Motor Load Research Articles

Pengaruh Perubahan Beban Terhadap Putaran dan Daya Masuk Motor Induksi Tiga Fasa (Aplikasi Pada Laboratorium Konversi Energi Listrik FT-UHN)

An electric motor is an electro-magnetic device that converts electrical energy into mechanical energy. This mechanical energy is used to, for example, rotate a pump impeller, fan or blower, drive a compressor, lift materials, etc. Electric motors are also used at home (mixers, electric drills, wind fans) and in industry. Electric motors are sometimes called the "workhorse" of industry because it is estimated that they use about 70% of the industry's total electrical load.
 And at this time the power from the power source, namely PLN (State Electricity Company) often changes in voltage. Therefore, it is necessary to know by calculating the rotation and input power which is influenced by changes in the load of an induction motor as an illustration of induction motors in society which generally use single-phase induction motors. In this article, a 4 HP cage rotor 3-phase induction motor with a voltage of 380/220 volts is used in the electrical energy conversion laboratory of FT-UHN.

Characteristics of anthropometric and physiometric indices of volgograd schoolchildren in dynamics over 1976–2018

Introduction. The state of physical development of children and adolescents is an objective criterion of health. It is accepted to be most crucial index for predicting further child development, his readiness for sports, working life, and planning of training loads during physical education. Material and methods. The monitoring group included 7-17-year schoolchildren (820 girls, 748 boys). The body height, weight, chest circumference, the vital capacity of the lungs, the muscle strength of the hands were measured (standard techniques and instruments). A comparative assessment of the obtained indices with similar data of 1976, 2000 was performed. Results. The body height of schoolchildren decreased over the period 1976/2018, there was an increase in body of body weight. The chest circumference trend was uncertain: dropped (boys - 7,8, girls 7, 12-15 years old); increased ( boys 9-15, girls 8-11,16,17 years old). The increase in the lung vital capacity was noted mostly in boys, muscle force of the hands decreased ( boys 10, 13, 16, girls 15-16 years old ). The Stange test values have doubled in the dynamics of 7-17 years, the Genchi test increased by 73.1% for boys and by 8-10% for girls. Conclusion. The revealed features of the dynamics of anthropometrics and functional indices of schoolchildren argue the need to correct physical education programs, including the tolerance motor and power loads.

A Novel Synchronous DGs Islanding Detection Method based on Online Dynamic Features Extraction

Reliable and fast state discrimination are among the most important requirements in islanding detection methods (IDMs) to avoid islanded operation problems of distributed generation (DG) systems. This paper proposes a novel, IDM based on the dynamic response characteristics of synchronous DGs. The proposed method is based on four features of the dynamic behavior of synchronous DGs, namely, participation matrix; zero mode; oscillation frequency; and damping factor. This allows to distinguish between islanding conditions and grid-connected disturbances, even when demand and generation are closely matched. These features are extracted in practice from local measurements using Hilbert-Huang transform (HHT) technique. Moreover, a new method for online observation of the participation matrix based on online power system measurements is proposed. The impacts of synchronous DG controllers and motor loads are considered in the proposed method. Different scenarios such as load shedding, load restoration, capacitor switching, and short circuit faults have been simulated to assess the performance of the proposed method. Simulations are performed on a typical distribution system with real data for different scenarios to verify the high speed performance, reliability, robustness, and applicability of the proposed islanding detection algorithm. Comparison with alternative islanding detection methods prove the superiority of the proposed approach.

Collective Losses of Low Power Cage Induction Motors—A New Approach

Energy efficiency of systems of water pumping is a complex problem since efficiency of two distinct interacting systems needs to be combined: water and power supply. This paper introduces a non-intrusive method of calculating the so-called “collective losses” of a cage induction motor. The term “collective losses”, which the authors define, allows for accurate estimation of motor efficiency. Control system of a pump determines operating point of a pumping station, and thus its efficiency. General estimated performance characteristics of a motor, components of a control system, are assumed to serve selection of a range of pumping speed variations. Rotational speed has a direct effect on motor load torque, pump power and head, and thus on motor performance. Hellwig’s statistical method was used to specify characteristics of estimated collective losses on the basis of experimental studies of 21 motors rated at up to 2.2 kW. The results of simulations and experiments are used to verify validity and efficiency of the suggested method. The method is non-intrusive, simple to use, and requires minimum data.

