Showing papers on "Prime mover published in 1993"

Starter/generator system with variable-frequency exciter control

Abstract: A control for a brushless generator is operable in a starting mode of operation to convert electrical power into motive power for starting a prime mover. The control applies AC power to an exciter field winding at a first frequency at the initiation of a start sequence and thereafter decreases the frequency of the power applied to the exciter field winding during the start sequence.

Engine starting system utilizing multiple controlled acceleration rates

Abstract: A control for operating an electromagnetic machine in a starting mode of operation wherein the main armature winding of the machine receives electrical power from a controllable power source during the starting mode of operation, comprises a circuit for detecting a magnitude of a parameter of power applied to the main armature winding relative to a stationary frame of reference, a position sensor for detecting rotor position of the electromagnetic machine, a converter responsive to angular position indication for converting the detected parameter magnitude into field and torque producing components relative to a rotating frame of reference, and a circuit responsive to the field and torque producing components for controlling the power source during operation in the starting mode. This control includes an igniter for igniting a prime mover. Further, the control is operable during a first phase prior to ignition of the prime mover for causing the electromagnetic machine to provide motive power to the prime mover so as to accelerate the prime mover at a first predetermined rate, is operable during a second phase subsequent to the first phase so as to accelerate the prime mover at a second predetermined rate, is operable during this second phase for providing fuel to the prime mover to facilitate ignition thereof, and is operable during a third phase subsequent to the ignition of the prime mover so as to accelerate the prime mover at a third predetermined rate to a self-sustaining speed.

A technique for the steady-state analysis of a self-excited induction generator with variable speed

Abstract: A method to analyze the steady-state open loop behaviour of a self-excited induction generator with an unregulated prime mover is presented. The proposed method needs little mathematical effort and does not require an assumption about the generator speed. The proposed approach based on nodal analysis allows one to use arbitrary functions for the torque-speed characteristic of the prime mover and for the saturation of the magnetizing inductance without complicating the solution process. It always leads to a single equation for the frequency. An example is presented demonstrating the advantages of the proposed method. The analytical results are verified by measurements. >

A novel self-exited self-regulated single phase induction generator. II. Experimental investigation

Abstract: Part I of this paper presents the basic system, theoretical modelling and typical test results of a novel self-excited self regulated induction generator. In this part, the results of a detailed experimental investigation are presented to assess its suitability for practical applications. The steady state performance of the self-excited single phase induction generator, maintaining the terminal voltage within a close range is investigated under realistic loading conditions in the laboratory. Detailed experimental results are presented and discussed. Necessary tests to obtain machine parameters for theoretical modelling are also developed and relevant results of the prototype presented. The effects of series and shunt capacitors, prime mover speed, load and load power factor are investigated. It has been shown to exhibit a better voltage waveform as compared to commercially available sets. The experimental results confirm that this new generating system can be favourably employed for use as a small portable generator driven by nearly constant speed prime movers such as oil engines or hydro turbines. >

Controlled starting method for a gas turbine engine

Abstract: A method of controllably starting a prime mover, such as a gas turbine engine for an aircraft, in which the prime mover is coupled to a synchronous machine operable in a generating mode in which the synchronous machine converts motive power generated by the prime mover into electrical power and in a starting mode in which the synchronous machine provides motive power to the prime mover to accelerate the prime mover to self-sustaining speed includes three controlled phases: a pre-ignition phase, an ignition phase, and a torque augmentation phase. During each phase the prime mover is accelerated at a predetermined rate. When the motive power provided by the synchronous machine falls below a predetermined level, its operation is converted from its starting mode to its generating mode.

Analysis of series-connected wound-rotor self-excited induction generator

Abstract: The paper presents theoretical and experimental investigations for steady-state performance of a three-phase wound-rotor series-connected self-excited induction generator (SCSEIG). This type of generator can be realised by series connection of stator and rotor windings of a slip-ring type induction machine. Self excitation may occur when a suitable capacitor bank is connected across the machine terminals. The generator produces an output voltage with a frequency of half the rotor electrical angular frequency and independent of the load conditions provided that the prime mover speed is kept constant. The well known generalised machine theory has been employed with a proper transformation, resulting in a hypothetical equivalent saliency, which produces periodically time-varying inductances needed for such generators (via the mutual coupling between rotor and stator windings). Analysis is achieved by considering saturation effects on both axes (d and q) and theoretical results were found to agree well with corresponding experimental values

Decentralized excitation control for an electrical power utility system

Abstract: A power utility system includes a generator driven by a prime mover in response to a mechanical input power and an excitation to provide an electrical output power. The excitation of the generator is controlled in response to an estimated equilibrium rotor angle. The estimation of the rotor angle is based on purely local measurements. This estimated rotor angle is used in conjunction with a feedback linearizing controller to provide field excitation control of the generator. The rotor angle reference signal is also used to provide a rotor angle error signal to a power system stabilizer which is modified to operate on the basis of an angle error rather than a speed or frequency error.

