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This paper presents an outline of the power and energy requirements of a human elbow and gives a discussion on the means by which these requirements can be met. Reasons are given for the choice of a system using batteries for energy storage and direct electric drive by a motor and gearbox. The gearbox is of an unusual type, using ‘harmonic drive’ elements, which permit the motor to be installed transversally at the elbow. The gear reduction unit is described in detail. The paper also discusses the problems inherent in controlling a motor with large stall current in such a way that most efficient use is made of the energy stored in the battery, and two control circuits are described which meet the requirements.

A thermoelectric generator has been combined with thermal energy storage to produce electricity during simulated 90-min orbits with 55 min of sunlight and 35 min of darkness. The experimental model has demonstrated the thermodynamic feasibility of converting solar energy to electric power for space application. The generator produced constant power (± 7%) during simulated orbits in a space chamber and has also operated successfully utilizing natural solar energy. Projection of the feasibility model indicates that a generator with an output of 150 w coupled with a collector-concentrator of 8-ft dia can be built. This system can operate with 0.50 orientation error with a specific power of 2.14 w/lb. Very precise orientation would reduce the area of the collector by 17.5% and increase the specific power, excluding orientation equipment, to 2.3 w/lb. Analysis of the system shows that the thermal storage feature has a significant weight advantage over electrochemical energy storage. This feature also makes the system feasible from an operational standpoint since temperature excursions and warm-up period after solar darkness are eliminated.

As a result of the energy conversion and storage research underway at Oklahoma State University since 1961, several components needed to engineer a continuous-duty energy system operating on replenishable solar energy have been developed to the prototype stage and are being tested. This paper presents and discusses these components and how they fit together in the solar energy systems envisioned for the long-term and immediate future. A simplified economic analysis of solar energy systems is presented, and the calculated generation costs are compared with those of conventional fuel burning systems for different fuel costs, load factors and interest rates. One result of this study is that wind energy systems, costing $125 to $150 per installed kW and pumping power directly into a.c. mains for 20 per cent of the time using the field-modulated generating systems developed at OSU, are competitive with conventional systems costing $250 to $350 per installed kW operating at a load factor of 80 per cent and fuel cost of $0·50 per MBtu. More such comparisons are included in the text of the paper.

This paper indicates the market for a van-type electric vehicle, provides the physical description, and presents the electrical principle of operation of a frequency modulated and pulsewidth modulated power system applied to a 27-kW three-phase squirrelcage age induction motor. This ac drive system, which represents the third generation in design, has been placed in a Dodge B-300 high production van of 2700 kg gross vehicle weight. The electrical energy is stored in 24 6-V 220-Ah batteries providing 144 V. Design speeds of the electronics for the vehicle are up to 90 km/h. Computer developed power factor and efficiency curves are given for the motor for the entire range of operating speeds. Electrical charge in the batteries may be replaced either by quick interchange of batteries a or through utilization of a 12-kg on-board charger with an electrical demand of 6 kW from a 220-V single-phase main. Finally, the paper discusses the economics of the ac drive LinearVan.

The electrical power control and conditioning subsystem developed under NASA* Contract NASl-4479 represents an integrated, operational design for the Manned Orbital Research Laboratory (MORL) to support 6 men in space for 5 years. The power conditioning systems discussed in recent engineering papers have generally been planned for unmanned craft or were for optimizations of specific electrical loads of modest demand levels, and used conventional battery, solar cell/battery, or fuel cell energy sources. Therefore, an advanced design to supply a greater (by an order-of-magnitude) electrical demand from a radioisotope-dynamic generator drive system, and which meets manned spacecraft design criteria, represents a significant and unique contribution to aerospace electrical design. This paper identifies and discusses (1) the unique electrical design criteria and constraints associated with the radioisotope Brayton cycle drive system, (2) the tradeoff considerations which were necessary to optimize the total system with respect to speed, frequency, and efficiency, (3) the rationale for the selection of the alternator and the frequency converters, and (4) the distribution system design criteria which were established to assure flexibility, efficiency, maintainability, and safe emergency operations. The control system concept and its integration with the energy storage subsystems will also be discussed.

