Operation Of Three-phase Induction Motors Research Articles

Automatic Switching of Three Phase Induction Motor during Fault Condition

Abstract: Three-Phase Induction Motor Automated Transition in Defective Conditions Maintaining the effective operation of three-phase induction motors is crucial in a variety of industrial contexts. However, malfunctions such as phase inconsistency, voltage drop, and overcurrent can seriously impair motor performance, leading to loss of operation and possible damage. This article introduces an automatic switching method designed to improve the fault-tolerance capacity of induction motors in order to address these issues. The system uses advanced fault detection algorithms to identify abnormal conditions quickly and enable a seamless transition to backup power or other configurations. It also incorporates preventive measures to guard against phase abnormalities and voltage variations that could harm the motor. Through simulation and real-world testing, the suggested system's dependability and effectiveness are confirmed, highlighting its potential to guarantee continuous motor running in industrial applications, a three-phase induction motor must be automatically switched on. A two-motor system a primary motor and a backup motor is shown in this study. If the primary motor fails, the backup motor is automatically turned on. Microcontroller design controls the entire switching process.

Early and Intelligent Bearing Fault Detection Using Adaptive Superlets

Faults in bearings interrupt the operation of three-phase induction motors (IMs) and disturb factory production. Vibration signal analysis, feature extraction, and incorporation of artificial intelligence can enhance the ability of fault detection in bearings. However, implementing these techniques is challenging in industries due to harsh environmental conditions and massive computational power. Prioritizing the issue, this article presents a fusion method considering the time-frequency contents of vibration signals via the super-resolution property of wavelets and a two-dimensional convolutional neural network (2-D-CNN). First, a laboratory-based real-time process is considered with Variable Frequency Drive (VFD) driven IM which is also exposed to environmental vibration. In the present work, a piezoelectric sensor is used to collect the vibration of IM during operation. Then the collected time-series signals are stored in a computer through a Data Acquisition System (DAS). Further, signals are segmented in small windows to extract respective feature images using Continuous Wavelet Transform (CWT), Stockwell Transform (ST), and Adaptive Superlet Transform (ASLT). Thereafter, the image resolution is optimally resized and fed to a 2-D-CNN model for multi-label classification of the bearings. It is observed that ASLT-2-D-CNN with 32×32×3 resolution outperforms the other two fusion methods as it reports high accuracy and reduces runtime (training and testing) along with memory usage. The robustness of ASLT-2-D-CNN is also validated with two open-source bearing datasets. Thus, the result indicates that the proposed method for bearing fault detection can be deployed in the field to make IMs safe which reduces the maintenance cost of the industry.

Experimental Validation of a Three-Phase Induction Motor Operating with a Three-Phase Bidirectional Variable Speed Drive

The three-phase induction motor is the main electric motor used in industrial applications, contributing significantly to the industrial electricity consumption. Additionally, the traditional variable speed drivers, due to the internal constitution based on a passive rectifier, co

Thermal Analysis of Low-Power Three-Phase Induction Motors Operating under Voltage Unbalance and Inter-Turn Short Circuit Faults

Three-phase induction motors are considered to be the workhorse of industry. Therefore, induction motor faults are not only the cause of users’ frustrations but they also drive up the costs related to unexpected breakdowns, repair actions, and safety issues. One of the most critical faults in three-phase induction motors is related to the occurrence of inter-turn short circuits, due to its devastating consequences. The topic of inter-turn short-circuit faults in three-phase induction motors has been discussed over recent decades by several researchers. These studies have mainly dealt with early fault detection to avoid dramatic consequences. However, they fall short of addressing the potential burnout of the induction motor before the detection step. Furthermore, the cumulative action played by an inevitable degree of unbalanced supply voltages may exacerbate such consequences. For that reason, in deep detail, this paper delves into the thermal analysis of the induction motor when operating under these two harsh conditions: unbalanced supply voltages and the presence of the most incipient type of inter-turn short-circuit condition—a short-circuit between two turns only. In this work, the finite element method has been applied to create the faulty scenarios, and a commercial software (Flux2D) has been used in order to simulate the electromagnetic and thermal behavior of the machine for various degrees of severity of the aforementioned faulty modes. The obtained results confirm that the diagnostic tools reported in the literature might not be effective, failing to warrant the required lead time so that suitable actions can be taken to prevent permanent damage to the machine.