Planetary steering system for a skid-steered vehicle

Abstract: The present invention is directed to a planetary steering system for a skid steered vehicle. A prime mover directs rotational motion through right and left drive shafts having planetary carriers with planet gears. The planet gears of the right and left planetary carriers rotate around a right and left sun gears that are coupled to right and left hydraulic steering motors. The planet gears rotate in right and left ring gears that are coupled to the right and left drive wheels of the vehicle. By rotating the motors the speed of the drive wheels can be independently controlled.

Mounting apparatus for a bridge of a trenching machine

Abstract: A trenching bridge mounting interface for a trenching machine that is adjustable to alter the effective length of a fixed length bridge so as to accommodate trenching bars of different lengths. The interface includes a prime mover mounting structure that is releasably secured to the prime mover of the trenching machine and a bridge mounting structure attached to the fixed length bridge. The effective length of the bridge is adjusted between a short length and a long length by reversing of the prime mover mounting structure.

Method of improving temperature uniformity of a space conditioned by a refrigeration unit

Abstract: A method of operating a refrigeration unit to improve the uniformity of temperature distribution in a conditioned space, with the refrigeration unit including a refrigerant compressor and an evaporator fan driven at a selectable one of high and low operating speeds by a prime mover arrangement. The method includes the step of periodically operating the compressor and evaporator fan at the higher of the two operating speeds, notwithstanding a set point temperature control algorithm calling for operation of the compressor at the lower of the two speeds. When the refrigeration unit is operating in a continuous mode, the value of a constant entered into an operating program by the user determines the minimum number of minutes of each hour the prime mover should be forced to operate in the higher speed mode. When the refrigeration unit is operating in a cycling start-stop mode, the value of the constant entered into the operating program by the user determines which operating cycles are to be performed with the prime mover in the high speed mode, notwithstanding a set point temperature control algorithm calling for the low speed mode.

Vibratory cable plow assembly

Abstract: A vibratory cable plow assembly including a frame assembly for connecting a plow blade to a frame of a prime mover. The frame assembly supports a vibrating mechanism or shaker that is adapted to impart vibratory movements to the plow blade. The frame assembly includes a lower support that extends rearwardly from its pivotal connection to the frame of the prime mover. The lower support mounts a blade supporting frame for rocking movement about a generally horizontal pivot mechanism. The blade supporting frame is mounted toward a distal end of the lower support intermediate its free ends and has the plow blade attached to a free end thereof. The vibratory mechanism is mounted on the blade supporting frame. An extendable/retractable driver extends about the lower support and is pivotally connected between the frame of the prime mover and the other free end of the blade supporting frame. An elastomeric bearing assembly isolates the blade supporting frame from transferring vibrations to the prime mover. A mounting promotes attachment of the frame assembly to the frame of the prime mover and facilitates horizontal movement of the plow blade relative to the frame of the prime mover.

Continuously-variable-ratio transmission having an improved starting arrangement

Abstract: A continuously-variable-ratio transmission ("CVT"), especially of the toroidal-race rolling-traction type, in which the prime mover is connected to the ratio-varying component ("variator") by a torque converter or other starting device capable of slip. The CVT output is connected both to the variator output and also, by way of fixed ratio gearing and a one-way clutch, to the output of the starting device. At low speeds drive is transmitted from prime mover to the CVT output by way of the fixed ratio gearing in both forwards and reverse. In forward drive, as the speed of the variator output rises, operation of the one-way clutch causes the drive transmission path to change from the fixed ratio gearing to the variator output once the speed of the latter exceeds the former. Where the variator is of the toroidal-race type, further one-way clutch means may be included to ensure that the fixed ratio gearing components can rotate in one direction only, thus preventing them from imposing reverse rotation upon the essentially unidirectional variator components.

