Motor Rotation Frequency Research Articles

ЕЛЕКТРОМЕХАНІЧНІ ХАРАКТЕРИСТИКИ БЕЗКОНТАКТНОГО ДВИГУНА З ПОСТІЙНИМИ МАГНІТАМИ ПРИ ШИРОТНО-ІМПУЛЬСНОМУ ЖИВЛЕННІ

The paper is devoted to the study of the characteristics and operating modes of a brushless permanent magnet motor in the structure of an electric drive with a two-wire external power supply from a voltage source with pulse-width regulation. The dependences of the motor rotation frequency, the stator current effective value and the average value of the current in the DC link of the voltage inverter, as well as the dependences of the torque coefficient on the average value of the motor torque are given. The influence of the frequency of the pulse supply voltage on the operating modes of the motor is studied. The current and torque limitation modes of the motor in a system with a single-position relay controller and a fixed transistor shutdown interval former are studied. Ref. 12, fig. 16.

A measurement method for magnetic moment and magnetic declination of ferromagnetic samples based on rotating magnetic dipole

Abstract This paper presents a novel measurement method for detecting the magnetic properties of ferromagnetic materials. The proposed method uses a motor to rotate the ferromagnetic sample. At the same time, a triaxial magnetometer reads the magnetic field information, and the motor rotation frequency and the magnetometer sampling rate obtain the rotation angle information. A nonlinear optimization algorithm is applied to calculate the magnetic moment and magnetic declination angle of the sample. The effectiveness of the method is proved by numerical simulation and experimental measurement. Our results indicate that the proposed method offers several advantages, including its ease of deployment, simplicity of operation, high accuracy, and robustness. It provides a feasible solution for laboratory-based magnetic moment measurements and rapidly detecting magnetic moments in industrial settings.

Resonance analysis of fan blade design using Finite Element Method

Fan motors move liquids, such as air, in the gas phase from one place to another. The frequency of the fan blades, which are the main components of the fan motor, can vary. It is crucial to know the frequencies of each fan blade to avoid design failures caused by resonance. This research analyzes the effect of differences in the angle and number of blades on the natural frequency of the fan to avoid resonance with the motor rotation frequency. Modeling and simulation using the finite element method in the Solidworks application are used to determine the natural frequencies of the fan. Fans come in various configurations, with blades ranging from two to four, and blade pitch can be 25°, 30°, or 40°. Variations in the number of fan blades and changes in blade pitch show that the low mode shape does not affect the natural frequency, while the high mode has a negligible effect. The natural frequency of fan blades 2, 3, and 4 exhibits variations when operated with motors running at 25, 35, or 50 Hz. The findings imply that the fan blades' inherent frequency does not align closely with the motor rotational frequency, indicating that the design is safe.

Study and Analysis of a Multilayer Multipair Electret-Based Thin-Film Mechanical Antenna

Very low-frequency (VLF) and ultralow-frequency (ULF) electromagnetic waves have the advantage of high penetration and low propagation loss in wireless communication systems and are mainly used for underwater and underground communications, as well as for earthquake and lightning forecasting. At present, VLF and ULF antennas are mostly bulky and require hundreds of antennas and more to be set up, which is costly and inefficient. In this paper, we propose to generate VLF and ULF signals by rotating a multilayer multipair electret thin-film electret driven by an excitation device, which improves the problem of low radiation efficiency of VLF and ULF signals and the large size of conventional low-frequency transmitting antennas. Based on a multilayer, multipair electret film mechanical antenna, a magnetic field propagation model is developed, and the relationship between the magnetic flux density mode and the number of layers of electret films, as well as the relationship between the antenna emission frequency and the motor rotation frequency and the number of pairs of electret films, is analyzed. The selection of a suitable model for practical situations based on conditions such as antenna size and propagation distance is illustrated. The research work is of great importance for guiding the design of mechanical antennas and optimizing antenna structures.

Mass transfer from the rotor to the stator for improving the speed of the piezoelectric motor based on centrifugal force.

To improve the speed of a piezoelectric motor based on centrifugal force, a method is proposed on the basis of mass transfer from the rotor to the stator. Multi-degree-of-freedom vibration models are established before and after mass transfer. A mass of 150g is transferred from the six-hole rotor to the stator. This process increases the rotation frequency of the rotor under the same friction loss and increases the energy fed into the rotor by the stator. The motor operates at a frequency close to the resonance frequency. The change in the initial phase with the operating frequency close to the resonance frequency is analyzed, and the phase adjustment device and the signal processing circuit are designed. Two prototypes, one with and one without mass transfer, are fabricated and measured. As the initial phase is adjusted from 0° to 75°, the motor rotation frequency gradually increases, approaching the resonant frequency of the motor. When the excitation voltage is 790 Vp-p, the speed of the piezoelectric motor with a mass transfer of 150g reaches 11 004 rpm, which is 89% faster than the speed of that without mass transfer.

Уравнения магнитоэлектрического вентильного двигателя при витковых замыканиях обмотки статора

The article considers the differential equations of a switched permanent magnet motor in which a short-circuit fault occurred in one or more turns in one of parallel stator winding branches. Owing to the occurred asymmetry of the phase quantities, symmetrical line-to-line voltages at the stator winding terminals are assumed. It is shown that turn-to-turn short-circuit faults give rise to non-sinusoidal and imbalanced phase currents and voltages at the nominal load torque on the shaft, and it should be noted that initially, a growth of the frequency and ratios of currents in the phases with an increase in the number of short-circuited turns are observed, after which the phase currents tend to decrease (with a continuing growth in the current through the short-circuited loop), and the rotor stalling occurs. The growth of motor rotation frequency and decrease of its overloading capacity take place due to a growth in the demagnetizing effect of armature reaction caused by the current through the short-circuited stator winding turns.