A New Definition of Voltage Unbalance Using Supply Phase Shift

Studies on voltage unbalance have revealed its detrimental effects on the operation of three-phase induction motors (TPIM) due to the production of negative-sequence current and torque. Voltage unbalance has been defined in different ways over the years, and each of these definitions is limited in scope in one form or the order, e.g. the neglect or inadequate consideration of the phase angle of the supply in these definitions. The complex voltage unbalance factor captures the phase angle using the ratio of the sequence components, but there is a challenge on the interpretation of the random angle θv with respect to the supply. In this study, a novel definition of phase unbalance is proposed which considers the normal 120° displacement of the three phases of the supply. A comparative analysis of all the definitions is presented using four operational supply case studies for a TPIM, and the results may ultimately impact control strategies.

The impact of supply phase shift on the three phase induction motor operation

The performance of a three-phase induction motor operating under supply unbalance conditions has been the focus of many research works using various methods. Most of the studies have focused majorly on voltage magnitude unbalance without due analysis to determine the effect of deviations in the supply phase angle from the 120° phase to phase displacement. This research investigates the significance of supply phase shift on the performance of a three-phase induction motor by applying a novel phase shift unbalance definition to the zero, negative and positive sequence components model of the motor. The test results reveal that when both phase angle shift and voltage magnitude unbalance occur simultaneously during motor operation the effect of the phase shift dominates over the effects of the voltage magnitude unbalance. This study shows that phase angle unbalance has a severe consequence on three phase motor performance.

A method for real-time wireless monitoring of the efficiency and conditions of three-phase induction motor operation

Concerning the primary aim of attending to the requirements used in the monitoring of induction motor efficiency, along with prioritizing a low intrusion level, the Literature presents various methods that need only the voltages, currents and some rotor speed cases. In a general sense, these methods estimate the torque on the machine shaft, along with calculate the output power and efficiency, through the use of a variety of different techniques. In this context, the present study proposes a real time wireless monitoring method over the operation conditions and efficiency of the three-phase induction motors. The method proposed herein estimates through the values measured on the three-phase voltages and currents and the equivalent circuit of the machine, the torque and speed of the shaft. Based on these estimates, both output power and efficiency can be calculated. The equivalent circuit of the machine is estimated through an iterative algorithm that uses only the data from the machine plate and the resistance of the stator, as will be shown in this study.

A Novel In Situ Efficiency Estimation Algorithm for Three-Phase Induction Motors Operating With Distorted Unbalanced Voltages

This paper presents a novel algorithm for in situ efficiency estimation for induction motors operating with unbalanced distorted voltages. The proposed technique utilizes the genetic algorithm, IEEE form F2-method F1 calculations, large motor test database, and a novel stray-load loss formula. The technique is evaluated by testing three small- and medium-sized induction motors with different combinations of voltage unbalance and total harmonic distortion. The results showed acceptable accuracy. The repeatability and usability of the technique with balanced sinusoidal voltages are also validated. The technique may be used as a potential industrial tool that can help derate induction motors in the presence of voltage unbalance and harmonics.

Procedure for Determining Induction Motor Efficiency Working Under Distorted Grid Voltages

In electric power systems, it is very common to find problems of power quality. The flow of harmonics significantly affect the operation of three-phase induction motors, and its energy characterization becomes difficult. There are different methods in situ to estimate motor efficiency. However, it is necessary to deepen the in situ efficiency analysis under nonsinusoidal voltage conditions. In this paper, a procedure is presented based on the equivalent circuits with losses segregation and using a bacterial foraging algorithm (BFA). It allows induction motors' energy efficiency determination in field conditions with low invasiveness and working under harmonic distortion. The method was successfully tested on a 1.5 kW motor fed with significant levels of voltage harmonic.

Analysis of Two-Phase Operation Mechanism of Three-Phase Motor Based on Capacitor Phase Shift Method

In the absence of a three-phase power source, single-phase operation of three-phase induction motor used single-phase power source had a certain practical significance. In this paper, utilized symmetrical component method analysed the asymmetric circuit system of motor, will be voltage and current of the three-phase stator windings decomposed into positive, negative and zero sequence three groups symmetrical components. The theory is analyzed and the formula is deduced of capacitor phase shift method, solved the problem of starting torque, proposed to add starting capacitors and deduced the optimal value of starting capacitor. Finally, the single-phase operation of three-phase induction motor is simulated and verified by simulation software.

