Comparison of the design features of an electromechanical converter with a discrete secondary part with the classical installation options

In the present article, devices with a discrete secondary part are considered, which act as means of intensifying many technological processes of mixing and dispersing materials. In the classic version, the device has a number of disadvantages. To eliminate the shortcomings, the design of an electromechanical converter with a discrete secondary part was developed, which differs from the classical version by a magnetic system capable of implementing the process of controlling the movement of a large set of ferromagnetic elements along a pre-developed trajectory.

Innovative electrical engineering developed for the transport industry by the Emperor Alexander I Petersburg State Transport University

Objective: To familiarize the general scientific community with the latest electrotechnical innovative developments for the transport industry, carried out by the scientists of the Emperor Alexander I Petersburg State Transport University in the period from 2000 to 2021. Methods: We used the methods of calculation of electromagnetic fields and circuits, mathematical analysis, mathematical physics and numerical methods in the development of the described devices and systems. Results: 101 We developed a pipeline high-speed magnetolevitation transport system with vehicle movement in a rarefied atmosphere, a series of pantograph pantographs for heavy-loaded and high-speed trains using solid lubricants and a contactless method of transmitting electrical energy, a plasma device for fine cleaning of circuit boards for microcircuits, a device for creating a comfortable climate in office premises, electrohydroimpulse installations designed for loosening frozen coal in gondola cars in winter, shock tests of wagons, escalators and travalators using linear electric motors, high-speed electric switches-breakers, heat generators based on an electromechanical converter with the functions of a heater and pump, a wagon generator with a forced excitation system, a pulse voltage generator, allowing to measure the pulse resistance of the grounding conductors of the contact network supports, a complex of installations for various purposes using ozone technologies, a system for laser monitoring of the integrity of tanks, a device for diagnosing the degree of corrosion of the fittings of contact supports, an electrohydroimpulse installation for impact welding, treatment plants, technology for recycling car tires, security systems of the main trackbed. Practical importance: The use of the described developments will increase energy efficiency, energy saving and safety of production processes in transport

LOW-FREQUENCY ELECTROMECHANICAL VIBRATION CONVERTER BASED ON LEVITATION EFFECT

At present, one of the urgent problems in the energy and industry is to improve the reliability of the operation of various equipment. An effective method for increasing the reliability of equipment is diagnosing the state of machines and predicting their performance. Vibration control methods are widely used to diagnose rotary rotating machines. By the nature of the vibration process of the machine, it is possible to determine the degree of wear and, accordingly, the technical condition of the machines. In measuring technology for diagnostics of low-speed equipment with rotation frequencies of a unit of Hz, for example, hydroelectric generators of hydroelectric power plants, inertial electromechanical converters are used. The latest developments of such converters use an electromagnetic suspension with parametric feedback, which allows you to control the rigidity of the oscillatory system. However, for centering the moving part in electromechanical converters, flexible guides are used, which are sources of dry friction, which complicates the simulation of measurement processes and limits the sensitivity threshold to a minimum. In addition, flexible guides limit the frequency range of the converters. Currently, the most promising direction for solving this problem is the levitation effect, which allows you to completely exclude mechanical contact and, accordingly, reduce the sensitivity threshold of the transducer. From the analysis of literary sources, it follows that there are relatively few publications in this area. The proposed article provides an analysis of existing converters, on the basis of which a converter with improved characteristics, a measuring converter, is proposed. The proposed electromechanical converter has improved metrological characteristics and therefore can control and diagnose equipment in various fields of human activity. This problem is especially relevant in the hydropower industry.

INFLUENCE OF AN EXCITATION SOURCE ON THE POWER INDICATORS OF A LINEAR PULSE ELECTROMECHANICAL CONVERTER OF INDUCTION TYPE

The purpose of the article is to evaluate the efficiency of an induction-type linear pulse electromechanical converter (LPEC) when operating in shock-power mode and excitation from an alternating voltage source (AVS) in comparison with excitation from a capacitive energy storage (CES). A mathematical model of an induction-type LPEC has been developed both when excited by a unipolar pulse from a CES and from an AVS using lumped parameters of the windings, which takes into account the interrelated electromagnetic, mechanical and thermal processes. It has been found that when the LPEC is excited from the AVS with a voltage frequency of 50 Hz, the electrodynamic force takes on a periodic decaying character with a significant prevalence of positive components of forces over negative ones. The maximum value of the force is much less, and the value of its impulse is much greater than in the LPEC, excited from the CES. With an increase in the frequency of the AVS voltage from 50 to 150 Hz, the highest value of the current density of the inductor winding decreases, and in the armature winding it increases. The greatest values of force and impulse of force are realized at a voltage frequency of 150 Hz. With an increase in the AVS frequency, the relative indicator of the efficiency of the LPEC increases. References 15, figures 4.

INVESTIGATION OF THE TEMPERATURE FACTORS INFLUENCE ON OPERATING SAFETY THE SUBMERSIBLE ELECTROMECHANICAL CONVERTER

The article presents a mathematical model of the thermal field for determining the values of temperatures during the submersible electromechanical converter operation. The influence of obtained temperature values on the safety and reliability of the submersible electromechanical converter is analyzed. In a submersible electromechanical converter the windings temperature has great importance. On the one hand, the windings temperature must be such as to transfer a sufficient amount of heat to the viscous loading environment for its processing (movement, transportation, etc.) to begin. On the other hand, the windings temperature must not exceed the limit values for the corresponding insulation class, since this can cause an emergency (fire, short circuit, etc.) The obtained results shows, that temperature on the surface of rotor's cylinders reaches 135 ° C, which provides rapid heating of a viscous substance, and therefore high performance of the pumping process. In this work, the bitumen BND 200/300 was used as the loading and cooling environment. The flash point of this brand of bitumen is 220 ° C and characterizes the degree of flammability of bitumen when it heated. Bitumen does not reach the maximum allowable temperature as a result of heating by means of submersible electromechanical converter that creates a safe temperature corridor in a technological chain at its processing. The temperature of the outer surface of the submersible electromechanical converter, with which the service technical staff may have a contact, does not exceed 20 ° C (Fig. 3), which is completely safe and does not endanger the workers health or life. Also, the obtained temperatures values are within the permissible limits of the heat resistance class of a winding electrical insulating material (H - 180 ° C), which also contributes to the safe submersible electromechanical converter operation.