Adaptive control of speed and equivalence ratio dynamics of a diesel driven power-plant

Abstract: A method of modeling, involving approximation of dead-times, is presented for diesel driven power prime-movers. The resulting predictive adaptive control scheme is compared to a conventional PI scheme on the basis of common disturbances encountered by a practical prime-mover. It is found that the adaptive scheme achieves significant improvement despite the nonlinearities introduced by turbocharger operation. It is observed in general that adaptive schemes, such as the one described, affect the prime-mover dynamics in essentially two ways. First, the engine fuel-flow response is improved by better control of the actuator. Secondly, by indirectly controlling the exhaust energy of the plant, the turbocharger air-dynamics is made faster, leading to better dynamic fuel/air ratio. The overall effect is good response of the prime-mover speed notwithstanding the fact that the diesel prime-mover is a low inertia structure and that the system parameters suffer from various nonlinear variations. >

Motor arrangement for roller skater

Abstract: A motor arrangement for a roller skater comprising a frame provided with a prime mover, a pair of tires mounted on a transversal axle connected to the frame, a drive bar integral with such frame and carrying at the fore end the motor controls, and a thrust cross-bar secured to the drive bar and pushing the body of the user seizing such drive bar.

Propulsion powered electric guns-a comparison of power system architectures

Abstract: Alternative power system architectures and interface technologies for driving high-energy pulsed loads from the propulsion equipment of naval surface combatants are compared. Gas turbine mechanical and gas turbine integrated electric drive propulsion trains are considered as prime power sources. Focus is on the energy path between the ship's prime power and the pulsed load, comparing system candidates on a size, weight, and component cost basis. A capacitor-based pulse forming network (PFN) supplying an electrothermal chemical gun is utilized as the common load for all configurations. Results indicate that dedicated auxiliary generators driven from propulsion gas turbine engines are the preferred method of powering electric gun PFNs from ship drive-train equipment. Auxiliary generator-based systems are compact and lightweight over a wide power range, are equally attractive with both electric and mechanical drive trains, and demonstrate retrofit potential to the current fleet. >

Rotating induction generator adapted to be driven by a prime mover for generating electrical power

Abstract: A rotary induction generator having a stator with stator windings (21) defining a three-phase stator and a rotor mounted for rotation therein and having wound thereon three rotor windings (22) defining a three-phase rotor and having resistive-reactive means (23, 24, 26) connected to said secondary windings (22) to increase the efficiency of said generator and limit the power output to the capacity of the generator over a wide range of speeds; and the method for load limiting electric power generation with rotary induction generators wherein the generator can run at variable speeds while maintaining the frequency of the line connected thereto over a wide range of prime mover speeds whereby the excess kilowatt output is limited by the circuit employing a first circuit of three sets of resistance, inductance and capacitance means (23, 24, 26) connected in series from each leg of a wye or delta configuration, and wherein each of said sets is connected in parallel with a separate set of resistors (27) to complete the circuit therein and assist in controlling the maximum point in kilowatts.

Power transmission for coupling a prime mover to a vehicle

Abstract: A power transmission unit for coupling a prime mover to a vehicle, in particular a bicycle. The unit has a clutch assembly, a gear train, and a freewheel mechanism. The output shaft of the prime mover is connected to the input side of the clutch assembly. The output of the clutch assembly is connected to the input side of the gear train. The output side of the gear train is connected to the freewheel mechanism. The freewheel mechanism is connected to a first sprocket wheel. The first sprocket wheel and a second sprocket wheel are mounted together on a common freewheel which in turn is mounted on the crankshaft of the bicycle. The second sprocket wheel is connected to the rear wheel of the bicycle. In the absence of power from the prime mover, the bicycle may be used in a conventional manner. When in use, the prime mover drives the rear wheel of the bicycle via the clutch assembly, gear train, freewheel mechanism, sprocket wheels and the rear wheel.

Pinch valve with adjustable reaction member

Abstract: A pinch valve has a length of flexible tubing (42), preferably comprising two concentric tubes. The tubing is supported on an adjustable reaction member (43) below a cam follower (39) which cooperates with a cam (38). The cam (38) is driven by the prime mover (24) and the adjustable member (43) allows use of different sizes of flexible tubing. The prime mover is preferably an electric motor which drives the cam via a gear train. The valve may comprise more than one length of tubing which are pinched simultaneously or sequentially.