Resonance behavior of the system with a limited power supply having the Mises girder as absorber

Three-DOF system with a limited power supply (or non-ideal system) having the Mises girder as absorber is considered. Stationary resonance regimes of vibrations near stable equilibrium positions of the system are constructed in two approximations of the multiple scales method. Namely, vibrations near the resonance 1:1 between the motor rotation frequency and the linear sub-system frequency and vibrations near the resonance 1:1 between the motor and absorber frequencies are analyzed. This analysis near the first resonance is made as in supposition that elastic springs of the Mises girder are weak and have an order of the small parameter, as well as in supposition that these springs are not weak. It is obtained that the effective absorption of the elastic vibrations can be obtained in the second case. Additional numerical simulation permits to find regimes of absorption when it is possible to guarantee also the fast outcome from the first resonance region. The most appropriate for absorption and such outcome from the first resonance are vibrations near the second resonance and the snap-through motions.

DESIGNING AND DEVELOPMENT OF A DYNAMIC VIBRATION BALANCING MACHINE FOR INDUSTRIAL APPLICATIONS

There is a steadily growing demand for reliable, versatile measurement rotor balancing system which can be used to determine the machine unbalances behavior. The effect of these causes are the increase of vibration amplitudes, causing damage to elements of the machines, mainly in the bearings, reduce useful life time, and increase fatigue failure in machines. The industry requires that machines have to operate continuously, efficient maintenance philosophy, and reduce down time. Therefore, this research work has the main objective to design and develop a low cost rotor balancing measurement system for industrial applications. This research study was based on the ISO 1940-1 standard. The Solidworks software was used for the designing, structural stress, and modal analysis. It was also carried out and extensive numerical analysis with Finite Element Method (FEM), of the developed measurement system, in order to identify the structure resonance frequencies to avoid with the induction motor rotation frequency. For the simplicity, precision and robustness, the single plane four runs method for rotor balancing was selected. Finally, it was developed a rotor balancing measurement system. It showed the ability, and potential to use the developed equipment in industrial environment. Moreover, it has been shown that the measurement and the applied analysis method have worked accurate for unbalance detection and reduction of vibration levels from G13 to G2.

Control system of roll crushes in emergency situations

The system of emergency control of a roll crusher is developed, which allows the hardness of the crushed material to be evaluated indirectly estimating the current strength of the unit, or directly by swing of the deflecting the crusher jaw, and the pieces with the increased hardness to be recrushed, increasing compression, reducing the motor rotation frequency. This system reduces the number of emergencies and provides less downtime for equipment in the event of an accident than crushers using conventional safety elements: toggle plates and restraining spring or hydraulic fuses. Besides, this system is extensible, i.e. it does not interfere with the inclusion of additional devices (for example, mechanical breakers such as toggle plates), sensors (for example, angle protractor to improve the accuracy of measurements). With the combined use of direct and indirect evaluation of the crusher condition the accuracy and efficiency of the crusher control increases improving the reliability of a crushing unit as a whole.

Adjustment of the speed-torque characteristic of a synchronous thyratron motor

Control of a synchronous thyratron motor with phase advance, which is proportional to the motor rotation frequency, is theoretically substantiated in [1] to allow the linear speed-torque characteristic to be obtained.

Quantitative simulative method of sediment resuspension in Lake Taihu

由于风浪对浅水湖泊底泥的强烈扰动作用, 底泥再悬浮的生态效应研究成为目前国际研究热点之一。但方法的缺乏极大地限制了有关底泥再悬浮环境效应的深入研究。本研究应用一种新的沉积物再悬浮装置, 模拟了太湖南部长兜港水域不同风浪影响下悬浮物的垂向分布, 获得水柱总悬浮物量(T)与扰动频率(n)的定量关系:T=19.77×exp(n/2.61)-71.7。结合现场实测风情下的水柱总悬浮物量, 建立了室内水动力条件、水柱总悬浮物量和现场风情的定量关系。研究2004年10月至2005年10月太湖全年代表性小风、中风及大风与再悬浮装置的扰动频率对应关系, 估算了小风、中风和大风常规风情引起的总悬浮物量分别为159、230、425g/m²。结果表明, 模拟获得的太湖悬浮物垂向分布规律与现场状况较为接近, 是目前较为适用的浅水水体沉积物再悬浮模拟方法。;Concerns on ecological effects of sediment resuspension are on the rise because the sediments in shallow lakes are frequently disturbed by winds. However, few methods could be suitable for supporting its related study. In this paper, Y-shape apparatus for simulating sediment resuspension was used to study vertical distribution of suspended sediments in water column and their total suspended amounts driving by different wind speed in Chang-dougang Harbor, southern Lake Taihu. The results showed that the relationship between the total suspended amount of sediments in water column (T) and the motor rotation frequency(n) could be expressed byT=19.77 exp(n/2.61)-71.7. Based on the total suspended amounts in water column under field wind conditions, quantitative relationships were achieved among the simulated hydrodynamic conditions, the total suspended amounts of sediments and the field wind conditions. According to the correspondent frequency of motor rotation to field wind speed in Lake Taihu from October 2004 to October 2005, the total suspended amounts of sediments were estimated at 159, 230 and 425 g/m² for field light, moderate and strong winds, respectively. The estimated amounts, together with the vertical distribution of suspended sediments in water column, were consistent with those observed under field conditions. The Y-shape apparatus was thus recommended for use in studying the ecological effects of sediment resuspension in shallow aqueous system.