Efficiency Of Induction Motor Research Articles

Enhancement of Energy Efficiency in Squirrel Cage Induction Motors Using DCR Technology

Enhancement of Energy Efficiency in Squirrel Cage Induction Motors Using DCR Technology

Analysis of Induction Motor Efficiency Enhancement

Analysis of Induction Motor Efficiency Enhancement

An Evaluation of Induction Machine Stray Load Loss From Collated Test Results

The international standards for determining induction motor efficiency are not in agreement with each other. At the heart of the differences is the stray load loss (SLL). The way this loss is quantified is continuously debated. For many years, the IEC standard for motor efficiency measurement has assigned a fixed percentage to stray load loss. This fixed percentage value has been criticized throughout the history of the standard. A new version of the standard published in September 2007 replaced the fixed percentage with one that is dependent on motor kW rating through a specific relationship. One of the goals of this paper is to determine whether the new formula for assigning the SLL can be confirmed with actual test data. This paper presents a collection of test data on about 1000 motors to show the distribution of stray load losses in induction motors. The analysis clearly demonstrates the need for determining stray loss from test measurements rather than assigning an arbitrary value.

Improvement of capacitor induction motor efficiency by using 3-Dimensional finite element method

In this paper, we analyze the steady state characteristics o f an experimental capacitor motor by 3-D non-linear FEM coupled with the voltage equation. Next, we propose several methods to improve the motor efficiency by considering the flu x density distribution. The motor model where the rotor bars are spread inside can improve the motor efficiency by 4.7%.

Designing More Efficient Large Industrial Induction Motors by Utilizing the Advantages of Adjustable-Speed Drives

The rotor of an induction motor is designed to provide adequate starting torque and limit starting current when the load is being accelerated by the motor. These starting requirements on the rotor force design engineers to employ special shape rotor bars or high-resistance bars and thereby reduce motor efficiency and increase motor temperature rise. In addition to the benefits provided by an adjustable-speed drive (ASD) in controlling operating speed, this paper evaluates the benefits of ASD in allowing engineers to design higher efficiency motors and, in turn, smaller size motors.

Non Invasive Sensors for Monitoring the Efficiency of AC Electrical Rotating Machines

This paper presents a non invasive method for estimating the energy efficiency of induction motors used in industrial applications. This method is innovative because it is only based on the measurement of the external field emitted by the motor. The paper describes the sensors used, how they should be placed around the machine in order to decouple the external field components generated by both the air gap flux and the winding end-windings. The study emphasizes the influence of the eddy currents flowing in the yoke frame on the sensor position. A method to estimate the torque from the external field use is proposed. The measurements are transmitted by a wireless module (Zig-Bee) and they are centralized and stored on a PC computer.

Efficiency Optimization of Induction Motor Drive Using Soft Computing Techniques

This paper presents a new approach that minimizes copper & iron losses and optimizes the efficiency of a variable speed Induction motor drive. This method is based on a simple induction motor field oriented control model includes iron losses uses only conventional IM parameters. In literature, Fuzzy logic and Genetic Algorithms have been used for efficiency optimization of induction motor drives. This paper proposes integration of Fuzzy model identification and PSO algorithm for loss minimization. An improvement of efficiency is obtained by adjusting the magnetizing current component with respect to the torque current component to give the minimum total copper and iron losses. The whole circuit is simulated using MATLAB 7.6. The proposed method is compared with other soft computing techniques. The results obtained by Fuzzy PSO shows better results compared with other approaches. General Terms Algorithms, Performance, Verification

The Influence of Supply Voltage Amplitude Variation Law on AC Induction Motor Efficiency in Variable-Speed Drive

This paper presents investigation results of the influence of the supply voltage amplitude variation law on the efficiency of AC induction motor in variable-speed drive based on the frequency converter. It is demonstrated that the commonly employed linear and square voltage amplitude variation laws do not provide the highest efficiency of the AC induction motor. The corrected AC voltage amplitude variation dependences for different motor load torque, at which high efficiency of the motor supplied by the frequency converter is maintained, are proposed and discussed. Reported experimental study was performed on a special test bench.

