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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 109 records · Page 6

All sources NASA NTRS DOE OSTI

NASA NTRS1975

Spacecraft high-voltage power supply construction

The design techniques, circuit components, fabrication techniques, and past experience used in successful high-voltage power supplies for spacecraft flight systems are described. A discussion of the basic physics of electrical discharges in gases is included and a design rationale for the prevention of electrical discharges is provided. Also included are typical examples of proven spacecraft high-voltage power supplies with typical specifications for design, fabrication, and testing.

Sutton, J. F.↗

NASA NTRS1977

Pulse-width-modulated high-current power supply

Power supply achieves efficiency rating of approximately 80 percent at rated maximum output current. Protection circuitry prevents logic/memory loads from losing stored data if supply protection circuit initiates power shut down; prevents damage caused by overtemperature condition; protects logic/memory load from undervoltage to overvoltage conditions. Warning signal indicates power shutdown.

Messano, E. A.↗

NASA NTRS1977

Thermal control of power supplies with electronic packaging techniques

The integration of low-cost commercial heat pipes in the design of a NASA candidate standard modular power supply with a 350 watt output resulted in a 44% weight reduction. Part temperatures were also appreciably reduced, increasing the environmental capability of the unit. A complete 350- watt modular power converter was built and tested to evaluate thermal performance of the redesigned supply.

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NASA NTRS1976

Arc discharge supply component protection circuitry

In a mercury-bombardment ion engine, the discharge supply is a high-current low-voltage one that maintains an arc or discharge inside the engine. In a 30-cm engine the supply provides up to 45 volts at about 13 amperes and is referenced at approximately 1100 volts above ground. Due to the engine discharge characteristics, a very slow feedback control loop is required. A high-speed current limit must be used to protect the components in the power conditioner, a pulse-width-modulated bridge inverter. A high-speed cycle-by-cycle current-limit circuit which allows the inverter to continue running in an overcurrent condition is used to protect it. The high-speed current sensing allows the inverter to be turned off each half cycle before the current in the primary of the inverter exceeds a safe level. This permits the inverter to continue to provide current into a discharge or a fault condition, until the feedback control system can actively control the current.

Ahrens, A. F.↗

NASA NTRS1978

Computerized power supply analysis: State equation generation and terminal models

To aid engineers that design power supply systems two analysis tools that can be used with the state equation analysis package were developed. These tools include integration routines that start with the description of a power supply in state equation form and yield analytical results. The first tool uses a computer program that works with the SUPER SCEPTRE circuit analysis program and prints the state equation for an electrical network. The state equations developed automatically by the computer program are used to develop an algorithm for reducing the number of state variables required to describe an electrical network. In this way a second tool is obtained in which the order of the network is reduced and a simpler terminal model is obtained.

Garrett, S. J.↗

NASA NTRS1978

Coal supply for California

The potential sources and qualities of coals available for major utility and industrial consumers in California are examined and analyzed with respect to those factors that would affect the reliability of supplies. Other considerations, such as the requirements and assurances needed by the coal producers to enter into long-term contracts and dedicate large reserves of coal to these contracts are also discussed. Present and potential future mining contraints on coal mine operators are identified and analyzed with respect to their effect on availability of supply.

Yancik, J. J.↗

NASA NTRS1979

Demand and supply of hydrogen as chemical feedstock in USA

Projections are made for the demand and supply of hydrogen as chemical feedstock in USA. Industrial sectors considered are petroleum refining, ammonia synthesis, methanol production, isocyanate manufacture, edible oil processing, coal liquefaction, fuel cell electricity generation, and direct iron reduction. Presently, almost all the hydrogen required is produced by reforming of natural gas or petroleum fractions. Specific needs and emphases are recommended for future research and development to produce hydrogen from other sources to meet the requirements of these industrial sectors. The data and the recommendations summarized in this paper are based on the Workshop 'Supply and Demand of Hydrogen as Chemical Feedstock' held at the University of Houston on December 12-14, 1977.

Huang, C. J.↗

NASA NTRS1979

A study of industrial hydrogen and syngas supply systems

The potential and incentives required for supplying hydrogen and syngas feedstocks to the U.S. chemical industry from coal gasification systems were evaluated. Future hydrogen and syngas demand for chemical manufacture was estimated by geographic area and projected economics for hydrogen and syngas manufacture was estimated with geographic area of manufacture and plant size as parameters. Natural gas, oil and coal feedstocks were considered. Problem areas presently affecting the commercial feasibility of coal gasification discussed include the impact of potential process improvements, factors involved in financing coal gasification plants, regulatory barriers affecting coal gasification, coal mining/transportation, air quality regulations, and competitive feedstock pricing barriers. The potential for making coal gasification the least costly H2 and syngas supply option. Options to stimulate coal gasification system development are discussed.

Amos, W. J.↗

NASA NTRS1980

DC-to-DC power supply for light aircraft flight testing

The power supply unit was developed to serve as the power source for a loran-C receiver. The power supply can be connected directly to the aircraft's electrical system, and is compatible with either 14 or 28 volt electrical systems. Design specifications are presented for the unit along with a description of the circuit design.

