Efficiency Of Three-phase Induction Motors Research Articles

Assessment of the Energy Efficiency of Three-Phase Induction Motors Powered by A Photovoltaic System

This study aims to determine the energy efficiency of three-phase induction motors (TIM) powered when operated with photovoltaic systems (PVS). The environmental advantages of photovoltaic systems (PVS) are very well known. However, there are still challenges related to energy quality, electricity generation instability, failure in frequency regulation, instability in reactive power, and harmonics generation. However, the impact of PVS on TIM efficiency has not been thoroughly explored. This research compares a TIM's electromechanical characteristics and efficiency when powered by a conventional electrical grid versus a PVS. Experimental studies revealed that when powered by the PVS, the TIM experienced increased voltage and higher voltage and current harmonics compared to grid power. These electrical difficulties, attributed to the PVS inverter, resulted in a 2.7% decrease in TIM efficiency compared to grid power. Modeling conducted under actual load variation conditions demonstrated a 2.6% increase in energy consumption when powered by the PVS compared to grid power. Based on these findings, PVS installers are advised to consider the energy quality provided by these systems, as it may affect the efficient operation of TIM, leading to increased energy consumption.

An Alternative Methodology for Quantifying Voltage Unbalance Based on the Effects of the Temperatures and Efficiency of Induction Motors

Many unbalanced voltage conditions, which produce different effects on electric equipment, are associated with the same voltage unbalance factor. This fact hinders the precise association between the values of this index and the effects of voltage unbalance. In the present study, an alternative methodology for quantifying voltage unbalance based on the effects of this phenomenon on the temperature and efficiency of three-phase induction motors is proposed. The application of the suggested methodology results in an index that contemplates the combined effects of the modules and angles of the positive and negative sequence voltages. Aiming to apply this methodology and evaluate its performance, we selected a comprehensive set of balanced and unbalanced voltage conditions and used it on a three-phase induction motor. The results show that the index obtained, when compared to the traditional voltage unbalance factors, reduces the uncertainties inherent to the quantification process of this phenomenon. In other words, it allows a better association between the values and effects of the voltage unbalance. For these reasons, this index is considered as a potential alternative that can be employed in industrial utilities and standards that deal with voltage unbalance.

Neutral Current Reduction in Three-Phase Four-Wire Distribution Feeders by Optimal Phase Arrangement Based on a Full-Scale Net Load Model Derived from the FTU Data

An increase in the neutral current results in a malfunction of the low energy over current (LCO) protective relay and raises the neutral-to-ground voltage in three-phase, four-wire radial distribution feeders. Thus, the key point for mitigating its effect is to keep the current under a specific level. The most common approach for reducing the neutral current caused by the inherent imbalance of distribution feeders is to rearrange the phase connection between the distribution transformers and the load tapped-off points by using the metaheuristics algorithms. However, the primary task is to obtain the effective load data for phase rearrangement; otherwise, the outcomes would not be worthy of practical application. In this paper, the effective load data can be received from the feeder terminal unit (FTU) installed along the feeder of Taipower. The net load data consisting of customers’ power consumption and the power generation of distributed energy resources (DERs) were measured and transmitted to the feeder dispatch control center (FDCC). This paper proposes a method of establishing the equivalent full-scale net load model based on FTU data format, and the long short-term memory (LSTM) was adopted for monthly load forecasting. Furthermore, the full-scale net load model was built by the monthly per hour load data. Next, the particle swarm optimization (PSO) algorithm was applied to rearrange the phase connection of the distribution transformers with the aim of minimizing the neutral current. The outcomes of this paper are helpful for the optimal setting of the limit current of the LCO relay and to avoid its malfunction. Furthermore, the proposed method can also improve the three-phase imbalance of distribution feeders, thus reducing extra power loss and increasing the operating efficiency of three-phase induction motors.

COMPARISON OF BRAZILIAN STANDARDS FOR THE QUALIFICATION OF THREE-PHASE INDUCTION MOTORS AGAINST A GLOBAL SCENARIO

Electric motors are considered the most important equipment among those that consume final electric energy in Brazil. It is estimated that the induction motors and the systems driven by them are responsible for approximately 70% of the energy consumption of the Brazilian industrial sector. Countries like Japan, members of the European Union, the United States, Australia, India, and Brazil have specific standards to qualify their equipment.  These, among other countries, have regulatory or even mandatory regime mechanisms that classify the efficiency of three-phase induction motors, using specific standards and regulations. In this way, this article aims to compare the application of national standard methods with international methods, making it possible to qualify the national standard against a global scenario. This articles compares the test standards IEEE 112 Method B, IEC 60034-2-1, JEC 37 and ABNT NBR 17094-3, these standards have different methodologies, so that when the same engine is tested by them their efficiency can present different results, generating large discourses among international committees on which standard is the most appropriate for this type of trial.