Study of a Novel Energy Efficient Single-Phase Induction Motor With Three Series-Connected Windings and Two Capacitors

This paper presents a novel energy efficient single-phase induction motor with three series-connected windings and two capacitors. By suitable selection of capacitors, the currents in three windings are approximately symmetrical, and thus, the motor can operate approximately symmetrically from single-phase supply. Based on the symmetrical components method, the condition for balanced operation is studied, and the method for determining capacitances is proposed. The performance analysis method is put forward to calculate the steady performances. Performance tests are performed on the proposed motor and three-phase induction motor. It is proved that their rated efficiency is approximately the same, while the power factor of the former is higher than that of the latter. In comparison with the ordinary single-phase induction motor, it has the advantages of higher efficiency and smaller volume, thus can take the place of the latter in some applications.

Design optimization of three‐phase energy efficient induction motor using adaptive bacterial foraging algorithm

PurposeThe purpose of this paper is to present the application of an adaptive bacterial foraging (BF) algorithm for the design optimization of an energy efficient induction motor.Design/methodology/approachThe induction motor design problem is formulated as a mixed integer nonlinear optimization problem. A set of nine independent variables is selected, and to make the machine feasible and practically acceptable, six constraints are imposed on the design. Two different objective functions are considered, namely, the annual active material cost, and the sum of the annual active material cost, annual cost of the active power loss of the motor and annual energy cost required to supply such power loss. A new adaptive BF algorithm is used for solving the optimization problem. A generic penalty function method, which does not require any penalty coefficient, is employed for constraint handling.FindingsThe adaptive BF algorithm is validated for two sample motors and benchmarked with the genetic algorithm, particle swarm optimization, simple BF algorithm, and conventional design methods. The results show that the proposed algorithm outperforms the other methods in both the solution quality and convergence rate. The annual cost of the induction motor is remarkably reduced when designed on the basis of minimizing its annual total cost, instead of minimizing its material cost only.Originality/valueTo the best of the knowledge, none of the existing work has applied the BF algorithms for electrical machine design problems. Therefore, the solution to this problem constitutes the main contribution of the paper. According to the huge number of induction motors operating all over the world, the BF techniques used in their design, on minimum annual cost basis, will lead to a tremendous saving in global energy consumption.

Application Of Artificial Neural Network In The Efficient Control Of Three-phase Induction Motor

This work presents a method for increasing the efficiency of three-phase induction motor drives over the entire operation range. The direct field oriented control of induction motors, including the effects of magnetic saturation is used. The magnetic saturation effect in the machine is modeled by the non-linear magnetization curve of the iron core. Artificial neural networks are used to predict the optimum reference rotor flux to be used in the vector control. Details about the chosen neural networks are given. Simulation and experimental results are presented and the motor losses reduction during different load conditions is evaluated.

Stator Current and Motor Efficiency as Indicators for Different Types of Bearing Faults in Induction Motors

This paper proposes a new approach to use stator current and efficiency of induction motors as indicators of rolling-bearing faults. After a presentation of the state of the art about condition monitoring of vibration and motor current for the diagnostics of bearings, this paper illustrates the experimental results on four different types of bearing defects: crack in the outer race, hole in the outer race, deformation of the seal, and corrosion. The first and third faults have not been previously considered in the literature, with the latter being analyzed in other research works, even if obtained in a different way. Another novelty introduced by this paper is the analysis of the decrease in efficiency of the motor with a double purpose: as alarm of incipient faults and as evaluation of the extent of energy waste resulting from the lasting of the fault condition before the breakdown of the machine.

Optimized Design of High-Speed Induction Motors in Respect of the Electrical Steel Grade

This paper presents the design of highly efficient high-speed induction motors with optimally exploited magnetic materials. First, new combined numerical-analytical design methods are presented and validated, which closely relate to the classical way of machine design but allow the designer to precisely account for material properties. Second, it is shown how two optimized 20-kW 30 000-r/min induction machines have been realized, i.e., one incorporating cobalt-iron alloy, and the other one using siliconized steel. Finally, the influence of the electrical steel grade on their performance is evaluated on the basis of electrical, thermal, vibrational, and noise measurements.

Analysis of induction motor efficiency class change at partial load

Motors with efficiency high values can became inefficient then standard motors when they are lightly loaded. The calculation procedure for the estimation of any part load efficiency when two load points are given is presented in paper. Efficiency dependence is expressed in the form of ? =?N ?k(1-?N), where is magnitude kP = f1(P0,P?N,P/PN), so that changes-deviations of efficiency values compared to rated value (?N) would be explicitly expressed. Based on those deviations, energy efficiency class changes of observed motors are directly identified with load change. Efficiency curve for several motors, with typical shapes, are considered, especially for loads P/PN = 0.50-1.00. These results are shown justification claim that efficiency values at 50% and 75% load shall be stated in the documentation. The users can then select the motor best suited for their application.