Prime mover driven compressor/chiller with motor on common shaft for large cooling systems

Abstract: A method of driving a large cooling system having a compressor operating as a chiller driven by a prime mover, such as a gas turbine, reciprocating engine or steam turbine, in conjunction with an electric motor/generator coaxially arranged on a common shaft with the other units, so that as the ambient temperature rises and the power needed to produce the cooling output increases, and as there is a corresponding drop in power output if the prime mover is a gas turbine or condensing steam turbine, the required additional driving power is supplied by the motor. Conversely, as the ambient temperature drops and required cooling power lessens, the electric motor operates as a generator to convert the excess prime mover power to electrical power.

A NOVEL SELF-EXCITED SELF-REGULATED SINGLE PHASE INDUCTION GENERATOR Part-ll : Experimental Investigation

Abstract: Part I of this paper presents the basic system, theoretical modelling ancl typical test results of a novel Self-Excited Self Regulated Induction Generator. In this part the results of a detailed experimental Investigation are presented to asses its suitability for practical applications. The steady state performance of the self-excited single phse induction generator (SEIG), maintaining the terminal voltage within a close range Is investigated under realistic loading conditions in ithe laboratory. Detailed experimental results are presented and discussed. Necessary tests to obtain machine parameters for theoretical modelling are also developed and relevant results of the prototype presented. The effects of series and shunt capacitors, prime mover speed, load and load power factor are investigated. It has been shown to exhibit better voltage waveform as compared to commercialiy available sets. The experimental results confirm that this new generating system can be favourably employed for use as a small portable generator driven by nearly constant speed prime movers such as oil engines or Hydro Turbines.

Prime mover rotational speed control device for hydraulic construction machine

Abstract: PURPOSE:To improve operability and reduce noise and fuel consumption in a hydraulic construction machine by detecting acting direction of a hydraulic actuator, and deciding the rotational speed correcting value of a prime mover for driving the hydraulic actuator on the basis of the acting direction and load condition. CONSTITUTION:A hydraulic actuator is driven by oil discharged from a variable capacity oil pressure pump driven by a prime mover. Rotational speed of the prime mover is controlled by a pulse motor 28. In this case, in a control unit 80, a target rotational speed is calculated by a calculating unit 81 on the basis of the displacement value of a rotational speed setting device 57. A rotational speed correcting value is calculated by a calculating unit 82 on the basis of each detection signal from a pressure sensor 52 and each pilot pressure sensor. The rotational correcting value is further inputted into an adding unit 87 through a selecting switch 89 interlocked to a selecting switch operating unit 58, and a target rotational speed command value is calculated. The target rotational speed command value is compared with the detection value of a potentiometer 55, and the pulse motor 28 is controlled.

Experimental heat exchanger performance in a thermoacoustic prime mover

Abstract: The effectiveness of heat transfer between the thermoacoustic stack and a typical copper fin heat exchanger is determined by the detailed gas motion and thermal diffusion, and the fin geometry. This effectiveness depends strongly on acoustic amplitude and heat load, as does the ability of the copper to conduct the heat. These and other nonlinear effects contribute to limiting the amplitude of a prime mover. A modular prime mover experiment has been built so that the limiting amplitude can be measured with a variety of heat exchanger geometries, with the goal of finding the best geometry. The liquid nitrogen temperature experiment uses a heavier gas, such as neon, at a low pressure in order to minimize the heat load, and the temperature defects associated with copper conduction, while allowing large Mach numbers and gas particle displacements. In preliminary measurements, peak pressure amplitudes are in access of 20% of the mean pressure and the peak‐to‐peak acoustic displacements are comparable to the sta...

Apparatus for inserting netting into a ground surface and method for accomplishing same

Abstract: An apparatus and method for inserting netting into a ground surface is provided. The apparatus includes a frame adapted to be connected to a prime mover and having a roller transverse to the direction of normal movement of the frame. The roller has spaced annular extensions thereabout, the roller limiting the depth of entry into the ground of the extensions to the radius of the annulus formed by the extensions. The apparatus further includes a vibrator associated with the roller causing the roller to vibrate. The extensions able to effectively fluidize the ground surface so that the netting fed to the underside of the roller can be located in or under the ground surface by pressure from the extensions while the ground is fluidized. The apparatus may be used with a prime mover by mounting the apparatus on a rear portion thereof and by including a material delivery device located on the prime mover.

