Application Of Induction Motors Research Articles

Finite-Element Transient Analysis of Induction Motors Under Mixed Eccentricity Fault

In a three-phase squirrel-cage induction motor, eccentricity is a common fault that can make it necessary to remove the motor from the production line. However, because the motor may be inaccessible, diagnosing the fault is not easy. We have developed a time-stepping finite-element method (FEM) that identifies mixed eccentricity (a combination of static and dynamic) by analysis, without direct access to the motor. The method overcomes the difficulty of applying FEMs to transient behavior. It simulates the spectrum of the line current of a production-line motor and compares it to the spectrum of a known healthy motor to detect eccentricity. Agreement between the simulation and actual measurements of eccentricity is good.Protection and fault diagnosis are integral to sound application of three-phase squirrel-cage induction motors in industry. Eccentricity is a common fault in induction motors that might force the motor to be removed from the production line. However, diagnosis of this fault due to inaccessibility to the rotor is not easy. Performance analysis, investigation and diagnosis of static, dynamic and mixed eccentricities at steady-state and during transient modes have already been published using analytical methods. However, study of static and dynamic eccentricities only at steady-state using finite element method (FEM) has been previously reported. This paper uses time stepping FE (TSFE) method with voltage-fed source for performance analysis and diagnosis of mixed eccentricity in induction motor at start up. The method used here overcomes the difficulty of FE application which makes it possible to analyze the transient behavior of a faulty induction motor. Spectra of line current of healthy motor and motor under mixed eccentricity conditions are predicted by simulation and then compared with the experimental results. This comparison shows a very good agreement between the simulation and test results.

Application of Linear Induction Motor for Tension Supply and Heating to Thin Steel Sheet

Application of Linear Induction Motor for Tension Supply and Heating to Thin Steel Sheet

Dynamical models for fault detection in squirrel cage induction motors

Induction motors are the dominant components in industrial processes involving electromechanical energy conversion. Safety, reliability and efficiency are major concerns in modern induction motor applications. Since detecting faults on time could avoid costly unscheduled shutdowns, in recent years there has been an increased interest in induction motor fault detection and diagnosis. In this paper, we propose monitoring schemes to solve fault detection problems of induction motors. We begin with a monitoring scheme to detect detuning operation in Indirect Field Oriented Control (IFOC) driven induction motors. Secondly, we present a monitoring scheme to detect broken rotor bars on IFOC-driven induction motors. The proposed monitoring scheme does not rely on spectral methods; instead, it monitors a carefully selected induction motor state, using an online observer. The key to fault detection is the development of a simplified dynamic model of a squirrel cage induction motor with broken rotor bars. Numerical simulations validate both monitoring schemes.

The Analysis of Motivation Factors in Application on Linear Induction Electric Drives

The article deals with the factors of application of linear induction motors from the point of view of system engineering: the factor of equipment construction simplification, factor of application of LIM features in elaborated flexible production systems, the factor of possibility to apply of non-traditional control and regulation methods, the factor of LIM secondary element catapulting and levitation, factor of modular system designing, factor of control system simplification considering the LIM specific features, fast-operation factor, factor of multifunctionality, factor of movement transfer to closed space determined the successful development of real and exploited systems with LIM. The examples of developed automatic systems are presented; the principles of their performance are analyzed. Ill. 3, bibl. 8 (in English; summaries in, English, Russian and Lithuanian).

Induction motors with YY/D connection change for efficiency and power factor increasing at partial loads

It is established that there exists a significant possibility for energy savings, on the basis of application of induction motors with YY/D connection change proposed in this paper, especially for power to 30 kW. In connection D (0.866Un), total losses and reactive loads are reduced to loads up to 75-85%. Benefits of such motors would be significant because more than 80% induction motors are light loaded (mean value ? 70%). In such manner one motor with two characteristics is attained, but that is better than to offer to the market two different motors, because only in exploitation it is possible to accurately select the one which is working with greater efficiency values in given conditions. However, at the motor with YY/D winding it is always possible, by selection of corresponding connection for (mean value) load measured in operation. Even, with connection change it is possible to adjust to load changes in future. Moreover, at loads ? 30%, energy saving by induction motors with YY/D connection is greater than the one using induction motors with thyristor controllers. Induction motors YY/D connection application may be economical in cases where it is not recommended to use higher costs of energy efficiency of motors.