EXCITATION OF A PULSE ELECTROMECHANICAL CONVERTER OF ELECTRODYNAMIC TYPE FROM A TWO-SECTION CAPACITOR ENERGY STORAGE

A mathematical model of a pulsed electromechanical converter (PEC) of electrodynamic type has been developed, in which the solutions of the equations are presented in a recurrent form, which, when numerically implemented, allows taking into account the interrelated electrical, magnetic, mechanical and thermal processes and their nonlinear parameters. While maintaining the total energy of the pulsed source, the influence of the distribution of energy between the two sections of the capacitive energy storage (CES) and the voltage at which the additional section of the CES is connected was established. When operating in an accelerating mode, the largest amplitude of electrodynamic forces (EDF) and maximum speed occur in the basic version of the PEC, which is excited only from the main section of the CES, and the most effective is the PEC with the smallest capacity of the main section of the CES, and its maximum value is 2.61 higher than for the basic version of the PEC. When operating in the shock-power mode, compared with the basic version of the PEC, the amplitude of the EDF decreases. The most effective is the PEC with the smallest capacity of the main section of the CES, and its maximum value is 5.17 higher than that of the basic version of the PEC. Experimental studies of the PEC in the shock-power mode established that the oscillograms of the voltage of the CES and the current of the PEC correspond to the calculated characteristics, and their main indicators are consistent with each other with an accuracy of 5-7%. References 16, figures 6.

Features of excitation of a linear electromechanical converter of induction type from an AC source

Purpose. The purpose of the article is to establish the basic laws of operation of induction-type linear electromechanical converter (LEMС) during operation in high-speed and shock-power modes and excitation from an AC source of increased frequency. Methodology. With the help of a mathematical model, the regularities of the course of processes in a LEMС, excited from an AC source, were established when working with shock-power and high-speed modes. The solutions of the equations of the mathematical model, which describe interrelated electrical, magnetic, mechanical and thermal processes, are presented in a recurrent form. Results. It was found that when the LEMC operates in the shock-power mode, the maximum value of the current in the inductor winding occurs in the first half-period, and in the inhibited armature winding in the second half-period. The electrodynamic force changes at twice the frequency, taking on both positive and negative values. Since the positive values exceed the negative ones, the magnitude of the impulse of the electrodynamic force increases with each period of the force. Depending on the initial voltage phase, the relative change in the magnitude of the force impulse is 1.5 %. It was found that when the LEMC operates in high-speed mode, the current in the inductor winding in the first half-period has the greatest value, but after several periods it takes on a steady state. The temperature rise of the inductor winding increases with the time of connection to the AC source, and the temperature rise of the armature winding has the nature of saturation. The electrodynamic force has an oscillatory character with strong damping and a significant predominance of the positive component. Depending on the initial phase of the voltage, the relative change in the maximum speed of the armature winding is 2.5 %. Originality. For the first time, a mathematical model of the LEMC, excited from an AC source, was developed, the solutions of the equations of which describe the interrelated electrical, magnetic, mechanical and thermal processes. For the first time, the regularities of the course of processes in LEMC were established when working with shock-power and high-speed modes. Practical value. The characteristics of LEMC are obtained, which determine the efficiency of work in shock-power and high-speed modes. It is shown that the initial voltage phase has no significant effect on the power, high-speed thermal performance of the converter excited from an alternating current source.

Modeling of thermal process in the energy system “Electrical network - asynchronous motor”

The paper discusses the influence of low-quality electricity on the temperature modes of operation of an asynchronous motor. In the course of experimental and analytical studies, the heat transfer coefficients and heat capacity of a particular electromechanical converter were determined. Experimental and analytical dependences of temperature changes of an asynchronous motor on time are given when it is connected to a supply voltage with different coefficients of sinusoidal distortion and negative sequence. The resulting model is tested for its adequacy to the real process and can be used as an element in the energy-economic model of an asynchronous motor to assess its uptime. This model that can be useful for simulation of thermal processes in asynchronous motors and optimising these devices for increasing the reliability.

Determination of the Electromagnetic Processes Frequency Period in Emergency Operation Modes of Low-Power Multiphase AC Converter-Fed Motors

Increasing requirements for the reliability indicators of technical systems lead to the need to apply new approaches to the design of electric machines and electric drives as an electrical complex, one of which is a systematic approach. To provide a set of increased reliability indicators, it is proposed to use multiphase AC converter-fed motors that differ in structural and algorithmic redundancy It is shown in order to implement variants of AC converter-fed motor circuit, in addition to reliability indicators, a quantitative assessment of its energy capabilities in normal and emergency operating modes is necessary. The most important stage of the practical implementation of the numerical process in the quantitative assessment of energy capabilities is to determine the period of repeatability of electromagnetic processes. The main issues of determining the period of repeatability of quasi-steady-state electromagnetic processes of an electromechanical energy converter of low-power multiphase AC converter-fed motors in the design of systems of increased reliability are considered. This made it possible to implement the numerical solution of systems of differential equations describing the physical processes in AC converter-fed motors with a variable structure of the electromechanical converter in normal and emergency operating modes.