DC Motor Load performance in DC system with reconfiguration of PV Array

Objectives: To examine if the changing of the series-parallel configuration of photovoltaic (PV) array can influence a simple DC drive performance. Methods: In this study, a simulated investigation is carried out for a PV system consisting of 30 panels arranged in 3*5 and 5*3, 3*6 and 6*3, 5*6, and 6*5 configuration. Two motors of rating 5 HP and 10 HP are used for the simulation. The first category includes the mentioned configuration in which the number of series PV panels (Ns) is higher than the number of the parallel panel (Np) such as 5*3, 6*3, and 6*5. The second category includes the combination in which the number of PV panels connected in parallel is higher, such as 3*5, 3*6, and 5*6. Findings: The performance of the 5HP motor gets increased by 173.36%, and the performance of the 10 HP motor gets risen by 121.26% in 18 PV panel system when Ns is higher than Np. Also, the system’s overall efficiency gets improved when Ns is higher than Np. Novelty: Usually, to vary the performance of the DC motor, power electronics circuitry is implemented. However, the performed simulated result shows that certain configurations will give better performance. Therefore, control for the DC motor’s enhanced performance can be accomplished without the power electronics control system. Keywords: PV array combination; DC motor load; Performance analysis; Simulink-Matlab

Flux-Based Detection and Classification of Induction Motor Eccentricity, Rotor Cage, and Load Defects

Motor current signature analysis (MCSA) has been accepted in the field as a reliable means of detecting faults in the rotor cage of induction motors. However, there are many limitations to MCSA-based detection for other types of faults including rotor eccentricity and load defects. Recently, there has been increasing interest in airgap or leakage flux monitoring as an alternative to replace or complement MCSA. Flux monitoring can provide a reliable means of detecting rotor faults since anomalies in the rotor magnetomotive force or airgap can be directly observed. In this article, a new method based on monitoring the attenuation of rotor rotational frequency sidebands in the flux spectra is proposed for reliable detection and classification of rotor cage and eccentricity faults. It is also shown that flux monitoring can provide detection of rotor faults that is insensitive to the load defects. An experimental study under controlled broken bar, eccentricity, misalignment, and load unbalance conditions are given to support the claims. The results show that rotor cage, eccentricity, and load defects can be detected and distinguished for cases where MCSA alone is ineffective. A comparative evaluation between the proposed flux monitoring method and existing methods (MCSA, vibration analysis) is also given.

Energy Efficiency Analysis of the Refining Unit in Thermo-Mechanical Pulp Mill

A refining model is developed to analyses the refining process’s energy efficiency based on the refining variables. A simulation model is obtained for longer-term refining energy analysis by further developing the MATLAB Thermo-Mechanical Pulping Simulink toolbox. This model is utilized to predict two essential variables for refining energy efficiency calculation: refining motor-load and generated steam. The conventional variable for presenting refining energy efficiency is refining specific energy consumption (RSEC), which is the ratio of the refining motor load to throughput and does not consider the share of recovered energy from the refining produced steam. In this study, a new variable, corrected refining specific energy consumption (CRSEC), is introduced and practiced for better representation of the refining energy efficiency. In the calculation process of the CRSEC, recovered energy from the refining generated steam is considered useful energy. The developed model results in 160% and 78.75% improvement in simulation model determination coefficient and error, respectively. Utilizing the developed model and hourly district heating demand for CRSEC calculation, results prove a 22% annual average difference between CRSEC and RSEC. Findings confirm that the wintertime refining energy efficiency is 27% higher due to higher recovered energy in the heat recovery unit compared to summertime.