New concept of electrical drives for paper and board machines based on energy efficiency principles

In this paper, it is described how the reconstruction of the facility of paper machine has been conducted, at the press and drying part of the machine in June 2001, as well as the expansion of the Paper Machine with the "third coating" introducing, that has been done in July 2002, in the board factory "Umka". The existing old drive of the press and the drive of drying groups were established as a Line Shaft Drive, 76 m long. The novel drive is developed on the basis of conventional squirrel cage induction motor application, with frequency converter. The system control is carried out with the programmable controller, and the communication between controllers, converters, and control boards is accomplished trough profibus. Reconstruction of the coating part of the machine, during technological reconstruction of this part of the machine, was being conducted with a purpose to improve performance of the machine by adding device for spreading "third coating". The demands for the power facility were to replace existing facility with the new one, based on energy efficiency principles and to provide adequate facility for new technological sections. Also, new part of the facility had to be connected with the remaining part of the machine, i.e. with the press and drying part, which have been reconstructed in 2001. It has to be stressed that energy efficiency principles means to realize new, modernized drive with better performances and greater capacity for the as small as possible amount of increased installed power of separate drives. In the paper are also, graphically presented achieved energy savings results, based on measurements performed on separate parts of paper machine, before and after reconstruction. .

IRFOC induction motor with rotor time constant estimation modelling and simulation

PurposeTo provide a new and simple inverse rotor time constant identification method which can be used to update an indirect rotor field oriented controlled (IRFOC) induction motor algorithm.Design/methodology/approachTwo different equations are used to estimate the rotor flux in the stator reference frame. One of the equations is a function of the rotor time constant, rotor angular velocity and the stator currents. The other equation is a function of measured stator currents and voltages. The equation that uses the voltage and the current signals of the stator serves as reference model, however, the other equation works as an adjustable model with respect to the variation of the rotor time constant. Voltage signals used in the reference model equation are obtained from the measured DC bus voltage and the inverter gating signals. The proposed scheme is verified using a MATLAB/SIMULINK model for two different motors and experimentally using a DSP development tool (MCK 243) supplied by Technosoft S.A.FindingsThe proposed estimator was able to successfully track the actual value of the inverse rotor time constant for different load torque and speed operating conditions. Increased oscillations in the estimated inverse rotor time constant appeared at lower speeds (below 10 per cent of rated speed) due to drift in a PI regulator (used at the estimator side), which was tuned under rated operating conditions and using parameters nominal values.Research limitations/implicationsThis estimation scheme is limited when near zero speed operation is demanded; otherwise it gives a simple and practical solution. A suggested way out of this, is to provide a self‐tuning controller that can automatically adjust even for zero speed operation, or to automatically disconnect the estimator and take the most updated value as long as the operating speed is below a predetermined value.Originality/valueThis paper presented a new inverse rotor time constant estimator for an IRFOC induction motor application and in conjunction rotor flux was estimated without voltage phase sensors.

DSP 마이크로컨트롤러를 사용한 CAN 네트워크 기반 유도전동기고장진단 시스템 설계

Induction motors are a critical component of many industrial processes and are frequently integrated in commercially available equipment. Safety, reliability, efficiency, and performance are some of the major concerns of induction motor applications. Fault tolerant control (FTC) strives to make the system stable and retain acceptable performance under the system faults. All present FTC method can be classified into two groups. The first group is based on fault detection and diagnostics (FDD). The second group is includes of FDD and includes methods such as integrity control, reliable stabilization and simultaneous stabilization. This paper presents the fundamental FDD-based FTC methods, which are capable of on-line detection and diagnose of the induction motors. Therefore, our group has developed the embedded distributed fault tolerant and fault diagnosis system for industrial motor. This paper presents its architecture. These mechanisms are based on two 32-bit DSPs and each TMS320F2407 DSP module processes the stator current, voltage, temperatures, vibration signal of the motor.