Evaluation of uncertainty for the efficiency of three-phase induction motor using FEA

Evaluation of uncertainty for the efficiency of three-phase induction motor using FEA

Simple and Accurate Algorithm for Small- and Medium-Sized Three-Phase IM Efficiency Estimation Based on No-Load Tests

This paper presents a simple and accurate industrial tool that can be used to estimate the full-load efficiency of three-phase induction motors based on no-load tests. The objective of this research work is to eliminate the need for the expensive dynamometer test, which is available only in well-equipped laboratories and provide electric motor service centers in North America with a user-friendly tool that enables the centers to have their rewound, refurbished, or any existing motors evaluated for efficiency prior to delivery to customers. The proposed technique utilizes a test data of 129 motors, ranging from 1 to 500 hp, tested in Hydro-Quebec Laboratory as per IEEE Std. 112B and CAN/CSA C390 standards procedures. The technique also utilizes a recently proposed stray-load loss formula. The algorithm is validated by recalculating the efficiency of the 195 motors by using the proposed technique. The results show an acceptable degree of accuracy. Error analysis study is conducted to examine the level of uncertainty within the accuracy of the proposed algorithm. The outcome of the study completely supports the algorithm. A spreadsheet-based software is designed to turn the algorithm into a practical user-friendly industrial tool.

Повышение эффективности использования трехфазных асинхронных электродвигателей при питании от однофазной сети

Повышение эффективности использования трехфазных асинхронных электродвигателей при питании от однофазной сети

Uncertainty Issues in Direct and Indirect Efficiency Determination for Three-Phase Induction Motors: Remarks About the IEC 60034-2-1 Standard

Electric motors and the systems they drive are the single largest electrical end-use; it is estimated that they consume between 43% and 46% of all global electricity consumption. Recent studies show that efficiency values of induction motors can be successfully increased, with improvements up to 20%–30%. In 2009, the European Commission published a new regulation (640/2009) concerning requirements for the eco-compatible design of electric motors. In such a scenario, the experimental determination of induction motor efficiency is getting more and more important, because of the need of placing these motors in the right energy efficiency levels defined by international regulations. The correct motor classification strictly depends on the uncertainty associated with the efficiency determination. According to the IEC 60034-2-1 standard, the efficiency of three-phase induction motors can be determined by applying the direct or indirect efficiency technique. The direct procedure is suggested for low uncertainty efficiency measurements of single-phase induction motors and three-phase motors with rated power ≤1 kW. In this paper, we propose a comparative analysis between direct and indirect efficiency determination for three-phase induction motors, according to the IEC 60034-2-1 standard. The contribution of this paper consists in the comparison between the uncertainty calculations in indirect and direct efficiency determination for induction motors, to investigate the advisability of adopting the direct efficiency determination as reference method, because it is easier to implement and it has a good accuracy. This task is carried out starting from the accuracy requirements for measurement equipment, as demanded by the Guide to the Expression of Uncertainty in Measurement GUM. Some experimental results obtained with the indirect and direct efficiency determinations on a 3-kW three-phase two-pole induction motor are presented and discussed. A final suggestion related to a future version of IEC 60034-2-1 is also reported.

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.

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>

The Next Generation Motor

There has been a push toward higher efficiencies in the petrochemical industry. This can be seen in the revisions of IEEE 841, which is expected to promote NEMA Premium as the standard, sometime in the near future. Leading motor manufacturers have been motivated by these industry-driven efficiency improvements to investigate the optimization of manufacturing processes and designs to further improve the efficiency of three-phase induction motors. It is very important to make the industrial users fully understand how losses are generated and identify the factors that reduce these significantly, at an acceptable cost for the investment of the motor. Life-cycle costs should also be investigated. This article focuses on the new technologies, designs, and processes being introduced to improve the efficiency of three-phase induction motors.

Electrical steels for high-efficiency motors

The aim of this paper is to evaluate the influence of electrical steels on the efficiency of three-phase induction motors. A computer procedure has been developed to predict motor performance with different electrical steels and to optimise motor design in order to reduce operating costs. Significant variations in rated efficiency have been found and the choice of electrical steels has turned out to be an important factor in motor design. The paper presents the proposed analysis and the principal results obtained in the case of two motor sizes (1.5 and 7.5 kW) and six different electrical steels.

Calculating the efficiency of three-phase induction motors

A method for computing the efficiency of a three-phase induction motor using the input phassor currents for blocked motor, no load, and running with load, is presented.