Yost, S. R.↗

NASA NTRS1981

Conceptual design and analysis of orbital cryogenic liquid storage and supply systems

A wide variety of orbital cryogenic liquid storage and supply systems are defined in NASA and DOD long-range plans. These systems include small cooling applications, large chemical and electrical orbit transfer vehicles and supply tankers. All have the common requirements of low-g fluid management to accomplish gas-free liquid expulsion and efficient thermal control to manage heat leak and tank pressure. A preliminary design study was performed to evaluate tanks ranging from 0.6 to 37.4 cu m (22 to 1320 cu ft). Liquids of interest were hydrogen, oxygen, methane, argon and helium. Conceptual designs were generated for each tank system and fluid dynamic, thermal and structural analyses were performed for Shuttle compatible operations. Design trades considered the paradox of conservative support structure and minimum thermal input. Orbital performance and weight data were developed, and a technology evaluation was completed.

Eberhardt, R. N.↗

NASA NTRS1982

ORION downconverter and power supply

The receiver subsystem supplies the front end assembly (downconverter) and power supply for the ORION Mobile Station. These assemblies are designed to withstand severe environmental conditions. The mechanical, electronic, environmental and maintenance design considerations encountered during the design phase of this project are discussed. The two channel S/X downconverter has a 400 MHz bandwidth channel. Phase stability of 2 and 7 deg at S- and X-bands, respectively, is achieved with a temperature stabilized first local oscillator.

Nishimura, H. G.↗

NASA NTRS1982

Thematic mapper flight model preshipment review data package. Volume 4: Appendix. Part C: Power supply data

The acceptance test data package for the thematic mapper flight model power supply was reviewed and the data compared to the relevant specification. The power supply was found to be within specification. Final test data for outut voltage regulation and ripple, efficiency, over and undervoltage protection, telemetry, impedances, turn-on requirements, and input current limits are presented.

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NASA NTRS1982

Spatially Characterizing Effective Timber Supply

The structure of a computer-oriented cartographic model for assessing roundwood supply for generation of base load electricity is discussed. The model provides an analytical procedure for coupling spatial information of harvesting economics and owner willingness to sell stumpages. Supply is characterized in terms of standing timber; of accessibility considering various harvesting and hauling factors; and of availability as affected by ownership and residential patterns. Factors governing accessibility to timber include effective harvesting distance to haulic roads as modified by barriers and slopes. Haul distance is expressed in units that take into account the relative ease of travel along various road types to a central processing facility. Areas of accessible timber are grouped into spatial units, termed 'timbersheds', of common access to particular haul road segments that belong to unique 'transport zones'. Timber availability considerations include size of ownership parcels, housing density and excluded areas. The analysis techniques are demonstrated for a cartographic data base in western Massachusetts.

Berry, J. K.↗

NASA NTRS1986

Control Electronics for Solar/Flywheel Power Supply

Control circuit automatically directs flow of electrical energy to and from motor with flywheel that constitutes storage element of solar-power system. When insolation is sufficient for charging, power is supplied by solar-cell array to load and motor. During periods of darkness, motor made to act as generator, drawing kinetic energy from flywheel and supplying it to load.

Nola, F. J.↗

NASA NTRS1986

Advanced Vapor-Supply Manifold

Advanced vapor-supply manifold solves problem of manifold purging. Design virtually eliminates dead gas volumes in manifold system. System incorporates special valve into manifold in way that leaks and contamination problems of previous systems, which use tees and three-port valves, are minimized or eliminated in both main manifold line and in supply line. Of considerable use in gas manifold systems where even small amounts of gaseous impurities constitute problem or where more than one gaseous material used in single system.

Clark, I. O.↗

NASA NTRS1984

Food Acquisition: Food Ingredients, Raw Materials and Supply

The kind of food supply system that will serve the space station in coming years is considered. The direction and rate of evolution of space food service systems is also considered and what is needed to supply appropriate food to space station crews. Innovations in food sourcing, recipe development, pre-preparation, packaging, preservation, presentation, consumption and waste disposal are discussed. The development and validation of preparation systems and ingredients which minimize demands on crew time and provide maximum eating enjoyment is outlined.

Wheat, D. W.↗

NASA NTRS1985

High voltage power supply

A high voltage power supply is formed by three discrete circuits energized by a battery to provide a plurality of concurrent output signals floating at a high output voltage on the order of several tens of kilovolts. In the first two circuits, the regulator stages are pulse width modulated and include adjustable ressistances for varying the duty cycles of pulse trains provided to corresponding oscillator stages while the third regulator stage includes an adjustable resistance for varying the amplitude of a steady signal provided to a third oscillator stage. In the first circuit, the oscillator, formed by a constant current drive network and a tuned resonant network included a step up transformer, is coupled to a second step up transformer which, in turn, supplies an amplified sinusoidal signal to a parallel pair of complementary poled rectifying, voltage multiplier stages to generate the high output voltage.

Ruitberg, A. P.↗

NASA NTRS1985

Frequency response of a jet engine test facility air supply system

The frequency response of a laboratory scale model of a portion of the air supply system of an engine test facility is obtained both experimentally and using one-dimensional, small-signal, distributed parameter theory. The effects of line terminations and mean flow are considered. Good agreement between experiment and theory is obtained. Predictions are extended to a full scale test facility air supply system operating under several possible test conditions.

Franke, M. E.↗