Influence of Load Dynamics on Converter-Dominated Isolated Power Systems

The operation of isolated power systems with 100% converter-based generation requires the integration of battery energy storage systems (BESS) using grid-forming-type power converters. Under these operating conditions, load dynamics influences the network frequency and voltage following large voltage disturbances. In this sense, the inclusion of induction motor (IM) load models is required to be properly considered in BESS power converter sizing. Thus, this paper presents an extensive sensitivity analysis, demonstrating how load modeling affects the BESS power converter capacity when adopting conventional control strategies while aiming to assure the successful recovery of all IM loads following a network fault. Furthermore, this work highlights that generators with converter interfaces can actively contribute to mitigate the negative impacts resulting from IM loads following a network fault. Thereby, two distinct control strategies are proposed to be integrated in the power electronic interfaces of the available converter-based generators: one to be adopted in grid-following converters and another one suitable for grid-forming converters. The proposed control strategies provide an important contribution to consolidating insular grid codes, aiming to achieve operational scenarios accommodating 100% penetration of converter-based generation with a significative percentage of the IM load composition without resorting to a significative increase in BESS power converter sizing.

Zero Energy Consumption Motor Cooling Device Based on Vortex Tube Effect

In the daily operation of the industry, due to the long-term operation of machinery, the motor load is too large, resulting in motor overheating. In this paper, a kind of large-scale machine tool is designed, which uses the energy wasted in the non-working state of the large-scale machine tool to convert kinetic energy into air energy to produce compressed air with larger compressibility. Then, the compressed gas is sent to the special vortex tube. By using the structural characteristics of the vortex tube device, the cooling gas with lower temperature can be generated, which can rapidly cool the motor and improve the motor operation. The efficiency and the service life of the motor reduce the probability of motor failure in the actual production process.

Analysis of the implementation of three-phase Variable Frequency Drive on the prototype of a rice drying machine

The prototype of the rice drying machine is a device used for rice dryers that are not weather dependent. The driver of this prototype rice drying machine uses ½ HP induction motor as its main mover. To be able to adjust the rotation of the induction motor using Variable Frequency Drive (VFD) brand LS iC5 with 1 HP power. The rotation needed to rotate the load can be done by changing the frequency and voltage so that the rotation speed of the induction motor can be adjusted as needed. From the testing of a no-load induction motor with a frequency adjustment range from 5 Hz to 13 Hz, the induction motor speed is 142.8 rpm (rotation per minute) to 375.3 rpm. The measured voltage is 76.5 V to 116.7 V and the measured current is 2.5 A to 1.6 A. From the results of the test of a no-load induction motor it can be concluded that the ratio of frequency to voltage is directly proportional while the ratio of frequency to current is inversely proportional. In testing induction motors with a frequency adjustment range from 5 Hz to 9 Hz, they produce the same conclusions as to the induction motor load testing. VFD is certainly appropriate to be used as a speed regulator as needed.

Ways of constructing of measuring and starting elements of microprocessor devices of fast acting automatic transfer switch

