Applied Mechanics and Materials Vol. 792

Abstract: The paper considers the study of the electromagnetic force (EMF) of a synchronous generator based on the three-phase induction machine. The stand includes: a frequency converter, an induction motor, a synchronous generator, a three-phase rectifier, an active load resistance, power protection and inclusion industrial electrical network. The study provides an analytical solution to one of the main objectives within theoretical foundations of electrical engineering, formulated so to reflect the decision making while designing new types of synchronous generators with permanent magnets.

Abstract: The article presents the comparative analysis of influence frequency regulated electric drive and current electric drive to harmonic structure of voltage of power grid. There was obtained the dependence of total harmonic distortion (THD) of curve on loading power for 2 types of valve converters. The effectiveness is shown in use of filter compensating device, connected at low side of converting transformer. There were defined the ranges of filter adjusting for improving THD of voltage curve. The described solutions are performed by the structural modeling method of Simulink packet in Matlab environment.

Abstract: It has been proven that the introduction of the systems for continuous control of the equipment technical state is a necessary requirement of the modern maintenance of the critical equipment. The paper proposes the list of the processing facilities applied within the development systems for technical state control. The task of development of the system for recording, storing and displaying oscillographs of the automated electric drives of the wide-strip hot-rolling mill has been defined. The paper offers the analysis of the recording system based on the remote I/O controllers and the system with distributed industrial computers. The most informative-significant signals are listed. The network topology of the decentralized system implemented at the 2,500 mm wide-strip hot-rolling mill of OJSC Magnitogorsk Iron and Steel Works is suggested. Oscillographs of the main coordinates of the mill's electric drives obtained by means of the introduced system are provided.

Abstract: A thermal mathematical model of the induction traction motor was developed. The thermal model calculates the motor node temperatures with minimum number of input parameters. It can be applied as a thermal control condition system of electric traction motors during the operation. The adequacy testing results of the mathematical model in ELCUT were presented. Also, the comparison of mathematical model information and the results of experimental researches were submitted.

Abstract: This paper introduces researching results of hybrid synchronous motor rotor permanent-magnet part magnets’ magnetization influence on its starting torque. The magnetic field analysis is made in reluctance synchronous motor and synchronous permanent-magnet motor, as main parts of the hybrid motor.

Abstract: This work presents the test results of the enameled winding wires, characterizing an insulation mechanical strength. The standard and original test methods were used. It should be noted that the existing standard test methods do not estimate enamel insulation resistance to the mechanical loads authentically. Note that the estimation of wire mechanical resistance can be done by the determination of the number of defects in the enamel insulation. The results of tests for wires with various types of insulation are presented.

Abstract: Improvement of calculation accuracy of dynamical processes in an inductor with the massive magnetic core is an actual problem. The mathematical model of these processes consists of electrical and magnetic balance differential equations derived for the non-linear inductor generalized equivalent circuit. The main attention is focused on the non-linear inductor dynamical model schematic implementation, and development of a robust algorithm to analyze electromagnetic processes in non-stationary modes by means of structured modeling in Matlab Simulink.

Abstract: Today, one of the most common ways to control smooth starting and stopping of the induction motors are soft-start system. To ensure such control method the use of closed-speed asynchronous electric drive of TVR-IM type is required. Using real speed sensors is undesirable due to a number of inconveniences exploitation of the drive. The use of the observer based on a neural network is more convenient than the use of the real sensors. Its advantages are robustness, high generalizing properties, lack of requirements to the motor parameters, the relative ease of creation. This article presents the research and selection of the best learning algorithm of the neuroemulator angular velocity of the electric drive of TVR-IM type. There were investigated such learning algorithms as gradient descent back propagation, gradient descent with momentum back propagation, algorithm of Levenberg – Marquardt, scaled conjugate gradient back propagation (SCG). The input parameters of the neuroemulator were the pre treatment signals from the real sensors the stator current and the stator voltage and their delay, as well as a feedback signal from the estimated speed with delay. A comparative analysis of learning algorithms was performed on a simulation model of asynchronous electric drive implemented in software MATLAB Simulink, when the electric drive was running in dynamic mode. The simulation results demonstrate that the best method of learning is algorithm of Levenberg – Marquardt.

Abstract: The paper describes the determination method of quasi-reactive power for synchronous generator turn-to-turn short circuit diagnostics. A proposed method allows to determine the relation between the exciting current and quasi-reactive power at the generator leading to a high probability. This relation is the basis of the determination method of turn-to-turn short circuit availability and its severity.