This paper provides a theoretical perspective on human factors and ergonomics (HFE), defined as a unique and independent discipline that focuses on the nature of human-artefact interactions, viewed from the unified perspective of the science, engineering, design, technology and management of human-compatible systems. Such systems include a variety of natural and artificial products, processes and living environments. The distinguishing features of the contemporary HFE discipline and profession are discussed and a concept of ergonomics literacy is proposed. An axiomatic approach to ergonomics design and a universal measure of system-human incompatibility are also introduced. It is concluded that the main focus of the HFE discipline in the 21st century will be the design and management of systems that satisfy human compatibility requirements.

Ergonomics and human factors: the paradigms for science, engineering, design, technology and management of human-compatible systems.

Challenges of future aircraft propulsion: A review of distributed propulsion technology and its potential application for the all electric commercial aircraft

A vernier motor is an unexcited inductor synchronous motor in which a small displacement of the rotor produces a large displacement of the axes of permeance. It runs at a slow speed as if it were geared down from the speed of the rotating field set up by the stator. To design a vernier motor is equivalent to designing a polyphase reluctance motor with an odd-shaped rotor so that the airgap permeance distribution is a displaced triangular wave.

Vernier Motor and Its Design

A new method to determine physical parameters of a synchronous generator based on an online measurement of the electrical power, terminal voltage, and field voltage, following a small perturbation of the field voltage, and the rotor angle at the same steady-state operating condition is described in this paper. A multivariable linear transfer function, identified using the sampled input-output data, is converted to the parameters of the Heffron-Phillips model. Using the relations of the Heffron-Phillips parameters with the physical parameters, the physical parameters are estimated. These estimated parameters are then used in a nonlinear structure to model the synchronous generator. Experimental results with the proposed method applied to a micromachine show good accuracy of the model and also show that the identified nonlinear model is valid at other operating conditions. At dramatically different operating conditions, however, to include the effects of unstructured nonlinearities such as magnetic saturation, the parameters of the nonlinear structure can be slightly adjusted for better performance.

Identification of physical parameters of a synchronous Generator from online measurements

An air vehicle incorporating a hybrid propulsion system. The system includes a gas turbine engine as a first motive power source, and one or more battery packs as a second motive power source. Through selective coupling to a DC electric motor that can in turn be connected to a bladed rotor or other lift-producing device, the motive sources provide differing ways in which an aircraft can operate. In one example, the gas turbine engine can provide operation for a majority of the flight envelope of the aircraft, while the battery packs can provide operation during such times when gas turbine-based motive power is unavailable or particularly disadvantageous. In another example, both sources of motive power may be decoupled from the bladed rotor such that the vehicle can operate as an autogyro.

Aircraft using turbo-electric hybrid propulsion system

Recent advances in the theory of synchronous machines have introduced a large number of new constants. The method of symmetrical components requires sequence reactances, and an accurate theory of transients requires transient and subtransient reactances and time constants. Most of the published discussion on the constants has been concerned with the application, rather than the calculation of values. In this paper, all of the most significant constants are calculated, except the subtransient time constant. A general method of calculation is discussed in which the reactances are accurately resolved into components. Comparisons of test and calculated values are given. The formulas for salient-pole machines and turbine generators are given in Appendixes A and B. The principle of superposition is applied to resolve accurately the reactances into components which can be readily calculated. The induced currents in the field and additional damping circuits are accounted for simply by applying the constant interlinkage theorem.

Calculation of Synchronous Machine Constants- Reactances and Time Constants Affecting Transient Characteristics

A marine propulson system is described that includes a gas turbine, an alternating current generator, a fixed pitch propeller, a synchronous motor and a frequency converter. The frequency converted is connected electrically between the generator and motor during starting and reversal procedures when the motor would normally have to operate as an induction motor. Means are provided to brake the system dynamically to speeds within the capacity of the frequency converter. At speeds within the frequency converter's design capacity, the motor can be operated synchronously while it is running at a speed below the minimum operating speed of the turbine and generator.

Marine propulsion system

A transient fundamental-frequency torque is shown to occur in the starting of all induction motors. For full-voltage starting on a general-purpose squirrel-cage motor, this torque may be as high as two or three times the pull-out torque. A consideration of such torques is particularly advisable for cases where induction motors are started and stopped frequently or continuously, since under such conditions mechanical failure of the motor or associated parts, gearing, couplings, etc., may occur if the stresses exceed the endurance limit of the material. A method of analysis is given for calculating the transient electrical torques acting in the case of a locked rotor; the results obtained by means of this analysis are compared with test data obtained on a special locked-rotor test setup. A method is also given for calculating shaft torque from the electrical torque in the usual application. Test results also indicate that this method is satisfactory for practical use.

Transient Starting Torques in Induction Motors

A wound rotor motor and a flywheel are provided on a shaft with speed control of the motor by frequency control on its secondary applied by means such as a cycloconverter that is responsive to pulsating load conditions on the system. Power flows from the flywheel into the system during periods of high load and into the flywheel during periods of low motoring load or a regenerative load. The invention permits use of equipment, such as large excavators, that have sharply varying loads in their duty cycles, in locations where there are small, otherwise inadequate, power systems.

Electrical apparatus with frequency controlled load compensation

Our invention relates primarily to the electrical propulsion of airplanes, and it will be described more particularly with reference to its application to airplanes, although it is to be understood that it is applicable to aircraft in general. The principal object of our invention is to convert...

Lee A Kilgore

Papers

Calculation of Synchronous Machine Constants- Reactances and Time Constants Affecting Transient Characteristics

Marine propulsion system

Transient Starting Torques in Induction Motors

Electrical apparatus with frequency controlled load compensation

Electrical airplane propulsion