Efficiency determination of induction motors using multi-objective evolutionary algorithms

This paper introduces a method based on multi-objective evolutionary algorithms for the determination of in-service induction motor efficiency. In general, the efficiency is determined by accumulating multiple objectives into one objective by a linear combination and optimizing the resulting single-objective problem. The approach has some drawbacks such that exact information about solution alternatives will not be readily visible. In this paper the multi-objective evolutionary optimization algorithms, the Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Strength Pareto Evolutionary Algorithm-2 (SPEA2), are successfully applied to the efficiency determination problem in induction motor. The performances of algorithms are compared on the basis of the obtained results.

Fault induction dynamic model, suitable for computer simulation: Simulation results and experimental validation

The study of induction motor behavior under not normal conditions and the ability to detect and predict these conditions has been an area of increasing interest. Early detection and diagnosis of incipient faults are desirable for interactive evaluation over the running condition, product quality guarantee, and improved operational efficiency of induction motors. The main difficulty in this task is the lack of accurate analytical models to describe a faulty motor. This paper proposes a dynamic model to analyze electrical and mechanical faults in induction machines and includes net asymmetries and load conditions. The model permits to analyze the interactions between different faults in order to detect possible false alarms. Simulations and experimental results were performed to confirm the validity of the model.

Influence of Bus Voltage on Motor Torque and Efficiency in Fuel Cell Hybrid Powertrain

AbstractIn order to evaluate the influence of bus voltage on motor torque and efficiency, bench experiments were designed on a dynamic dynamometer. The torque and efficiency of three-phase asynchronous induction motor were measured with the bus voltage changing between 400 V and 455 V. The result shows that (1) the motor efficiency is mainly affected by the bus voltage in low-efficiency area, actual motor torque has an average delay time of 0.5 sec compared to the target torque command; (2) actual torque is lower than target torque in high-bus voltage and high-motor speed range because of self-protection of the motor controller. Results in “Chinese typical city bus cycle” testing shows that the working points are mainly distributed in the high efficiency area which is affected by bus voltage slightly. As a result, the influence of bus voltage on motor efficiency could be ignored in city bus cycle analysis.

The Partial-Load Efficiency of Induction Motors

This paper presents result of a project that enabled older operating motors to be removed from service and tested for efficiency under laboratory conditions, with the displaced motors being replaced by new National Electrical Manufacturers Association premium motors. The objective of the project is to determine the efficiency of a population of motors in operation before the Energy Policy Act of 1992 and to investigate if there was economic justification in replacing such motors with new ones. The economic benefit of repair/replace is computed at the tested partial-load efficiency of the motors. In addition, results are presented that show the load point at which maximum efficiency occurs for each motor. The differences in the partial-load characteristics of the old and new motors are also discussed.

Noninvasive Procedure for Improving Efficiency of Three-Phase Induction Motors

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In developing countries, three-phase squirrel cage induction motors, even though with load equal to their name plate rating, may operate at low efficiencies. This may be because their winding parameters are not optimized for lower running cost. To ascertain the cause, it is necessary to know the stator winding data and compare it with the results of the design. If a deviation exists, the winding is improper. However, it may be possible to improve efficiency by rewinding the motor. We propose a noninvasive procedure to determine the following winding data: number of parallel circuits in a phase, number of turns per coil, and conductor area. The procedure includes a new iterative algorithm for determining these winding data. We discuss experimental investigations to validate the proposed procedure and to test its effectiveness in energy conservation. We outline the usefulness of the procedure for designers and the advantages it offers to service providers and educational institutions. </para>

How the efficiency of induction motor is measured?

The efficiency is of paramount importance nowadays due to increasing electrical energy demand, increasing awareness of environmental problems as greenhouse effects and increasing fossil fuel prices. This paper tries to show the different results between the standards for efficiency evaluation and the necessity of harmonization worldwide. Then, it is going to be explained the different standards for measurement of efficiency, and the main differences between the standards (IEEE 112, IEC 60034-2 and JEC-37). To complete this study, it is going to be described the steps in order to estimate efficiency on the jobsite and expressed the different efficiency labels motors.