The load conditions under which motors driving continuous running rolling mills operate is generally understood, and the advantage to be obtained by using a suitably designed flywheel is well known. Owing to the rapidly fluctuating load, some system of energy storage capable of performing a large amount of work for short periods must obviously be of considerable value not only from the standpoint of motor operation but also from that of power supply. Several papers have been read before this Institute dealing with the question of the action of flywheels with such loads and the advantage has been clearly demonstrated. The value of flywheels can be best appreciated when used with mills with very high and short peak loads, such as a blooming mill, where loads up to 10,000 h.p. for one or two seconds are not infrequent. The antithesis of this type of mill is the reversing mill where every effort is made to reduce the flywheel effect to a minimum so that the accelerating force required may be kept within reasonable limits. Most engineers connected with industrial work are familiar with the development of electrically driven continuous running mills but the development of the reversing mill is not generally appreciated except by those more or less connected with their design and operation. The object of this paper is to briefly review some of the more important points in its design and operation.

This paper describes an experimental investigation of frequency memory in a recirculating amplifier storage device. The objective of the investigation was to determine what mechanism caused injected energy to shift to preferred storage frequencies. Using fast-acting crystal switches, the output energy was selectively viewed, and it was found that the energy in any circulation when viewed separately was of the input frequency. The spectrum photographs which are included in the paper show that the recirculating amplifier when operating with an open loop gain greater than unity does not oscillate at preferred frequencies.

This paper was prepared for the Second Midwest Oil and Gas Industry Symposium of the Society of Petroleum Engineers of AIME, to be held in Indianapolis, Ind., March 28–29, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract The electrical power industry has turned strongly over the last decade to gas turbine and pumped hydro peaking systems to supplement power from the large base load power plants. Petroleum fuel shortages and limitations of acceptable pumped hydro sites are seriously restricting these sources of peaking power. Underground compressed-air storage for electrical power generation combines many of the best qualities of the two peaking systems while eliminating or peaking systems while eliminating or minimizing undesirable aspects of both. Aquifer reservoirs ideally lend themselves to this type of large scale energy storage and simplify many of the problems associated with energy conversion. Introduction The availability of low cost electrical energy in this country and all industrialized nations has resulted principally through the practice of building larger and larger power practice of building larger and larger power generating complexes. These installations must be operated continuously at or near maximum output to yield electricity efficiently and at low costs. For this reason they are only suitable for the production of the base load electricity, that production of the base load electricity, that is, the minimum nighttime load requirements. Base load coal or nuclear plants supply the bulk of the total electric energy (kilowatt hours) of a power system. Peak demand periods, however, occur for a few hours a day and consume a relatively small portion of total energy but necessitate having portion of total energy but necessitate having generating capacity two or three times greater than the base load. The generating plants which supplement the base load power plants which supplement the base load power production are smaller and fast responding production are smaller and fast responding plants which normally operate on oil, refined plants which normally operate on oil, refined oil products or natural gas. These plants must also be relatively inexpensive in terms of capital cost per kw of generating capacity because they remain idle much of the time. Over the past decade the trend toward larger base load plants has been accompanied by a trend toward gas turbines for providing peak power. peak power.

This paper gives an overview of typical components, their performance, size, shape, weight, and relationships to each other, and how they fit together in electric vehicle applications. Vehicle designs covered are golf cars, personnel carriers, people carriers, riding and walk-behind lawn mowers, 2-and 3-wheeled bikes, outboard motors, and floor care sweepers and scrubbers.

