the heat of the rays of the sun. Room temperature compoenets (control computer, motor select command, motor phase drive, power supply, parallel to serial, and sun shield) as well as 40-kelvin components (motor select, serial to parallel, and motors) are shown. The Low Temperature Electronics Group at the NASA Glenn Research Center has been working to develop motor control electronics that will operate at a temperature of 40 K. The group conducted tests to determine which electronic components will operate at such very low temperatures. Then, components that were determined to operate successfully at the low temperatures were used to design low-temperature motor-controller circuits. A prototype motor controller circuit was built, evaluated, and demonstrated to operate at 70 K. Next, Glenn researchers plan to determine circuit performance at much colder temperatures--down to 40 K. This low-temperature program was supported by the James Webb Space Telescope Electrical Systems Design Group at the NASA Goddard Space Flight Center and by the NASA Electronic Parts and Packaging Program at NASA Headquarters and the Jet Propulsion Laboratory.

Patterson, Richard L.↗