Postflight Evaluation of Atlas-Centaur AC-4 (Launched December 11, 1964)
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Atlas-Centaur AC-18 performance evaluation for Applications Technology Satellite ATS-5 mission
The Atlas-Centaur with the ATS-5 spacecraft was successfully launched from Eastern Test Range on August 12, 1969, and the ATS-5 was placed in the required highly elliptical transfer orbit with apogee near synchronous altitude. From this orbit the ATS-5, using its apogee motor, achieved the desired near-synchronous circular equatorial orbit. All launch vehicle systems performed satisfactorily.
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ACS avionics systems review
Items covered in this study include: (1) refining the baseline avionics system design; (2) clarification of key issues for RFP; and (3) refining the baseline avionics system costs.
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AC impedance of silicon solar cells.
The equivalent source impedance of a solar array is an important parameter in the design and analysis of solar array power conditioning equipment. Laboratory impedance tests have been performed on individual silicon solar cells and the test results have been correlated with P-N junction theory as developed by Shockley. The impedance has been broken into resistive and reactive components. The impedance has been expressed as a function of DC operating point and frequency. A practical application of the individual cell characteristics is presented in a solar array simulator design.
Zerbel, D. W.↗
Ion-ion instability induced by ac electric fields.
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Papadopoulos, K.↗
DC-to-AC inverter ratio failure detector
Failure detection technique is based upon input-output ratios, which is independent of inverter loading. Since inverter has fixed relationship between V-in/V-out and I-in/I-out, failure detection criteria are based on this ratio, which is simply inverter transformer turns ratio, K, equal to primary turns divided by secondary turns.
Ebersole, T. J.↗
Ac electronic tunneling at optical frequencies
Rectification characteristics of non-superconducting metal-barrier-metal junctions deduced from electronic tunneling have been observed experimentally for optical frequency irradiation of the junction. The results provide verification of optical frequency Fermi level modulation and electronic tunneling current modulation.
Faris, S. M.↗
AC adapter for fuel-flow sensor
Readily-available fuel meters can be used to aid in fuel oil conservation in homes and commercial buildings. Device also includes failure monitor that activates warning light and horn if meter fails.
Millman, L. L.↗
Characteristics of corona impulses from insulated wires subjected to high ac voltages
Corona discharges arise due to ionization of air or gas subject to high electric fields. The free electrons and ions contained in these discharges interact with molecules of insulating materials, resulting in chemical changes and destroying the electrical insulating properties. The paper describes some results of measurements aimed at determining corona pulse waveforms, their repetition rate, and amplitude distribution during various randomly-sampled identical time periods of a 60-Hz high-voltage wave. Described are properties of positive and negative corona impulses generated from typical conductors at various test high voltages. A possible method for calculating the energies, densities, and electromagnetic interferences by making use of these results is suggested.
Doreswamy, C. V.↗
Save power in AC induction motors
Relatively simple and inexpensive circuitry improves power factor and reduces power dissipation in induction motors operating below full load. Electronic control loop conserves energy by reducing voltage applied to lightly loaded motor. Circuit forces motor to run at constant predetermined optimum power factor, regardless of load or line voltage variations. Solid-state switch varies voltage.
Nola, F. J.↗
Primary-controlled ac-to-dc power converter
Switch operation of power transformer/rectifier dc power supply requires fewer turns of larger wire and regulates output voltage.
Harper, P.↗
Capacitors, thermal rating/derating (ac-dc operation)
Application techniques for determining performance and ratings of cased capacitors under combined operation as a function of the actual operating conditions are described. Thermal impedances between the case and external environment and between the internal hot spot and case are taken into account.
Borough, J. W.↗
Power factor control system for ac induction motors
A power control circuit for an induction motor is disclosed in which a servo loop is used to control power input by controlling the power factor of motor operation. The power factor is measured by summing the voltage and current derived square wave signals.
Nola, F. J.↗
Advanced single permanent magnet axipolar ironless stator ac motor for electric passenger vehicles
A program was conducted to design and develop an advanced-concept motor specifically created for propulsion of electric vehicles with increased range, reduced energy consumption, and reduced life-cycle costs in comparison with conventional systems. The motor developed is a brushless, dc, rare-earth cobalt, permanent magnet, axial air gap inductor machine that uses an ironless stator. Air cooling is inherent provided by the centrifugal-fan action of the rotor poles. An extensive design phase was conducted, which included analysis of the system performance versus the SAE J227a(D) driving cycle. A proof-of-principle model was developed and tested, and a functional model was developed and tested. Full generator-level testing was conducted on the functional model, recording electromagnetic, thermal, aerodynamic, and acoustic noise data. The machine demonstrated 20.3 kW output at 1466 rad/s and 160 dc. The novel ironless stator demonstated the capability to continuously operate at peak current. The projected system performance based on the use of a transistor inverter is 23.6 kW output power at 1466 rad/s and 83.3 percent efficiency. Design areas of concern regarding electric vehicle applications include the inherently high windage loss and rotor inertia.
Beauchamp, E. D.↗
Motor power control circuit for ac induction motors
A motor power control of the type which functions by controlling the power factor wherein one of the parameters of power factor current on time is determined by the on time of a triac through which current is supplied to the motor. By means of a positive feedback circuit, a wider range of control is effected.
Nola, F. J.↗
Coupling an induction motor type generator to ac power lines
A system for coupling an induction motor type generator to an A.C. power line includes an electronic switch means that is controlled by a control system and is regulated to turn on at a relatively late point in each half cycle of its operation. The energizing power supplied by the line to the induction motor type generator is decreased and the net power delivered to the line is increased.
Nola, F. J.↗
Power control for ac motor
A motor controller employing a triac through which power is supplied to a motor is described. The open circuit voltage appearing across the triac controls the operation of a timing circuit. This timing circuit triggers on the triac at a time following turn off which varies inversely as a function of the amplitude of the open circuit voltage of the triac.
Dabney, R. W.↗
Evaluation of semiconductor devices for Electric and Hybrid Vehicle (EHV) ac-drive applications, volume 2
Test data of switching times characterization of bipolar transistors, of field effect transistor's switching times on-resistance and characterization, comparative data of field effect transistors, and test data of field effect transistor's parallel operation characterization are given. Data is given in the form of graphs.
Lee, F. C.↗