The problem of obtaining maximum hydro energy from the various plants of the Columbia River is one phase of a broader problem that the staff at the Bonneville Power Administration (BPA) has designated the economy loading problem, which may be defined in a broad sense as follows: To plan, design, and operate the hydro and electric system so that maximum hydro energy will be delivered economically to the load as required, without undue sacrifice of system reliability during normal or emergency operation. While direct BPA system generation is all hydro, interconnections with other systems having some steam generation will make it necessary to include solutions in which the cost of thermal energy is considered. A number of papers have been presented on economy loading as applied to thermal generation and to system transmission losses. However, up to now relatively little information has been published on obtaining maximum energy from hydro stations. A description of all the phases of the general problem of economy loading will not be attempted in this paper, which will investigate only an individual phase. It should be emphasized, however, that, to obtain correct solutions, all components are interrelated and should be considered simultaneously. Unfortunately, the complexity of such simultaneous solutions may make them impossible to achieve from a practical standpoint.

Historically, aircraft inertial navigation system (INS) batteries have utilized vented nickel-cadmium batteries for emergency DC power. The United States Navy and Air Force developed separate systems during their respective INS developments. The Navy contracted with Litton Industries to produce the LTN-72 and Air Force contracted with Delco to produce the Carousel IV INS for the large cargo and specialty aircraft applications. Over the years, a total of eight different battery national stock numbers (NSNs) have entered the stock system along with 75 battery spare part NSNs. The Standard Hardware Acquisition and Reliability Program is working with the Aircraft Battery Group at Naval Surface Warfare Center Crane Division, Naval Air Systems Command (AIR 536), Wright Laboratory, Battelle Memorial Institute, and Concorde Battery Corporation to produce a standard INS battery. This paper discusses the approach taken to determine whether the battery should be replaced and to select the replacement chemistry. The paper also discusses the battery requirements, aircraft that the battery is compatible with, and status of Navy flight evaluation. Projected savings in avoided maintenance in Navy and Air Force INS Systems is projected to be $14.7 million per year with a manpower reduction of 153 maintenance personnel. The new INS battery is compatible with commercially sold INS systems which represents 66% of the systems sold. >

In the following paper, the character of the quantity known as reactive volt-amperes is first discussed and its dependence on the assumption of a definite type of periodicity is brought out, this in contrast to certain other a-c quantities. It is pointed out that on account of the rather complicated relation that it bears to the flow of energy in an electric circuit serious difficulties are met in its measurement except in the simpler conditions of balanced voltages, in a polyphase circuit, and sinusoidal waves. Two procedures are outlined which though they are not premised on balanced voltages have frequency and wave form limitations. In the latter part of the paper, the relation of the quantity of energy that surges in an a-c circuit in which there is energy storage, to the average flow of energy is considered, and advantages of this conception as a basis for rates are indicated. Finally, it is pointed out that reactive volt-amperes is of the nature of a complementary quantity rather than a specific activity of the electric circuit which when suitably combined with power gives volt-amperes.

Since the beginning of earth, ultra-violet rays from the sun have been splitting water molecules in the upper reaches of the atmosphere, producing hydrogen and oxygen. At the same time, photosynthesis has been sustaining life on earth by utilizing the longer wavelengths of sunlight to split carbon and water molecules forming carbohydrates and oxygen. Attempts are being made to imitate these processes for the purpose of harnessing solar energy for man's use. This paper presents a state-of-the-art review of photolysis of water by sunlight with consequent energy storage in the molecular bonds of hydrogen and oxygen. The photocatalytic solar energy conversion methods reviewed are classified according to the photosensitizer type. That includes catalysts such as compound salts, compound semi-conductor crystals and photosynthetic dyes. An assessment of these methods concludes that photolysis of water as a solar energy conversion process does not seem feasible at present or for the immediate future. On the other hand, efficiency estimates indicate that with research emphasis this unconventional energy conversion method may prove to be a long-term alternative in harnessing solar energy for man's use.