Control of Zero Sequence Braking for a Three-phase Induction Motor Operating from Single-phase Supply with a Controlled Capacitor

Control of Zero Sequence Braking for a Three-phase Induction Motor Operating from Single-phase Supply with a Controlled Capacitor

An Active–Reactive Power Method for the Diagnosis of Rotor Faults in Three-Phase Induction Motors Operating Under Time-Varying Load Conditions

This paper presents a new method to diagnose rotor faults in operating three-phase induction motors under the presence of time-varying loads. The proposed diagnostic strategy relies on a combined analysis of the amplitude and phase spectra of the instantaneous active and reactive powers of the motor, and allows to discriminate the effects introduced by a rotor fault from the ones caused by an oscillating load torque, even when these phenomena occur simultaneously. A theoretical analysis carried out using a linearized model of the induction motor in a synchronous reference frame, complemented with several simulation and experimental results, confirms the validity of the proposed diagnostic approach.

Electronically Switched Capacitor-fed Three-phase Induction Motor Operating from Single-phase Supply

The transient behavior of a three-phase induction motor operating with a single-phase supply using a switching capacitor as a phase converter is considered in this article. An electronically controlled capacitor, which employs one fixed capacitor with an electronic switch, is used to improve the performance of the three-phase induction motor operating from a single-phase supply. Variable capacitor values are obtained by controlling the duty cycle of the electronic switch. Instantaneous symmetrical components are used in modeling the motor, including the switching capacitor. Theoretical studies have been carried out for the system considered, and the results are presented and discussed. The results presented include transient speed, current, and torque patterns under starting and running conditions. The validation of the developed mathematical model by computer simulation and experimental results in comparison with conventional operation using one or two fixed capacitor values prove the accuracy and the strength in the proposed method.

A MATLAB-based graphical technique for amortization study of adjustable speed drives

Economic justification of electric drives is the primary reason for many applications. However, the cumbersome trial-and-error calculations necessary to present this aspect often leads to omission of the topic in electric drives courses. This paper presents a MATLAB-based program that generates plots of input power and shaft torque for variable-frequency operation of three-phase induction motors. Based on these graphs, an example is presented illustrating how a cost amortization study for an adjustable speed drive application can be presented with minimal effort and lecture time.

Balanced operation of three-phase induction motor with asymmetrical stator windings connected to single-phase supply system

Analytical evaluation for the performance characteristics of an induction motor having three different stator windings connected in star and in delta configurations when fed from a single-phase supply system is present. Equations for predicting the performance of an asymmetrical three-phase induction motor are developed. Conditions for balanced operation are discussed, based on these equations, for both star and delta-connected motors, showing that there exist many combinations of turns-ratios and capacitor values for satisfying the balancing conditions. The performance characteristics of the motor are investigated under various balancing conditions.

Operation of three-phase induction motors connected to one-phase supply

The behavior of a three-phase induction motor is analyzed operating according to the Steinmetz connection, conceived to allow operation of small rating motors connected to a one-phase supply and with a small degree of voltage unbalance. The conditions for canceling the negative sequence component of the stator winding terminal voltages and currents are also established. The increase in electromagnetic torque deriving from balancing with capacitors and the overvoltages closely related to the changes in amplitude and phase of positive sequence motor impedance verified during rotor acceleration are emphasized. Results presented by considering a capacitor in parallel to one of those phases connected to the motor terminal switched off from the three-phase supply define the requirements for correct capacitor selection and switching off in order to obtain proper motor behavior in the whole slip range from starting to the final operating point. A careful evaluation of the amplitude and phase of the positive sequence impedance should be taken into account for capacitor application to be considered in reducing the degree of unbalance during motor starting and even in normal operating slip range. This will be very useful for reliable capacitor specification and for properly defining rotor speeds at the instant of capacitor switching off.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The operation of three-phase induction motors with unsymmetrical impedance in the secondary circuit

The operation of an induction motor at one-half normal speed against appreciable load, by means of unbalanced impedance in the secondary circuit, is shown to be a practicable possibility with accurately predictable characteristics. Precautions must be taken to prevent saturation of the main magnetic circuit of the machine, and in some cases it may be essential to limit the injection of low-frequency currents into the supply system. Simple solutions to these problems are described, and it is concluded that the method has sufficient merits to justify its use in certain applications where a speed reduction to about one-half the normal value is required.