Direct support and general support maintenance manual : water purification unit, van type, body mounted, electric motor driven, AC, DC, 115, 208 V, single and 3 phase, 60 hertz, 1/20 to 2 hp, 1500 gph, model EMC-1500S, NSN 4610-01-037-8746, EMC Industries Inc., DAAKO1-76-C-5661.

"1 August 1979."

Field and depot maintenance manual : generator set, diesel engine precise power; 100 KW, AC, 120/208 V, 240/416 V, 3 phase, 60 cycle at 1800 RPM, 83.3 KW, 120/208 V 240/416 V, 3 phase, 50 cycle at 1500 RPM; skid mounted (Detroit Diesel Divn. General Motors Corp. model 6910A) FSN 6115-798-3444.

Includes index.

Operator, organizational, direct support, and general support maintenance manual : generator set, gasoline engine driven, skid mounted, tubular frame, 3 kw, 3 phase, AC, 120/208 and 120/240 volts, 28 V, DC (less engine) : DOD model MEP-016A ... hertz 60 ... NSN 6115-00-017-8237 ....

"August 1976."

Operator, organizational, DS, and GS maintenance manual : generator set, diesel engine driven, liquid cooled, AC, 100 KW, 120 208, 240 416 volt, 3 phase, 4 wire, 50 60 HZ, skid mtd (Jeta power model D8001M) FSN 6115-156-4342).

"July 1970."

Operator, organizational, and direct support maintenance manual : generator sets, gasoline engine w/carrying sound housing case, PU-422B/U, 0.4 KW, AC, 115V, 400 Hz and 100V, DC, 29.3V, Admiral model GJ4266 ... PU-532/PPS-4, 0.3 KW, AC, 115V, 400 Hz, 30V, 17 amp, 24V, 2.5 amp, DC, Admiral model G-2633, FSN 6115-889-1212, Henry Spen model 909238-1B, FSN 6115-436-4230.

"March 1973."

Organizational, direct support , and general support maintenance repair parts and special tools list (including depot maintenance repair parts and special tools) for power supply/DC dual, (0-40VDC/0-1.5A), (NSN 6130-00-065-6811).

Includes index.

Operator's, organizational, direct support and general support maintenance manual for power supply, dual DC, (H-P model 6255A), (NSN 6130-00-065-6811).

Includes index.

Christiani Adolphi Thuldeni : Historia ab anno Christi M.DC.LII. in praesens usque tempus ; qua decem Germaniae in S.R. Imperio circuli, Octoviri Electores liique principes cum singulorum religionibus moenissimè describuntur ; ac res propè omnes in Francia, Suedia, Polonia, Anglia, caeterisque Europae totius regnis, cum cura & fide commemorantur ; [s]ubiecti sunt in annos singulos tractatus historico-politici, è quibus melior omnium propè bello & pace historiarum cognitio exsistit.

Prgt.

Magnetic circuits and transformers; a first course for power and communication engineers,

"A publication of the Technology Press, Massachusetts Institute of Technology."

Central Valley Project Improvement Act : hearings before the Subcommittee on Water and Power of the Committee on Energy and Natural Resources, United States Senate, One Hundred Second Congress, first session, on S. 484 ... Los Angeles, CA, March 18, 1991; Washington, DC, May 6, 1991; Sacramento, CA, May 30, 1991.

"San Francisco, CA, September 4, 1991"--Pt. 2.

Interactions within heterogeneous systems of uncontrolled rectifiers for aircraft electrical power systems

There is an increase in the use of multi-pulse, rectifier-fed motor-drive equipment on board more-electric aircraft. Motor drives with feedback control appear as constant power loads to the rectifiers, which can cause instability of the DC filter capacitor voltage at the output of the rectifier. This problem can be exacerbated by interactions between rectifiers that share a common source impedance. In order that such a system can be analysed, there is a need for average, dynamic models of systems of rectifiers. In this study, an efficient, compact method for deriving the approximate, linear, large-signal, average models of two heterogeneous systems of rectifiers, which are fed from a common source impedance, is presented. The models give insight into significant interaction effects that occur between the converters, and that arise through the shared source impedance. First, a 6-pulse and doubly wound, transformer-fed, 12-pulse rectifier system is considered, followed by a 6-pulse and autotransformer-fed, 12-pulse rectifier system. The system models are validated against detailed simulations and laboratory prototypes, and key characteristics of the two system types are compared.