Linear equations are shown with schematic diagrams which together describe the automotive dynamic model. However, the principal intent of the paper is not to study the dynamics of automotive operations. The schematic diagrams of each sub-system are presented to indicate the possible points of energy storage and dissipation and how they relate to the continuity of energy. From the sub-system diagrams it is now possible to generate energy and matter balances for the automotive system. The final energie matrix expression (eqn 49), which relates to all components of the system, is developed.

In this paper, the explosively increasing demand for energy storage capacitor applications is discussed with particular reference to the various special characteristics required and how they affect the cost, mechanical configuration, circuitry, and protection requirements. Of particular importance at this time, there is included a discussion of means of accomplishing lower inductance and "Q" factor improvement over conventional design. A brief discussion of capacitor fundamentals contributing to the control of discharge waves is presented to illustrate the need for precise determination of circuit characteristics and electrical parameters. Several application problems are discussed, illustrating all of the factors pertinent to the design requirements, and how to obtain them. Since most of these installations represent considerable investment and frequently the need for high reliability, means for protection both against voltage overshoot and isolation in the event of unit failure is also discussed. Thus, the information presented establishes the criteria for selection of large banks of capacitors under the most favorable economic and technical comditions, along with an assurance of reliable performance without excessive unused safety factor dollars.

This paper first discusses the effect of limited energy hydro capacity, including pump-storage hydro capacity, on system installed capacity requirements, showing that, for a combined thermal and hydro system, the capacity value of the hydro depends primarily on the reduction in the maximum thermal generation requirements that can be effected over the heavier daily peak load hours. Such determinations are inseparable from the load characteristics and the effect of prior installed limited energy capacity. Second, a mathematical basis is presented for the evaluation of the relative economics of alternative potential pump-storage sites based on operating requirements, and for the determination of the most economical size of development for various conditions.

Capacitive energy storage is one of the oldest forms of energy storage for pulsed power requirements. Most energy storage capacitors are made of Kraft paper and aluminum foil and impregnated with castor oil. A typical capacitor stores ~ 3000 joules at voltage ratings of 5 kV - 100 kV. Two types of switches are used for capacitor bank switching, ignitrons and pressurized spark gaps. Ignitrons are commercially available, have a wide voltage operating range and are easy to trigger. However, they are limited to ~ 20 kV for most applications and they will prefire. Spark gaps can be designed for reliable operation at almost any voltage level but they are rarely commercially available. Most spark gaps do not operate satisfactorily below 50% of their design voltage and they require a more complicated trigger system than ignitrons. Low inductance coaxial cable has been developed for capacitor bank transmission systems. It is relatively inexpensive and commercially available. Parallel plate transmission lines can be designed to accumulate large amounts of current and conduct it to a concentrated load but careful attention must be given to the containment of the magnetic forces involved. Large numbers of ignitrons can be triggered with a simple trigger circuit that will be described. A circuit is also given to automatically trigger a crowbar ignitron. A pulse forming network circuit is presented which uses inductive voltage addition to generate an 800 kA pulse rising in 100 nsec with a pulse length of 500 nsec.

This is a companion paper to an earlier one.1 The computer program described is divided into three parts: a) the determination of the coefficientsfor(l), (2), and (4) of Watchon1 for the best fit to the calculated cost and plant pumping ratio data, b) the determination of the lowest average unit investment cost, and other pertinent information, to be shown later, for each of the potential sites for various conditions, and c) the arrangement of the results of part b in the order of preference. All the programs are written in Fortran for the 7074 computer.