Determining torque–speed curve of two-speed deep cage lift asynchronous machines

Typical rated slip for most induction motor applications lies below 15%, and the concern about their torque–speed curve, when existing, refers to slips of only up to 100%, and then usually with somewhat loose requirements (like minimum or average starting torques). However, for two-speed lift motors, a very reliable determination of the T–n curve is necessary, especially at the extremely high slips of up to 300% appearing in their working cycle. Therefore a precise determination of leakage reactance together with an accurate analysis of bar current displacement and end-ring current distribution become unavoidable. A systematic investigation is made on four gradually more sophisticated steady-state models (the first three of them rather well known to specialists) used to predict the T–n curve from machine design data. The comparison of all model results with the T–n curve measured in more than 30 industrial lift motors makes evident, and allows a clear appreciation of, the limitations and range of validity of each model when faced with such a demanding application and, at the same time, confirms the suitability of the proposed fourth model.

Optimized thrust control of linear induction motors by a compensation approach

This paper describes a solution to the control problems that can be associated with the application of the linear induction motor (LIM) in urban transportation. In order to meet the principle objective of LIM control - the peak thrust tracking - a new compensation technique is presented. The control system has additionally been verified by use of the appropriate finite element field calculations of the LIM and measurements done on the test machine.

Influence of Unbalanced and Waveform Voltage on the Perfomance Characteristics of Three-phase Industion Motors

This paper examines the proper application of three-phase induction motors when supplied by unbalanced and harmonics voltage. The proposed is show that a poor power quality voltage have bad effects over the motor performance: loss, temperature rise, rated horsepower, efficiency , magnetic noise and reliability. Finally this paper present recommendations in order to increase the reliability of inductions motors operations.

Circuit model for shaft voltage prediction in induction motors fed by PWM-based AC drives

The development of high-frequency pulsewidth-modulation-based adjustable-speed drives (ASDs) has increased the efficiency, performance, and controllability in induction motor applications. However, the high switching frequencies and the faster switching times of insulated gate bipolar transistors (the device of choice in these ASDs) introduce disadvantages like overvoltages at the motor terminals when long cables are used between the drive and the motor. Another industry-wide concern is the generation of rotor shaft voltage and the resulting bearing current. The grease film in a bearing acts as a capacitor that charges due to the transitions in the common-mode voltage imposed at the motor terminals by the drive. The breakdown of the film causes a spike of current to flow that can damage the bearing and reduce life. A significant amount of effort has been directed at understanding the shaft voltage phenomenon and the associated bearing current. This paper attempts to develop circuit models to predict the level of the shaft voltage. The circuit models can then be used to predict the shaft voltage levels at different installations, using simulation software like PSpice. Circuit models for two specific motors are developed. The predicted shaft voltage is very close to the actual voltage levels seen on the shaft when the motors are operated by ASDs.

Thermal evaluation for applying TEFC induction motors on short-time and intermittent duty cycles

There are many applications of induction motors to cyclic loading. Most motor manufacturers will perform calculations to obtain motor stator temperature rise for variable-load and cyclic loadings based on data provided. This paper is a report of a testing program on totally enclosed fan-cooled induction motors where temperatures for loadings are measured.

Comparison testing of IEEE standard 841 motors

The IEEE Standard 841 was developed to identify additional specific features deemed necessary for application of induction motors in the petroleum and chemical industry. The Pulp and Paper Industry Committee (PPIC) of the IEEE Industry Applications Society has also been studying the IEEE Standard 841 for possible adoption by the pulp and paper industry. Members of the PPIC Ad Hoc Committee on IEEE 841 have suggested additional requirements to those in the existing standard. This paper discusses a comparison testing program conducted by the Motor Systems Resource Facility, an EPRI/BPA center at Oregon State University, Corvallis, in support of an industrial investigation of the available motors manufactured to the IEEE Standard 841. Seven major motor manufacturers participated in this study. Each manufacturer provided a 50-hp, a 100-hp, and a 200-hp "Standard" IEEE 841 motor for examination on delivery and IEEE 112 Method A efficiency testing. All of the motors were horizontal, three phase, 60 Hz, four pole, and 460 V (except one that was 575 V).