Microprocessor devices of fast-acting automatic transfer switch (FATS) are widely spread in modern net-works to increase the reliability of power supply of industrial plants in case of short-term violations of normal power supply mode. Presence of motor load in such networks requires minimizing the power interruption time to provide more favorable conditions for self-starting of electric motors. However, currently existing operation algorithms of measuring elements of FATS devices are based on the decomposition of the measured signal by using a Fourier integral, and require observation interval equals to the period of the industrial frequency. The known directional elements that are used in microprocessor-based FATS devices do not ensure reliable operation of the device with asymmetric and nearby fault. Therefore, the purpose of the work is to increase the speed of operation of the algorithms of the measuring elements of microprocessor devices of FATS, as well as to increase the reliability of the starting directional element in case of nearby fault and deep voltage drops. To achieve this goal the author uses the method of computer simulation. The method of a full-scale experiment on a laboratory bench to verify the obtained theoretical results is used. The author improves the algorithm to determine the orthogonal components of the measured current and voltage signals by integral averaging of instantaneous discrete values of the measured signals and their derivatives over the observation interval with a duration of less than a half-period of the industrial frequency. The algorithm of the operation of the starting directional element in case of deep voltage drops caused by nearby fault in both the external and internal power supply network has been improved by using the main power supply voltage from the added memory element of the pre-fault measurement cycle as a reference voltage to determine the power direction. The obtained results show that the proposed algorithm for the operation of the measuring elements will make it possible to obtain the value of the phase and amplitude of the measured signal in a time equals to 0,005 s. and use of an improved starting directional element makes it possible to increase its reliability in case of deep voltage drops and asymmetric short circuits. The proposed algorithms of operation of the measuring elements and the starting directional element can be used in FATS devices.

An Adaptive Virtual Impedance Control for Improving Power Sharing Among Inverters in Islanded AC Microgrids

Several drawbacks of the conventional and inverse droop control based decentralized techniques for islanded microgrids are being addressed actively, over the years by various researchers. One of the prominent issues is the inaccurate power sharing (reactive power in the conventional droop and real power in the inverse droop) among the distributed generators (DGs) due to the feeder/line impedances. Virtual impedance (VI) is a popular technique to overcome impedance mismatches but the challenge is in the setting of the appropriate value. This paper presents an adaptive decentralized technique for adjusting the virtual impedance in the controller of a DG, based on its output current, without the need of communication, extra sensors or network parameter/load estimations. The methodology is tested through simulations for a wide variety of cases including unbalanced, harmonic, constant power and induction motor loads, DG plug and play functionality and performance in larger networks (modified 13 and 33 bus systems) under meshed configurations. The range for parameter stability is verified through modelling and small signal eigenvalue analyses. Further, improved power sharing performances using the proposed scheme is validated through implementation on a laboratory experimental setup.

A flexible virtual inertial control algorithm for ship with propulsion load and pulse load

The pulse load of an integrated power system (IPS) ship can produce very high power intermittently in a short period of time. Owing to the limited DC bus capacitance, the periodic pulse load charging and discharging process can make the IPS system state variables have a periodic alternating process during electromagnetic transients, especially at the bus voltage. In order to alleviate this problem, it is necessary to find a suitable control strategy. At first, this article establishes a mathematical model of DC bus voltage dynamics and propulsion motor load. Then, a flexible energy scheduling algorithm is proposed to coordinate the propulsion motor load and the pulse load based on the flexibility of IPS energy scheduling and the concept of virtual inertia. This algorithm can adaptively change the virtual inertia of the DC bus according to the pulse load power level and the propulsion motor load level to mitigate the impact of the pulse load on the IPS system. At the same time, the algorithm is also distributed and has little impact on the propulsion system. Finally, the effectiveness of the algorithm is verified through the mixed simulation of PSCAD and MATLAB and the hardware in the loop test.

Study of motor load regulation training with visual feedback in patients with diabetic polyneuropathy