Ion engines have been found to be demanding loads for high-voltage solid-state power-conditioning systems. This is due, in large part, to the tendency of these engines to undergo frequent and severe electrical arcing. The unusual ruggedness and efficiency requirements for such power systems are in direct conflict with the requirement for an extremely light weight. This paper describes a six-stage nondissipatively-regulated modular conversion system in which the use of an unconventional method for accomplishing dc-to-dc conversion, current-feedback base drive for the power transistors, and a relatively high (10 kc/s) intermediate conversion frequency results in an efficient and lightweight power-conditioning system with excellent protection characteristics. In this modular 2000-volt 1600-watt system, voltage conversion is accomplished by means of multiple-winding energy-storage transformers, each containing a core with an air gap. These transformers are caused to absorb energy from the source on one half cycle and to discharge energy into the output filter and load on the succeeding half cycle. This configuration makes possible a converter in which no semiconductor element is subjected to an immediate or abrupt transient as a result of a short circuit across the high-voltage output; protection schemes need not be elaborate. This ?energy-pumping? conversion technique, in which the special energy-storage transformers perform multiple functions involving not only voltage conversion but also filtering, nondissipative regulation, and system protection, results in a system which is physically very simple.

Several experimental vehicles have been built by the General Motors Corporation to investigate the technical feasibility of a battery-powered electric car using a variable speed induction motor. This paper describes the control scheme for the first experimental car?Electrovair I.

An analytical and experimental study of the energy storage in a fabric element is pre sented in this paper. The flexural and the tensile energies are evaluated and compared for a better understanding of filament response under static loadings. Past analyses of textile fabrics have been based on various assumptions regarding the storage of strain energy in the fabric; as a result of this study it appears that an analysis that is based on tensile energy storage (and that neglects flexural energy storage) may adequately describe the behavior of the common fabric configurations.

This paper analyzes flight plans for spacecraft operating at thrust levels tha t are inuch smaller than the local gravitational force, e.g., electrical propulsion near the Earth. The thrust is limited by the average power generated. For power limited flight, it has been suggested by Irving and Blum tha t the shortest flight times are obtained when operating at constant (thrust) acceleration. However, there was no consideration of the use of energy storage which permits more freedom for programming the thrust while still utilizing all the available energy. In particular, the electric energy can be stored in batteries over a portion of an orbit revolution and used to provide a short thrus t impulse at a point along the orbit. The batteries would be recycled each revolution and used repeatedly. The performance with and without energy storage is compared for two types of missions, both in the gravitational field of the Earth: Round trips from small to larger circular orbits, and rendezvous maneuvers between orbits at low altitudes. It is shown in case 1 tha t even with the extra weight of the storage batteries, flight plans can be achieved in some cases which reduce both the flight t ime and the propellant requirements. For case 2 many flight plans require tha t thrust be applied at only limited portions of the orbit. With energy storage all the available energy can be utilized, thereby substantially decreasing the flight t ime and the guidance problem.

This paper deals with the problem of obtaining the optimal scheduling of a pumped storage hydroelectric plant in combination with, several interconnected power systems. A special case of interest is the scheduling of pumped storage when the plant is jointly owned by several electric utilities. A mnathematical model is developed in order to determine the power flows between the different power systems and the pumped storage plant as well as the water flows inside the plant.

Pumped storage equipment has played a significant role in the storage and distribution of water at Oroville. This paper describes the mechanical design features of the pump/turbines installed in the Edward Hyatt Power Plant, and the niany tests performed during design and startup to achieve water delivery requirements. The experiences gained from this installation should stimulate the further development of pumped storage by utilities and consulting engineers.

This paper describes how a digital computer program intended for system planning studies was used to investigate several questions related to pumped storage planning and operation. Among the items investigated were reservoir size, the influence of cycle efficiency on pumped storage capacity factor and operating cost, and the effect of load forecasting deviations on system economy. A brief description of the program is provided.

Superconducting coils have been utilized in a broad range of applications which continues to expand. Initially, they were used for small physics experiments in the laboratory. More recent applications involve superconducting coils on a scale that would have been unrealistic only a few years ago. This paper is concerned with some of these applications. After a brief review of the main characteristics of superconductors and superconducting windings in general, specific applications are discussed. These include high-energy physics, controlled thermonuclear fusion, magnetohydrodynamic power generation, inductive energy storage, and levitation of high-speed ground vehicles. Photographs and illustrations are included to describe some of the existing systems as well as some systems which are presently conceptual in nature.