Two way power flow using GTO thyristors

Two-way power flow is nothing new and has been in practical use using line commutated converters for at least 50 years. With these types of converters, reversal of power flow can be achieved by increasing the firing angle of the devices beyond 90 degrees thus producing a negative DC voltage. Line commutated converters have several known disadvantages including: the direct current cannot be reversed, the power factor decreases when the firing angle increases and the harmonics are high on the line current. To tackle the above problems a forced commutated converter can be used. The power factor can be unity and the harmonics can be reduced. Many researchers have used PWM with different control techniques to serve the above purposes. In each converter arm, they used a forced commutated device with an antiparallel diode. Under the rectification mode of operation the current path is preponderantly through the diodes and under the inverter operation the current flows preponderantly through the forced commutated devices. Although their results were encouraging and gave a unity power factor with nearly sinusoidal current, the main disadvantage was that there were difficulties in controlling the power factor when the system is needed to operate at lagging or leading power factor. In this work, a new idea was introduced by connecting two GTOs antiparallel instead of a diode and a GTO. A single phase system using two GTO converters which are connected in series was built. One converter operates as a rectifier and the other converter operates as an inverter. In the case of the inversion mode and in each inverter arm one GTO is operated as a diode simply by switching it always on and the other antiparallel GTO is operated as a normal device to carry the inverter current. In case of the rectification mode, in each arm one GTO is always off and the other GTP is operated as a controlled device. The main advantage is that the system can be operated at lagging or leading power factor.

Damage analysis of bridge structures using vibrational techniques

Much research is currently centred on the detection of damage in structures using vibrational data. The work presented here examined several areas of interest in support of a practical technique for identifying and locating damage within bridge structures using apparent changes in their vibrational response to known excitation. The proposed goals of such a technique included the need for the measurement system to be operated on site by a minimum number of staff and that the procedure should be as non-invasive to the bridge traffic-flow as possible. Initially the research investigated changes in the vibrational bending characteristics of two series of large-scale model bridge-beams in the laboratory and these included ordinary-reinforced and post-tensioned, prestressed designs. Each beam was progressively damaged at predetermined positions and its vibrational response to impact excitation was analysed. For the load-regime utilised the results suggested that the infuced damage manifested itself as a function of the span of a beam rather than a localised area. A power-law relating apparent damage with the applied loading and prestress levels was then proposed, together with a qualitative vibrational measure of structural damage. In parallel with the laboratory experiments a series of tests were undertaken at the sites of a number of highway bridges. The bridges selected had differing types of construction and geometric design including composite-concrete, concrete slab-and-beam, concrete-slab with supporting steel-troughing constructions together with regular-rectangular, skewed and heavily-skewed geometries. Initial investigations were made of the feasibility and reliability of various methods of structure excitation including traffic and impulse methods. It was found that localised impact using a sledge-hammer was ideal for the purposes of this work and that a cartridge `bolt-gun' could be used in some specific cases.

A converter compensator for power factor control in 3-phase induction machines

The advent of the harmonic neutralised shunt Converter Compensator as a practical means of reactive power compensation in power transmission systems has cleared ground for wider application of this type of equipment. An experimental 24-pulse voltage sourced convector has been successfully applied in controlling the terminal power factor of a 1.5kW, 240V three phase cage rotor induction motor, whose winding has been used in place of the usual phase shifting transformers. To achieve this, modifications have been made to the conventional stator winding of the induction machine. These include an unconventional phase spread and facilitation of compensator connections to selected tapping points between stator coils to give a three phase winding with a twelve phase connection to the twenty four pulse converter. Theoretical and experimental assessments of the impact of these modifications and attachment of the compensator have shown that there is a slight reduction in the torque developed at a given slip and in the combined system efficiency. There is also an increase in the noise level, also a consequence of the harmonics. The stator leakage inductance gave inadequate coupling reactance between the converter and the effective voltage source, necessitating the use of external inductors in each of the twelve phases. The terminal power factor is fully controllable when the induction machine is used either as a motor or as a generator.

Excitation of higher harmonic gratings in AC-field biased photorefractive crystals

We analyze the nonlinear excitation of holographic gratings in a photorefractive crystal being subject to an alternating electric field and a stationary light interference pattern. The influence of the higher harmonics on the fundamental grating is illustrated for the case where a crystal of Bi12SiO20 is the recording medium. We analyze both the steady state and the transient consequences of the higher harmonic excitation.