BACKGRAUND: Violation of gait and body balance in patients with diabetic polyneuropathy actualizes the development of new effective measures of motor rehabilitation. In this regard, an observation was carried out in which biofeedback training was used for the reference reaction in the conditions of variable feedback parameters.AIMS: To investigate the effect of a stepwise change in the depth of feedback (sensitivity) in a motor-cognitive task with visual feedback on the reference response to the result of its execution.METHODS: Single-sample observational observation with controlled conditions. 27 patients with diabetic polyneuropathy. All patients were treated according to modern standards. The observation was performed in one series at the beginning of the course of inpatient treatment. Estimation of body balance on a power platform — stabiloplatform) — stabilometry. The procedure included 5 stages of management, in which the patient followed the instructions (training) in which there was a stepwise increase in the depth of feedback («sensitivity») at each stage from 10 to 50% of the conditional «normal», with a step of 10%. A quantitative assessment of the external result (execution of instructions) and parameters of regulation of the vertical posture was carried out.RESULTS: All patients included in the follow-up showed that the implementation of instructions with increasing depth of feedback decreased sharply when the conditionally «normal» value was exceeded by 30–35%. At the same time, the initial parameters of vertical posture control in the sample patients did not affect the dynamics of results when performing the task with visual feedback. Factor analysis indicates the presence of the only significant factor associated with the effectiveness of performing a motor-cognitive task here — changes in the depth of feedback. The accepted significance level α = 0.05.CONCLUSIONS: The depth of feedback in motor-cognitive tasks with visual feedback is a key characteristic that affects performance. The ability to increase the depth of feedback in the range of about 35; from conditionally «normal», can be useful for ensuring differentiation of loads during motor rehabilitation of patients in order to increase the effectiveness of training. In addition, in theoretical terms, the proposed model of the motor-cognitive problem can be relevant in the study of «dual» problems, where the relationship of motor and cognitive components is studied.

Вариативность координационной структуры технических действий в боксе в условиях развивающегося утомления

One of the directions of research into movement variability studies it at changing external or internal conditions during motor task performance. The results of such investigations are ambivalent even when analysing movements with similar kinematic structure. The aim of the research was to study the variability of skeletal muscle bioelectric activity and space-time characteristics of various punches in boxing at fatigue. Six highly skilled boxers of different weight classes were involved. We analysed parameters of variation of muscle electromyographic activity, distance and speed of the anthropometric points of body segments, as well as joint movement amplitude under regular conditions and after an aerobic motor load. We found low amplitude variability in most of the skeletal muscles under study, both in regular conditions and after a motor load. At fatigue, amplitude variability of almost all muscles decreased. Under regular conditions, the movement amplitude of the shoulder, elbow and hip joints on the bodyʼs right side was more varied than that in the joints on the left. After a motor load, changes in the variability of joint movement amplitude during the performance of different punches were dissimilar. The most variable were changes in the angles of the right side of the body, especially the elbow and hip joints, when performing a direct punch. The least changes under the load were observed in the movement amplitude of the elbow and hip joints on the left side. Thus, variability changes in kinematic parameters caused by skeletal muscle activity are a mechanism for maintaining stability of motor task performance. Presumably, the central neural control of complex coordination movements in boxers when performing punches is carried out through the formation of kinematic and muscle synergies. More research is needed to clarify the mechanism of formation and functioning of kinematic synergies and their variability.

Calculation of the Capacity for the Operation of a Mini-Energy Complex Based on an Inde-pendently Operating Asynchronous Generator

The article present the analysis of the operation of the mini-energy complex (MEC) based on alternative energy sources. An asynchronous generator (AG) was taken as energy source. The IEC operates independently with standard power parameters without the use of a frequency converter. To operate independently, AG needs a source of reactive excitation current. Based on the calculations carried out and the results obtained with the use of the experimental facility,the operating conditions of the MEC with standard parameters of electricity under varying load have been analyzed. A characteristic feature of the autonomous MEC is the commensurate capacity of the generating device and consumers. Therefore, any power consumer on/off leads both to significant changes of local electric system parameters and affects the operation of the generator itself. In this article, the main attention is paid to the influence of three-phase motor load on stable AG operation. When the MEC operates independently, reliable self-excitation of the asynchronous generator and the start-up of consumers whose power is commensurate with the generating unit must be ensured. It is also necessary to ensure the maintenance of voltage stability, the possibility of automatic operation of the generating unit, and the preservation of its integrity in emergency modes. Thus, for stable MEC-based AG operation the nature of the load should be taken take into account, the parameters of the of the local grid should be known as well as the exact availability of consumers and their characteristics, and also equivalent circuit parameters of asynchronous motors. In addition, it is necessary to accurately calculate the capacity when changing the parameters of the electrical system, so as not to lose the self-excitation of the asynchronous generator, which is equivalent to disconnecting the entire load of the generator and causes a sharp increase in speed. To solve these problems, it is necessary to create a high-speed MEC control system.