This paper analyses a proposed accelerator, less than 1 meter long, capable of accelerating bunched electrons with a peak current of 100 A for a period of 50 rf cycles (20 nsec). The accelerator consists of an S-band disk-loaded circular waveguide, similar in design to the SLAC machine, incorporated into a waveguide resonant ring. Analysis of this system indicates that significant power buildup can occur if the length of the accelerator part of the ring is less than 1 meter. Further analysis of the power buildup and energy storage is made for a variety of rings having an accelerator section which is three, four, and five wavelengths long. Following the initial buildup of ring energy a beam of current bunched into 1/6th wavelength (60°), having a peak value of 100 A and an initial energy of 100 kV, is injected into the first cavity of the accelerator. Such a beam would extract half of the energy within the ring in approximately 20 nsec and have a nominal output energy of 10 MeV. By operating at 100°K, five such accelerators could be pumped by the same power source, thus increasing the output energy level to 50 MeV. The problem of handling a 100-A beam at low velocities is also investigated and a method utilizing space-charge neutralization by ionized gas is discussed.

Traditionally the phenomenological constitutive relations for piezoelectric materials explicitly relate the electric displacement D/spl ovbr/ the electric intensity E/spl ovbr/, the stress tensor, and the strain tensor. This paper presents a new formulation for the theory of coupled wave interactions in a class of important hexagonal piezoelectric devices; here an equivalent dielectric description explicitly involving only D/spl ovbr/ and E/spl ovbr/ replaces (without approximation) the traditional formulation. The new formulation supplies the foundation for a new determination of power flow and energy storage on a basis broad enough to include the effects of diffusion and collisions on multivelocity multispecies carrier streams. The results, when specialized to a single-velocity single-species carrier stream, differ significantly with others recently proposed for those circumstances. The general results display a considerable degree of compactness and simplicity and are "electrically invariant" in that they hold for insulating, photoconducting, and semiconducting piezoelectric materials without any change in basic form.

Site Investigations of Pumped Storage Facilities is the topic of this paper. 3205 p 233-51.

In this paper I will discuss several areas in energy systems where materials research and development will lead to improvements in the efficiency of energy utilization. I will consider improvements in current technology as well as new technologies.

The high cost of a solar energy collector has presented a stumbling block to the generation of large amounts of useful power from solar radiation. The present paper discusses attempts made to design an economically viable system of power generation using the surface of the tropical oceans as a solar collector, and the deep cold water as a heat sink. No new technology need be developed to make such a system technically feasible. Ingenuity is required, however, in envisioning methods of performing the various necessary functions of such a system at the lowest possible cost.If indeed such power systems have a high probability of being economically viable, a new energy economy is to be developed. The author indicates how physicists have the proper training to guide the development of such a new energy economy.

This paper describes a scheme whereby surplus power during reduced demand periods is used to liquefy air which can be stored and used later to supply peak power with considerably reduced fuel requirements. All the component processes of the system are established techniques, are very largely automatic in operation, and the location is on-site. Such a system can be constructed and placed on-line in a minimum of time and with greatly reduced pollution control requirements. It is capable of considerable flexibility in the use of the liquefied product as air or as the separated constituents as O2 and N2, and thus furnishes a number of ways of optimum utilization as operating conditions and economic circumstances change.Copyright © 1974 by ASME

Basic techniques are presented for determining the charge condition of electric-vehicle propulsion batteries of both the lead--acid and nickel--cadmium types. The techniques presented include those employing measurement of battery parameters, such as electrolyte properties, voltage, and internal resistance, and those utilizing coulometric measurements. An application example employing the coulometric approach is described to demonstrate the usefulness of an accurate battery charge condition signal in an automated material handling car system.