Load transport vehicles

Abstract: A transport unit (100) is designed to be towed behind a prime mover (170) to enable loads to be transported from site to site, over even rough terrain. The unit (100) has wheels (114) journalled on axles (113) on trailing arms (112) provided with springs (116) (or rocker arms) to share the load. The load (e.g. containers, pallets, tanks) is engaged by forks (125) on a carrier frame (124), raised or lowered by a hydraulic ram. As the unit (100) straddles the load with its U-shaped chassis, and the load may be transported at a low height, the unit (100) is very stable. Lights (16), mud flaps (161), brakes and the like enable the unit (100) to be towed on public roads.

Extended Transient-Midterm Stability Program: Version 3.0. Volume 1, Executive summary: Final report

Abstract: This report details the techniques employed in EPRI`s Extended Transient Midterm Stability Program (ETMSP) version 3.0. The work on this program commenced in 1988, and was completed in 1992. The program is radically different from the original version of ETMSP, version 1.0. The code is completely new, based on Ontario Hydro`s SIMU rather than ETMSP version 1.0. ETMSP has many advanced features, both in terms of modelling and solution capability and in user friendliness. It is fast and economical in computing facilities: it is up to 16 times faster than ETMSP version 1.0, and its system size limit is 6 times greater with only twice the computer storage requirement. ETMSP version 3.0 has both explicit and implicit differential equation solution methods. It models. Its model complement includes: Detailed generators: Excitation systems, Prime Mover/Governor systems; Two terminal and multi-terminal HVDC links; Dynamic and static loads; Under load tap changers; Flexible ac transmission systems (FACTS); and Relays. User defined models are available for generator controls, FACTS and HVDC controls. Input of both power flow and dynamic data can be in a variety of commonly used formats which are compatible with other EPRI programs which form the Power System Analysis Package (PSAPAC).

Fuel supply system and method for coal-fired prime mover

Abstract: A coal-fired gas turbine engine is provided with an on-site coal preparation and engine feeding arrangement. With this arrangement, relatively large dry particles of coal from an on-site coal supply are micro-pulverized and the resulting dry, micron-sized, coal particulates are conveyed by steam or air into the combustion chamber of the engine. Thermal energy introduced into the coal particulates during the micro-pulverizing step is substantially recovered since the so-heated coal particulates are fed directly from the micro-pulverizer into the combustion chamber.

Real-time test results with adaptive speed controllers for a diesel prime-mover

Abstract: Self-tuning adaptive control algorithms, that employ explicit dead-time identification techniques, have been discussed in the literature vis-a-vis the diesel-driven power prime-mover. Such algorithms are numerically intensive owing to the complicated identification algorithms. This paper discusses the implementation of the above mentioned algorithms on a Texas Instruments' DSP 320C30 based system. This digital signal processor has sufficient numerical capability to carry out all the real-time computations at sampling intervals of 10 ms. It can also perform well in the matters of speed measurement and control generation without any significant additional hardware. The results of real-time tests are compared with that obtained using the Woodward Governor Company's 701 prime-mover controller. >

Verfahren zum Abbremsen eines Fahrzeugs mit hydrostatischem Fahrantrieb und dafür vorgesehenes Fahrzeug

Abstract: During braking of a vehicle with a hydrostatic propulsion drive, an adjustable hydraulic motor (4) of the hydrostatic propulsion drive is adjusted in the direction of the greatest possible capacity and the kinetic energy of the vehicle is partly directed into a prime moved (1) and partly dissipated by pressure limiting valves (7, 8) in the closed working circuit of the hydrostatic drive. When the rotary speed of the prime mover (1) exceeds a limit during braking, the capacity setting reached by the hydraulic motor (4) is maintained, or the capacity is fixed at a defined level, until the rotary speed has dropped below the limit again. Then, the adjustment of the hydraulic motor (4) in the direction of the greatest possible capacity is continued. The capacity of the hydraulic motor (4) is set by a control pressure, and the control pressure is reduced to increase the capacity of the hydraulic motor (4) when braking. The control pressure is influenced when the rotary speed of the prime mover (1) exceeds the limit by a braking torque limiting device (B) operative according to the rotary speed of the prime mover (1). A modification (Fig 4) has a shuttle valve with two in lets in the motor control circuit. In a further modification (Fig 5), the spring side of a pressure limiting valve in the control circuit is additionally acted upon by pressure upstream of a measuring orifice.