Specifics of Emergency Operation in Distribution Grid and their Effect on Integration and Functioning of Distributed Generation Facilities

This paper focuses on the characteristic features of distribution grids, which have the greatest impact on the stability of generators and motor loads. It shows that severe accidents in distribution and transmission grids differ in nature, starting with an overload leading to line disconnections and further evolving into a voltage collapse. It appears that where generator capacity is commensurate with the total power of motors in a grid, the motor load has a significant impact on transients. The paper discusses how asynchronous operation is triggered, progresses, and can be addressed in a grid with distributed generation (DG) facilities. It further analyzes the consequences of deep grid sectionalization and proves why grid structure needs to be optimized for further development. The paper also shows how to take into account the specifics of emergency processes (i.e., accident-associated processes) in distribution grids when integrating and operating DG facilities.

Mechanobiology of Stator Remodeling in the Bacterial Flagellar Motor

Motility is critical for the survival and dispersal of bacteria, and it plays an important role during infection. How bacteria regulate motility is thus of great interest to microbiologists, ecologists, and infectious disease researchers alike. Regulation of motility via chemotaxis and gene regulation is well studied. However, recent work has added a new dimension to this problem. The flagellar motor of bacteria autonomously assembles and disassembles torque-generating stator complexes in response to changes in the external viscous load. in the bacterium Escherichia coli, up to 11 stator complexes drive the motor at high load while all the stator complexes are released at low load. We study this process by artificially manipulating the motor load using electrorotation, where a high frequency rotating electric field applies an external torque on the flagellar motor. Using this technique, we can increase or decrease the motor load at will and measure the resulting stator assembly dynamics. From detailed measurements of stator remodeling in both clockwise and counterclockwise rotating motors, we have found that the motor's response has a conserved torque dependence. increased torque decreases the dissociation rate of stator complexes from the motor, thereby increasing the steady state stoichiometry. We built an equilibrium model that captures the observed dynamics and provides insight into the underlying molecular interactions. Torque-dependent stator remodeling takes place within tens of seconds, making it a highly responsive autonomous control mechanism.

Research on Model Predictive Control Based on Sensorless Permanent Magnet Synchronous Motor

For permanent magnet synchronous motor (PMSM) speed control system, aiming at the problems of slow dynamic response and large dependence on system model parameters of traditional PI control of PMSM, the model predictive current control strategy is adopted to design the predictive model. Aiming at the problems of poor reliability and high cost of traditional permanent magnet synchronous motor with mechanical sensor, the speed sensorless control technology is introduced to design the control structure, and the rotor position and speed are estimated by sliding mode observer method. Through simulation verification, the results show that the combination of the above two control methods can obviously improve the performance of the traditional permanent magnet synchronous motor control system, and has strong robustness under the conditions of motor parameters and load changes.

Improving the torque direct control method of the asynchronous motor in the converter using the active rectifier

The frequency converter study has shown that controlled rectifiers, also known as active rectifiers, have many advantages over uncontrolled rectifiers (diode bridges). The frequency converter with an active rectifier ensures that the input current is sinusoidal, the power factor is 1, the DC voltage constant at the output, the energy exchange according to bidirectional is between the load and grid. The voltage oriented control for the active rectifier will measure the grid voltage and use current control circuits or instantaneous power control circuits. The paper analyses the advantages of using the method of controlling the current in the rectifier circuit when working with the three-phase motor load. The torque direct control method of the motor is enhanced by selecting a new switch table of the voltage vector. The combining power, an active rectifier circuit, inverter, motor, and load create a complete electric drive system with improved working efficiency. The research results were verified by Matlab&Simulink software.