Analysis of Supply Voltage Distortion Effects on Induction Motor Operation

Many modem induction motor applications involve nonsinusoidal voltage supply. Under such operating conditions the motor performance can be seriously affected while the standard equivalent circuit is no more adequate for the motor analysis. In this paper, a modified equivalent circuit topology is introduced in order to account for the increased iron losses associated with the leakage flux and saturation in the motor, in presence of low-order harmonics in the supply waveform. This equivalent circuit allows the prediction of the motor performance under nonsinusoidal operation. The proposed results have been checked by means of an experimental setup comprising an inverter-fed 1.5 kW induction motor.

Direct torque control of induction motors: stability analysis and performance improvement

Practitioners in the electric drives community have recently introduced a novel torque control strategy for high power induction motor applications, called direct torque control (DTC), which has three distinctive features: 1) it focuses on stator flux regulation; 2) it does not aim at an asymptotic system inversion; and 3) it explicitly takes into account the discrete nature of the control actions. Besides its simplicity, it is claimed that the achieved performance is superior to field oriented strategies because of the digital form of the control structure and the reduced dependence on parameter variations of the stator flux calculations. Our objective in this paper is twofold: 1) to carry out a mathematical analysis of the stabilization mechanism of DTC, which helps us assess the achievable performance of the current scheme and provide guidelines for its tuning; and 2) to propose a modified DTC to improve its dynamical behavior. Experimental results are presented to illustrate the main points of our paper.

Torque characteristics and application of two-phase induction motor driven by two power supplies with nearby frequencies

Torque characteristics and application of two-phase induction motor driven by two power supplies with nearby frequencies

Torque characteristics and application of two-phase induction motor driven by two power supplies with nearby frequencies

When two power supplies with nearby frequencies are connected to a two-phase induction motor, the motor generates two kinds of oscillatory torque components, which have frequency components of the sum and the difference between the frequencies of the power supplies. These oscillatory torque components are sinusoidal, and the torque with the frequency component of the difference is considerably larger than the torque with the frequency component of the summation. Consequently, the motor behaves as a swing motor, which alternately changes the direction of rotation. Because of the regularity of the period of the human heartbeat, this swing motor is suitable for use as the driver of an artificial heart. We propose here to use this swing motor as the pump for artificial hearts. In this paper, we present the fundamental theory and the characteristics of the swing motor, and an outline of the motor action for artificial hearts. © 2000 Scripta Technica, Electr Eng Jpn, 132(1): 73–80, 2000

Selection and application of a 16000-hp induction motor

In December 1996, Messer-AGS began engineering and procurement of equipment for a 900 metric-ton-day air separation unit (ASU) to be located near Kuala Lumpur, Malaysia. Principle products of this facility are industrial gases via pipeline to the customer, liquid products for the area merchant market, and a cylinder filing operation for these products for local use. The primary user of these products is a large steel manufacturing facility adjacent to the ASU. The design requirements for the plant are outlined with emphasis on the motor. The selection and design of the 16000 hp induction motor are discussed.

A motor primer. I

Much has been written about applying motors on variable-speed drives, high-speed rigid shaft motors, impact on API Standard 541, motor diagnostics, etc. Most of these papers and articles assume that the reader has significant knowledge of motor theory and operation. However, this assumption is overly optimistic, considering that few if any, colleges teach motor theory today and that application experience at motor user locations has been reduced. This paper is the first of a series of papers. The authors present induction motor theory and application information with an extensive reference list that will help engineers understand such questions as: what causes a motor to make noise? Why is a medium-voltage motor different than a low-voltage motor? How should a motor be grounded? etc. This paper serves as a valuable reference for those who apply and specify motors.